The Amanda Knox Test: How an Hour on the Internet Beats a Year in the Courtroom

post by komponisto · 2009-12-13T04:16:20.840Z · LW · GW · Legacy · 649 comments

Contents

    Note: The quantitative elements of this post have now been revised significantly.
  The Lawfulness of Murder: Inference Proceeds Backward, from Crime to Suspect
  Epistemic Ruthlessness: Following the Strong Signal
  Conclusion: The Amanda Knox Test
None
649 comments

Note: The quantitative elements of this post have now been revised significantly.

Followup to: You Be the Jury: Survey on a Current Event

All three of them clearly killed her. The jury clearly believed so as well which strengthens my argument. They spent months examining the case, so the idea that a few minutes of internet research makes [other commenters] certain they're wrong seems laughable

- lordweiner27, commenting on my previous post

The short answer: it's very much like how a few minutes of philosophical reflection trump a few millennia of human cultural tradition.

Wielding the Sword of Bayes -- or for that matter the Razor of Occam -- requires courage and a certain kind of ruthlessness. You have to be willing to cut your way through vast quantities of noise and focus in like a laser on the signal.

But the tools of rationality are extremely powerful if you know how to use them.

Rationality is not easy for humans. Our brains were optimized to arrive at correct conclusions about the world only insofar as that was a necessary byproduct of being optimized to pass the genetic material that made them on to the next generation. If you've been reading Less Wrong for any significant length of time, you probably know this by now. In fact, around here this is almost a banality -- a cached thought. "We get it," you may be tempted to say. "So stop signaling your tribal allegiance to this website and move on to some new, nontrivial meta-insight."

But this is one of those things that truly do bear repeating, over and over again, almost at every opportunity. You really can't hear it enough. It has consequences, you see. The most important of which is: if you only do what feels epistemically "natural" all the time, you're going to be, well, wrong. And probably not just "sooner or later", either. Chances are, you're going to be wrong quite a lot.

To borrow a Yudkowskian turn of phrase: if you don't ever -- or indeed often -- find yourself needing to zig when, not only other people, but all kinds of internal "voices" in your mind are loudly shouting for you to zag, then you're either a native rationalist -- a born Bayesian, who should perhaps be deducing general relativity from the fall of an apple any minute now -- or else you're simply not trying hard enough.    

Oh, and another one of those consequences of humans' not being instinctively rational?

Two intelligent young people with previously bright futures, named Amanda and Raffaele, are now seven days into spending the next quarter-century of their lives behind bars for a crime they almost certainly did not commit.

"Almost certainly" really doesn't quite capture it. In my previous post I asked readers to assign probabilities to the following propositions:

1. Amanda Knox is guilty (of killing Meredith Kercher)
2. Raffaele Sollecito is guilty (of killing Meredith Kercher)
3. Rudy Guédé is guilty (of killing Meredith Kercher)

I also asked them to guess at how closely they thought their estimates would match mine.

Well, for comparison, here are mine (revised):

1. Negligible. Small. Hardly different from the prior, which is dominated by the probability that someone in whatever reference class you would have put Amanda into on January 1, 2007 would commit murder within twelve months. Something on the order of 0.001 0.01 or 0.1 at most.  
2. Ditto.
3. About as high as the other two numbers are low. 0.999 0.99 as a (probably weak) lower bound.

Yes, you read that correctly. In my opinion, there is for all intents and purposes zero Bayesian evidence that Amanda and Raffaele are guilty. Needless to say, this differs markedly from the consensus of the jury in Perugia, Italy. 

How could this be?

Am I really suggesting that the estimates of eight jurors -- among whom two professional judges -- who heard the case for a year, along with something like 60% of the Italian public and probably half the Internet (and a significantly larger fraction of the non-American Internet), could be off by a minimum of three orders of magnitude (probably significantly more) such a large amount? That most other people (including most commenters on my last post) are off by no fewer than two?

Well, dear reader, before getting too incredulous, consider this. How about averaging the probabilities all those folks would assign to the proposition that Jesus of Nazareth rose from the dead, and calling that number x. Meanwhile, let y be the correct rational probability that Jesus rose from the dead, given the information available to us.

How big do you suppose the ratio x/y is?

Anyone want to take a stab at guessing the logarithm of that number?

Compared to the probability that Jesus rose from the dead, my estimate of Amanda Knox's culpability makes it look like I think she's as guilty as sin itself.

And that, of course, is just the central one of many sub-claims of the hugely complex yet widely believed proposition that Christianity is true. There are any number of other equally unlikely assertions that Amanda would have heard at mass on the day after being found guilty of killing her new friend Meredith (source in Italian) -- assertions that are assigned non-negligible probability by no fewer than a couple billion of the Earth's human inhabitants.

I say this by way of preamble: be very wary of trusting in the rationality of your fellow humans, when you have serious reasons to doubt their conclusions.

The Lawfulness of Murder: Inference Proceeds Backward, from Crime to Suspect

We live in a lawful universe. Every event that happens in this world -- including human actions and thoughts -- is ultimately governed by the laws of physics, which are exceptionless. 

Murder may be highly illegal, but from the standpoint of physics, it's as lawful as everything else. Every physical interaction, including a homicide, leaves traces -- changes in the environment that constitute information about what took place.

Such information, however, is -- crucially -- local. The further away in space and time you move from the event, the less entanglement there is between your environment and that of the event, and thus the more difficult it is to make legitimate inferences about the event. The signal-to-noise ratio decreases dramatically as you move away in causal distance from the event. After all, the hypothesis space of possible causal chains of length n leading to the event increases exponentially in n.

By far the most important evidence in a murder investigation will therefore be the evidence that is the closest to the crime itself -- evidence on and around the victim, as well as details stored in the brains of people who were present during the act. Less important will be evidence obtained from persons and objects a short distance away from the crime scene; and the importance decays rapidly from there as you move further out.

It follows that you cannot possibly expect to reliably arrive at the correct answer by starting a few steps removed in the causal chain, say with a person you find "suspicious" for some reason, and working forward to come up with a plausible scenario for how the crime was committed. That would be privileging the hypothesis. Instead, you have to start from the actual crime scene, or as close to it as you can get, and work backward, letting yourself be blown by the winds of evidence toward one or more possible suspects.

In the Meredith Kercher case, the winds of evidence blow with something like hurricane force in the direction of Rudy Guédé. After the murder, Kercher's bedroom was filled with evidence of Guédé's presence; his DNA was found not only on top of but actually inside her body. That's about as close to the crime as it gets. At the same time, no remotely similarly incriminating genetic material was found from anyone else -- in particular, there were no traces of the presence of either Amanda Knox or Raffaele Sollecito in the room (and no, the supposed Sollecito DNA on Meredith's bra clasp just plain does not count -- nor, while we're at it, do the 100 picograms [about one human cell's worth] of DNA from Meredith allegedly on the tip of a knife handled by Knox, found at Sollecito's apartment after the two were already suspects; these two things constituting pretty much the entirety of the physical "evidence" against the couple).

If, up to this point, the police had reasons to be suspicious of Knox, Sollecito, and Guédé, they should have cleared Knox and Sollecito at once upon the discovery that Guédé -- who, by the way, was the only one to have fled the country after the crime -- was the one whom the DNA matched. Unless, that is, Knox and Sollecito were specifically implicated by Guédé; after all, maybe Knox and Sollecito didn't actually kill the victim, but instead maybe they paid Guédé to do so, or were otherwise involved in a conspiracy with him. But the prior probabilities of such scenarios are low, even in general -- to say nothing of the case of Knox and Sollecito specifically, who, tabloid press to the contrary, are known to have had utterly benign dispositions prior to these events, and no reason to want Meredith Kercher dead.

If Amanda Knox and Raffaele Sollecito were to be in investigators' thoughts at all, they had to get there via Guédé -- because otherwise the hypothesis (a priori unlikely) of their having had homicidal intent toward Kercher would be entirely superfluous in explaining the chain of events that led to her death.  The trail of evidence had led to Guédé, and therefore necessarily had to proceed from him; to follow any other path would be to fatally sidetrack the investigation, and virtually to guarantee serious -- very serious -- error. Which is exactly what happened.

There was in fact no inferential path from Guédé to Knox or Sollecito. He never implicated either of the two until long after the event; around the time of his apprehension, he specifically denied that Knox had been in the room. Meanwhile, it remains entirely unclear that he and Sollecito had ever even met.

The hypotheses of Knox's and Sollecito's guilt are thus seen to be completely unnecessary, doing no explanatory work with respect to Kercher's death. They are nothing but extremely burdensome details.  

Epistemic Ruthlessness: Following the Strong Signal

All of the "evidence" you've heard against Knox and Sollecito -- the changing stories, suspicious behavior, short phone calls, washing machine rumors, etc. -- is, quite literally, just noise.

But it sounds so suspicious, you say. Who places a three-second phone call? 

As humans, we are programmed to think that the most important kinds of facts about the world are mental and social -- facts about what humans are thinking and planning, particularly as regards to other humans. This explains why some people are capable of wondering whether the presence of (only) Rudy Guédé's DNA in and on Meredith's body should be balanced against the possibilty that Meredith may have been annoyed at Amanda for bringing home boyfriends and occasionally forgetting to flush the toilet -- that might have led to resentment on Amanda's part, you see.

That's an extreme example, of course -- certainly no one here fell into that kind of trap. But at least one of the most thoughtful commenters was severely bothered by the length of Amanda's phone calls to Meredith. As -- I'll confess -- was I, for a minute or two.

I don't know why Amanda wouldn't have waited longer for Meredith to pick up. (For what it's worth, I myself have sometimes, in a state of nervousness, dialed someone's number, quickly changed my mind, then dialed again a short time later.) But -- as counterintuitive as it may seem -- it doesn't matter. The error here is even asking a question about Amanda's motivations when you haven't established an evidentiary (and that means physical) trail leading from Meredith's body to Amanda's brain. (Or even more to the point, when you have established a trail that led decisively elsewhere.)

Maybe it's "unlikely" that Amanda would have behaved this way if she were innocent. But is the degree of improbabilty here anything like the improbability of her having participated in a sex-orgy-killing without leaving a single piece of physical evidence behind? While someone else left all kinds of traces? When you had no reason to suspect her at all without looking a good distance outside Meredith's room, far away from the important evidence?

It's not even remotely comparable. 

Think about what you're doing here: you are invoking the hypothesis that Amanda Knox is guilty of murder in order to explain the fact that she hung up the phone after three seconds. (Remember, the evidence against Guédé is such that the hypothesis of her guilt is superfluous -- not needed -- in explaining the death of Meredith Kercher!)

Maybe that's not quite as bad as invoking a superintelligent deity in order to explain life on Earth; but it's the same kind of mistake: explaining a strange thing by postulating a far, far stranger thing.

"But come on," says a voice in your head. "Does this really sound like the behavior of an innocent person?"

You have to shut that voice out. Ruthlessly. Because it has no way of knowing. That voice is designed to assess the motivations of members of an ancestral hunter-gather band. At best, it may have the ability to distinguish the correct murderer from between 2 and 100 possibilities -- 6 or 7 bits of inferential power on the absolute best of days. That may have worked in hunter-gatherer times, before more-closely-causally-linked physical evidence could hope to be evaluated. (Or maybe not -- but at least it got the genes passed on.)

DNA analysis, in contrast, has in principle the ability to uniquely identify a single individual from among the entire human species (depending on how much of the genome is looked at; also ignoring identical twins, etc.) -- that's more like 30-odd bits of inferential power. In terms of epistemic technology, we're talking about something like the difference in locomotive efficacy between a horsedrawn carriage and the Starship Enterprise. Our ancestral environment just plain did not equip our knowledge-gathering intuitions with the ability to handle weapons this powerful.

We're talking about the kind of power that allows us to reduce what was formerly a question of human social psychology -- who made the decision to kill Meredith? -- to one of physics. (Or chemistry, at any rate.)

But our minds don't naturally think in terms of physics and chemistry. From an intuitive point of view, the equations of those subjects are foreign; whereas "X did Y because he/she wanted Z" is familiar. This is why it's so difficult for people to intuitively appreciate that all of the chatter about Amanda's "suspicious behavior" with various convincing-sounding narratives put forth by the prosecution is totally and utterly drowned out to oblivion by the sheer strength of the DNA signal pointing to Guédé alone.

This rationalist skill of following the strong signal -- mercilessly blocking out noise -- might be considered an epistemic analog of the instrumental "shut up and multiply": when much is at stake, you have to be willing to jettison your intuitive feelings in favor of cold, hard, abstract calculation.

In this case, that means, among other things, thinking in terms of how much explanatory work is done by the various hypotheses, rather than how suspicious Amanda and Raffaele seem

Conclusion: The Amanda Knox Test

I chose the title of this post because the parallel structure made it sound nice. But actually, I think an hour is a pretty weak upper bound on the amount of time a skilled rationalist should need to arrive at the correct judgment in this case.

The fact is that what this comes down to is an utterly straightforward application of Occam's Razor. The complexity penalty on the prosecution's theory of the crime is enormous; the evidence in its favor had better be overwhelming. But instead, what we find is that the evidence from the scene -- the most important sort of evidence by a huge margin -- points with literally superhuman strength toward a mundane, even typical, homicide scenario. To even consider theories not directly suggested by this evidence is to engage in hypothesis privileging to the extreme.

So let me say it now, in case there was any doubt: the prosecution of Amanda Knox and Raffaele Sollecito, culminating in last week's jury verdict -- which apparently was unanimous, though it didn't need to be under Italian rules -- represents nothing but one more gigantic, disastrous rationality failure on the part of our species.

How did Less Wrong do by comparison? The average estimated probability of Amanda Knox's guilt was 0.35 (thanks to Yvain for doing the calculation). It's pretty reasonable to assume the figure for Raffaele Sollecito would be similar. While not particularly flattering to the defendants (how would you like to be told that there's a 35% chance you're a murderer?), that number makes it obvious we would have voted to acquit. (If a 65% chance that they didn't do it doesn't constitute  "reasonable doubt" that they did...)

The commenters whose estimates were closest to mine -- and, therefore, to the correct answer, in my view -- were Daniel Burfoot and jenmarie. Congratulations to them. (But even they were off by a factor of at least ten!)

In general, most folks went in the right direction, but, as Eliezer noted, were far too underconfident -- evidently the result of an exorbitant level of trust in juries, at least in part. But people here were also widely making the same object-level mistake as (presumably) the jury: vastly overestimating the importance of "psychological" evidence, such as Knox's inconsistencies at the police station, as compared to "physical" evidence (only Guédé's DNA in the room).

One thing that was interesting and rather encouraging, however, is the amount of updating people did after reading others' comments -- most of it in the right direction (toward innocence).

[EDIT: After reading comments on this post, I have done some updating of my own. I now think I failed to adequately consider the possibility of my own overconfidence. This was pretty stupid of me, since it meant that the focus was taken away from the actual arguments in this post, and basically toward the issue of whether 0.001 can possibly be a rational estimate for anything you read about on the Internet. The qualitative reasoning of this post, of course, stands. Also, the focus of my accusations of irrationality was not primarily the LW community as reflected in my previous post; I actually think we did a pretty good job of coming to the right conclusion given the information provided -- and as others have noted, the levelheadedness with which we did so was impressive.]

For most frequenters of this forum, where many of us regularly speak in terms of trying to save the human species from various global catastrophic risks, a case like this may not seem to have very many grand implications, beyond serving as yet another example of how basic principles of rationality such as Occam's Razor are incredibly difficult for people to grasp on an intuitive level. But it does catch the attention of someone like me, who takes an interest in less-commonly-thought-about forms of human suffering.

The next time I find myself discussing the "hard problem of consciousness", thinking in vivid detail about the spectrum of human experience and wondering what it's like to be a bat, I am going to remember -- whether I say so or not -- that there is most definitely something it's like to be Amanda Knox in the moments following the announcement of that verdict: when you've just learned that, instead of heading back home to celebrate Christmas with your family as you had hoped, you will be spending the next decade or two -- your twenties and thirties -- in a prison cell in a foreign country. When your deceased friend's relatives are watching with satisfaction as you are led, sobbing and wailing with desperation, to a van which will transport you back to that cell. (Ever thought about what that ride must be like?) 

While we're busy eliminating hunger, disease, and death itself, I hope we can also find the time, somewhere along the way, to get rid of that, too.

(The Associated Press reported that, apparently, Amanda had some trouble going to sleep after the midnight verdict.) 

I'll conclude with this: the noted mathematician Serge Lang was in the habit of giving his students "Huntington tests" -- named in reference to his controversy with political scientist Samuel Huntington, whose entrance into the U.S. National Academy of Sciences Lang waged a successful campaign to block on the grounds of Huntington's insufficient scientific rigor.

The purpose of the Huntington test, in Lang's words, was to see if the students could "tell a fact from a hole in the ground".

I'm thinking of adopting a similar practice, and calling my version the Amanda Knox Test. 

Postscript: If you agree with me, and are also the sort of person who enjoys purchasing warm fuzzies separately from your utilons, you might consider donating to Amanda's defense fund, to help out her financially devastated family. Of course, if you browse the site, you may feel your (prior) estimate of her guilt taking some hits; personally, that's okay with me.

649 comments

Comments sorted by top scores.

comment by dilaudid · 2009-12-13T17:23:15.610Z · LW(p) · GW(p)

Komponisto makes a strange assertion. The prior is not the reference that "someone would commit murder" - there is a body. A more appropriate prior is "someone who lives with someone who was murdered committed that murder" - I'm guessing that base probability is of the order of 0.1. Once we take into account that AK and MK aren't in a relationship, AK is female, and there is very strong evidence that someone else committed the murder then I'd agree that the probability drops, but these pieces of evidence don't cancel out leaving us with the original prior - the final probability may be higher or lower.

Also the "complexity penalty on the prosecution's theory of the crime is enormous" - that may mean the case was flawed, but it's not evidence she didn't kill MK unless you are willing to give some weight to the conviction (at <0.001, I assume you are not). Or to put it another way, even if the prosecution is completely wrong you cannot set the probability of guilt to 0. This is like assuming AK is guilty because her parents criticized the Italian legal system.

Overall I hope I am a bit more cautious about my abilities than you. In the first half you explain why you, as a human being, cannot be trusted to be rational. Then you set out your case. Why should I trust your rationality, but not others'?

Replies from: brazil84
comment by brazil84 · 2009-12-14T03:48:16.995Z · LW(p) · GW(p)

I think this is a good point, but I would go one step further. Because there was more than one crime committed. In addition to a murder, somebody tried to stage a burglary. Common sense says that whoever staged the burglary was also involved in the murder but it's still 2 separate crimes.

It seems to me that the prior probability that the person who staged the burglary is someone closely associated with Kercher, such as a roommate, is actually pretty high. A close associate would have a strong incentive to try to make the police think that a stranger committed the crime. Whereas a stranger or remote acquaintance would have little or no incentive to do so.

comment by Dreaded_Anomaly · 2011-10-03T20:13:22.242Z · LW(p) · GW(p)

Amanda Knox acquitted.

Justice is finally served.

Replies from: APMason, private_messaging, MarkusRamikin, gwern
comment by APMason · 2011-10-03T20:20:05.551Z · LW(p) · GW(p)

Or at least injustice has stopped being served.

comment by private_messaging · 2014-01-31T09:58:40.734Z · LW(p) · GW(p)

Overturned, though.

With regards to "bayesian" analysis in question, as dilaudid said, the fact that a body was found makes for a fairly high probability that one out of a fairly small number of people connected to the victim has committed or participated in the murder. Even more so for a staged break-in.

The reason why we shouldn't imprison people based on things such as apparently weird behaviour has little to do with it's impact on probability, and everything to do with the potential for the abuses that a subjective criterion would create, as well as discrimination against "weird people" such as borderline autistic. We have to think what is going to happen on the bigger scale if we start using "weirdness" as evidence in the court.

The issue in this case is that the narrative presented by the police seems incredibly improbable even given all the facts, and there are far more probable narratives where she committed a lesser crime (such as being an accessory after the act). People who would commit murder are much rarer than people who may act as an accessory.

comment by MarkusRamikin · 2011-10-05T07:15:20.780Z · LW(p) · GW(p)

That took a while.

BTW, it just struck me, why do we tend to talk about Amanda Knox and fail to mention Rafaelle Sollecito?

Replies from: Desrtopa, wedrifid
comment by Desrtopa · 2011-10-05T22:57:42.142Z · LW(p) · GW(p)

Amanda Knox is American, so she gets more attention from American news media.

Replies from: JoshuaZ, GilgameshDeux
comment by JoshuaZ · 2011-10-05T23:37:23.068Z · LW(p) · GW(p)

And a white female. Don't forget that part.

Replies from: MarkusRamikin
comment by MarkusRamikin · 2011-10-06T05:56:40.507Z · LW(p) · GW(p)

And easier to type out.

comment by GilgameshDeux · 2011-12-15T11:23:11.954Z · LW(p) · GW(p)

As well as a wholesome looking WHITE college student, which makes so many other people with latent homicidal tendencies from the same background feel viciously protective of her innocence!

Replies from: wedrifid
comment by wedrifid · 2011-12-15T12:06:09.923Z · LW(p) · GW(p)

As well as a wholesome looking WHITE college student, which makes so many other people with latent homicidal tendencies from the same background feel viciously protective of her innocence!

Why do we need latent homicidal tendencies to feel protective? That's bizarre.

comment by wedrifid · 2011-10-05T08:15:16.173Z · LW(p) · GW(p)

Mostly because she is more attractive.

Replies from: MarkusRamikin
comment by gwern · 2011-10-03T21:48:23.719Z · LW(p) · GW(p)

Thanks for the link; I've updated both predictions on PB.com.

comment by wedrifid · 2009-12-13T05:34:27.268Z · LW(p) · GW(p)

"But come on," says a voice in your head. "Does this really sound like the behavior of an innocent person?"

Absolutely. I saw the amount of emphasis prosecutors (and 'guilty' advocates) were placing on this sort of crap and immediately updated in favour of innocent. Presenting lots of ridiculous nonsense is evidence that you haven't not anything better.

Replies from: Douglas_Knight
comment by Douglas_Knight · 2009-12-13T16:22:53.492Z · LW(p) · GW(p)

"But come on," says a voice in your head. "Does this really sound like the behavior of an innocent person?"

Absolutely. I saw the amount of emphasis prosecutors (and 'guilty' advocates) were placing on this sort of crap and immediately updated in favour of innocent. Presenting lots of ridiculous nonsense is evidence that you haven't not anything better.

What I found most interesting about this exercise is the number of people who made this deduction. It is an error. They are appealing to the public and the jury, whose rationality you impugn. The prosecutors and especially advocacy websites will present (a lot of) this crap regardless of whether they have better evidence. This is normal behavior for prosecutors, just as changing stories, implicating random people, and signing confessions is normal behavior for innocent people. Similarly, differences in tone and organization of the two advocacy sites is pretty much useless.

Replies from: AnnaGilmour, wedrifid
comment by AnnaGilmour · 2009-12-15T23:42:01.781Z · LW(p) · GW(p)

Douglas, you mention that crap evidence is "normal" even if they have better evidence, but is it normal to not also present the claimed better evidence?

comment by wedrifid · 2009-12-13T21:32:42.474Z · LW(p) · GW(p)

What I found most interesting about this exercise is the number of people who made this deduction. It is an error.

I am not convinced. The ratio of speaking nonsense to providing relevant evidence is a valid signal even with our less than entirely rational species.

comment by bogdanb · 2009-12-13T21:37:34.067Z · LW(p) · GW(p)

I'm a bit curious about something:

If read your post correctly, you feel that you can discount as pretty much irrelevant the opinions of quite a lot of people (jurors, police, etc), on the simple basis that people can be spectacularly wrong on occasion. ( I'm really not sure about this.)

In fact, as far as I can tell, you start from “clean” priors and do all your updating based only on the “physical evidence”; no opinions entering your calculation.

This seems almost OK, but something's nagging at me: how can you obtain thirty bits of confidence in your estimate using only evidence received from other people, via the Internet?

I'm also not sure about this, but your post seems to imply that a “good Bayesian” would be expected to assign that amount of confidence to his answer after only a couple of hours of surfing the Internet. I'm not saying that's impossible, but it really sounds very unlikely to me.

I'd very much like to see a chain of numerical reasoning that reasonably puts a 1:1000 upper-bound on the likelihood that Guédé is innocent, without starting with implicit assumptions of 100% certainty about data read from the net.* If you think an hour on the Internet is enough to reach that kind of certainty, I don't see why writing the calculations (for an upper bound, not the precise value) would take much longer, assuming that one would be gathering data and doing the calculations in one's head during that hour.

(*: EDIT for clarification. By this I mean that, for instance, given claimed evidence E in support of theory T, you don't update on the probability of T given E, but update on the probability of T given “I've read on the Internet that E”. Of course, many claims of E on the Internet have some weight, but I doubt two hours of Internet reading can add lots of weight on non-trivial subjects.)

Replies from: Fuji
comment by Fuji · 2013-10-25T21:32:32.300Z · LW(p) · GW(p)

The discounting of everyone and everything that implies guilt is the only way someone can make an argument that Knox and Sollecito are innocent. The computer shows no activity = experts are wrong. ISP shows no activity = ISP is wrong. Three different witnesses saw them = all wrong. Luminol shows footprints that match Knox and Sollecito = false positive for the Luminol. Expert says Knox shoe print in victim's room = expert wrong. Expert says Sollecito's bloody footprint in bathroom = expert is wrong. DNA = all wrong. This goes on and on.

Given the scenario of accepting that dozens of experts and witnesses are wrong or accepting that the evidence is accurate and they killed Meredith I think the logical choice is obvious.

This site has all the transcripts and is in the process of translating them into English. http://themurderofmeredithkercher.com/

It is easy to see why an hour on the internet beats a year in the courtroom is just foolish. The idea that a bunch of white knights on the internet could match a small army of experts is ludicrous

Replies from: Decius
comment by Decius · 2013-10-26T01:08:04.326Z · LW(p) · GW(p)

I find it much more ludicrous that a small army of experts would have so little disagreement if they weren't privileging a hypothesis. How likely is it that interviews at 0145 and 0545 would be confused and contradictory if the suspect was innocent, as compared to if the suspect was guilty?

Personally, I think that a slightly confused interview history is slight Bayesian evidence of guilt, because someone with a prepared lie is less likely to appear confused about it than someone trying to tell the truth.

Replies from: EHeller
comment by EHeller · 2013-10-26T02:53:12.134Z · LW(p) · GW(p)

I find it much more ludicrous that a small army of experts would have so little disagreement if they weren't privileging a hypothesis.

I'm confused. Why would you expect dramatic expert disagreement in general on matters of fact?

Replies from: Decius, gattsuru
comment by Decius · 2013-10-30T01:47:16.751Z · LW(p) · GW(p)

For one, because they do. The website which contains the claims of evidence has several small internal inconsistencies and notes several cases where the prosecution witnesses do not confirm identical beliefs.

One of the damning things about the DNA evidence is that the experts claim odds of "One in a trillion or two" and "Ten billion to one" that the DNA matches a random person. That requires that the odds of a given person having an identical twin about which they are unaware be less than that, and/or that DNA from a given crime scene be expected to match from about one-half of a living human to a miniscule fraction of all humans, if all humans were tested.

comment by gattsuru · 2013-10-26T04:08:21.253Z · LW(p) · GW(p)

The standards for expert testimony are not very strict, either in the United States or Europe, and there remains significant internal controversy on some important matters within the field of DNA testing.

I've also seen direct conflicts between the claimed testimony on that page and on other reporting sources, although I lack the tools to evaluate which claim is correct at this time.

comment by JimS · 2011-06-20T02:34:20.438Z · LW(p) · GW(p)

Measuring cellphone call times down to "3 seconds" is meaningless. Mobile-to-mobile call setup times over the cellular network can easily be 4-5 seconds or more. While the network is trying to find the phone you called guess what ... you hear ringing on your phone even though a connection hasn't been set up. So it wouldn't be unusual for the caller to hear 5-6 seconds of ringing before the called phone starts ringing. 3 seconds of ringing on the called phone could easily translate into 6-9 seconds of ringing on the calling phone.

In the US, I prefer to hang up before the voice mail prompt. It leaves a missed call message and makes it easier for the called party. But when in Italy, better let the phone ring until voice mail just in case the called party died ....

comment by lordweiner27 · 2009-12-14T11:20:01.837Z · LW(p) · GW(p)

Having review your evidence and some other evidence that I was pointed in the direction of I have to admit I may have been wrong. Knox and the other guy are probably innocent.

There were a few things that lead me to my original conclusion: -The DNA evidence -Amanda changing her story -My belief that it was ridiculous that the police would go to all this effort to frame them if they were innocent.

The DNA evidence has been refuted, I can't say I understand this but I'm willing to accept there is a lot of doubt there.

Amanda changing her story seems like evidence that she is a liar and seems a ridiculous thing to do if you are a murder suspect. (I still think it was really stupid of her and totally the wrong thing to do.) But at the the time she wasn't more of a witness than a suspect and she possibly believed that this would get her off the hook and out of interrogation.

The third point about the police conspiracy is the most interesting. I have a huge bias against conspiracy theories. As soon as anyone starts to go "Wake up sheeple, you're being controlled." I immediately switch off. The quote you use from me at the beginning of your article is partly a reference to this. Of course you are right juries can be wrong. I just tend to think that the simplest answer is normally the best. That's it's more likely that she is guilty, than that the police dept in Italy have a massive desire to convict and innocent woman.

However on reading more about the case, I discovered that the police had a theory it was Knox, Sollecito and Knox's boss before the evidence about Guede turned up. They announced this to the world. When Guede turned up, which normally would have been the end of the case they stuck with their original theory substituting Guede for Knox's boss.
So their motive for wanting to convict Knox and Sollecito was not a conscious devious one but an unconscious subtle one. The didn't want to be embarrassed and shown to be wrong in the eyes of the world media.

Btw, this is the third time I've been proved to be wrong on the internet this week. Either I'm not a very good rationalist or I just spend to much time on the internet.

Replies from: Unknowns
comment by Unknowns · 2009-12-14T11:38:21.451Z · LW(p) · GW(p)

That original theory was based on Knox's testimony-- at that point it wasn't unreasonable for the police to accept it.

Replies from: Jack
comment by Jack · 2009-12-14T13:05:43.091Z · LW(p) · GW(p)

Unless they fed the testimony to her based on a text message that said "See you later." And frankly the conspiracy between the three of them and Knox's active participation in the murder wasn't in the testimony (as far as I can tell) she just reported recalling images of her boss associated with the screams of Kercher. At most it was just a confession to being at the scene.

comment by captcorajus · 2009-12-19T15:19:08.897Z · LW(p) · GW(p)

Here's a thought exercise, that for me clears the confusion in this case. Pretend that you don't already know who the suspects are in this case, and are looking at the evidence to try and find one for the first time. You have no preconceived notion as to who killed Kercher.

Your evidence comes in two weeks after the killing and you have a bloody hand print on a pillow, fingerprints elsewhere in the room, saliva DNA outside the victim and skin or saliva DNA inside the victim as well. All of this is of one person, Rudy Guede.

You look up Rudy Guede and you find that in the weeks prior to the murder he was involved in three separate break-ins involving a knife, but was not arrested. When you try to locate him, you find he has fled the country to Germany.

At this point, do Knox and Sollecito even come into this story as anything other than footnotes? There are no interrogations, no cartwheels, no rumors of bleach purchases, no "foxy knoxy", no stories of sex on a train, none of it. The knife in Sollecito's flat, with a minuscule amount of DNA on the blade that doesn't identify Kercher but can't exclude it never enters the scene. Neither does the bra clasp found 47 days later.

Blood drops of the victim found in a co-habituated bathroom with mixed DNA of roommates doesn't seem all that sinister.

For me, this clears up who the guilty party in this case quite nicely, and takes my "feelings" out of the equation.

Replies from: brazil84
comment by brazil84 · 2009-12-19T17:19:37.750Z · LW(p) · GW(p)

In fairness, aren't you also starting with some or all of the following pieces of evidence?:

(1) A room in the crime scene apartment has been ransacked but no valuables (which were in plain view) were taken;

(2) A window in that same room has been broken with marks suggesting it was broken from the inside;

(3) the same window is on the second floor and can be seen from the street. Further, there is no obvious reason why a burglar would need to get in through an upper floor;

(4) Bloodstains indicate that the victim died with her bra on and the bra was removed a few hours later; and

(5) When the police arrived at the crime scene apartment, one of the victim's flatmates was standing there with her boyfriend and with a mop and a bucket.

Replies from: captcorajus, Feh
comment by captcorajus · 2009-12-19T18:03:54.931Z · LW(p) · GW(p)

1) Actually, Kercher's rent money was missing and Guede's DNA was found in her purse. After her murder he went clubbing and then hopped a train Milan. Where did he get the money to do that? To state there was no robbery doesn't jibe with the evidence. Knox had $2000 in her bank account, and Sollecito's parents are well off. Guede was a known drifter known for his money problems.

2) No, evidence was NOT that window was broke from the inside. The glass was inside the room, and a rock was found. The dispute arises because some glass was below clothing in Filomena's room. However, Filomena was allowed into her room to retrieve personal effects, so the exact placement of clothing is suspect. Furthermore, the building itself is fairly isolated and traffic along the road is minimal.

3) There is a truss next to the window making access relatively easy. An investigator for the defense, dressed in a suite and tie easily scaled it. Rude Guede was an accomplished athlete and basketball player.

4) That's an evaluation of the judge who accepted the prosecutor's contention of the muti person scenario. Scientific testimony at trial contradicts this assertion. In either case, this is evidence open to interpretation. Even if that were true, there is still no evidence that Knox or Sollecito were involved in moving the body! Putting them in the room a SECOND time hours later further creates a logic problem because no evidence of their presence is in the room! What are they, ghosts?? Even if you prove there was more then one assailant, you still have to prove those additional assailants were Knox and Sollecito... which you can't You must UNLEARN what you have learned my friend. ;)

5) No such evidence was presented at trial, and even if it was so, its completely meaningless. How do you get from "a mop and bucket" to "a three way sex crime"? You must have something stronger in addition to the observation for it to have probative value of a crime! If they cleaned the crime scene how did they leave behind Guede's fingerprints and DNA? Either is all there, or its all gone. You can't selectively clean up microscopic evidence... much less with a mop and bucket. Its laughable.

As komponisto stated, it is difficult to be cold in your rational evaluation. You are assigning the mop and bucket a value almost equal to DNA inside the victim when in real comparison they are light years apart in real value.

Replies from: brazil84
comment by brazil84 · 2009-12-19T18:15:47.984Z · LW(p) · GW(p)

Hold on a sec: Are we looking at things from the perspective of the initial evidence available to investigators? Or are we looking at all the evidence in its totality?

These are two separate but related questions:

(1) Does the initial evidence offer a reasonable basis to be suspicious of Knox and/or Sollecito?

(2) Does all the evidence in its totality indicate that Knox and Sollecito are guilty?

It seems to me you just jumped from discussing (1) to discussing (2). If you want to do that, fine, but in that case it's not fair for you to ignore later evidence which developed against Knox and Sollecito.

You are assigning the mop and bucket a value almost equal to DNA

I'm not doing that at all. The mop and bucket are one initial piece of evidence which, when combined with other initial pieces of evidence, form a reasonable basis to be suspicious of Knox and Sollecito.

Replies from: captcorajus
comment by captcorajus · 2009-12-19T18:30:10.585Z · LW(p) · GW(p)

How is the mop and bucket evidence of a crime??? That's an emotional response, not a rational one. You must prove 1) the mop and bucket was used to clean up a crime scene, and 2) that Knox and Sollecito were the one that did it. No proof of 1 exists, so how can you prove 2?

1) I'm saying that if you follow the evidence, Knox and Sollecito never enter the picture as suspects. I do not assign behavior as evidence of a crime without strong physical evidence to cooberate it. All we have initially are the behaviors.

2) The evidence in totality can't connect them to the crime or Guede. Guede is completely connected by the evidence. So how can you prove guilt?

I'm saying this: If you START with the cold hard evidence, and proceed from there, Knox and Sollecito are NOT suspects. Since they are not suspect, their behavior isn't probative, and everything that follows: "Foxy Knoxy", Vibrators in the bathroom, sex on a train, cartwheels at the police station have 0 value as evidence of a crime. Get it?

I'm time warping. Starting with the evidence to find the people, not starting with the people and then trying to find evidence to implicate them. Its a thought exorcise.

Replies from: brazil84
comment by brazil84 · 2009-12-19T18:42:09.254Z · LW(p) · GW(p)

How is the mop and bucket evidence of a crime???"

It's evidence that Knox and Sollecito had been cleaning something up, either because they were trying to conceal evidence of a crime or because they were just doing ordinary cleaning. It would have been a bit of a coincidence for them to have been doing ordinary cleaning on the same day that (1) Knox's roommate was murdered; and (2) Knox suspected that somebody had burglarized her apartment. Not an outrageous coincidence but it does raise the suspiscion level a little.

) I'm saying that if you follow the evidence, Knox and Sollecito never enter the >picture as suspects. I do not assign behavior as evidence of a crime without strong >physical evidence to cooberate it.

So you are saying that INITIALLY, there was no evidence of staging/alteration of the crime scene?

Replies from: captcorajus
comment by captcorajus · 2009-12-19T18:58:10.380Z · LW(p) · GW(p)

I'm saying that Kercher had $200 in cash and it was missing. Guede's DNA was in her purse, and he needed money to flee the country. Thus, there is strong evidence of a robbery. Saying nothing was taken is simply ignoring the facts. Interpretation of staging is exactly that... interpretation. If you say it was staged, that helps support the prosecution's version of the crime, but it does not support the totality of the physical evidence.

You can infer whatever you wish from the mop and bucket, but without substantiating evidence it means nothing.

Replies from: brazil84
comment by brazil84 · 2009-12-19T19:03:17.679Z · LW(p) · GW(p)

Respectfully, does that mean "yes" or "no"?

P.S. By "initially" I mean just looking at the crime scene evidence.

Replies from: captcorajus
comment by captcorajus · 2009-12-19T19:12:41.799Z · LW(p) · GW(p)

Respectfully, it doesn't matter. You're missing the whole point... and I'm not trying to be flip. I apologize if it appears that way. Let's play devil's advocate and say there was unequivocal proof of staging/ alteration of the crime scene occurred. You must now prove that Knox or Sollecito were the ones that did it. Your suspicion that they did it is not evidence.I understand about "initially", but in order to conduct the investigation you must start with the obvious and work from there. I find it very difficult to START my investigation with Knox as a suspect based on what was found initially.

The further away you move from the point of origin of the event, the less accurate your observations will be.

Replies from: brazil84
comment by brazil84 · 2009-12-19T19:23:00.718Z · LW(p) · GW(p)

Let's play devil's advocate and say there was unequivocal proof of staging/ >alteration of the crime scene occurred.

Ok, fine.

You must now prove that Knox or Sollecito were the ones that did it.

I'm a little confused. I thought your point was that the initial physical evidence offered no reason to suspect Knox or Sollecito and therefore subsequent evidence developed against them should be discounted or even disregarded.

In that case, the question is not whether the evidence proves Knox is guilty but whether it provides a reasonable basis to suspect her.

Did I misunderstand you?

Replies from: captcorajus, captcorajus
comment by captcorajus · 2009-12-19T19:49:52.786Z · LW(p) · GW(p)

Here's exactly how Knox arrived on the radar as a suspect. You tell me if this sounds right:

"...Edgardo Giobbi, a police forensic scientist, told the court in Perugia how during a search at the house just hours after the murder, he handed Knox a pair of shoe covers to prevent contaminating the evidence.

"As she put them on she swiveled her hips, pulled a face and said 'hop la' - I thought it was very unusual behavior and my suspicions against her were raised," Mr. Giobbi told the court..."

My reaction to this statement was something along the lines of, "WTF?"

It is natural in ANY investigation to first look at the people who live at the house, but you can't let that give you tunnel vision to the physical evidence around you.

Replies from: erica, brazil84, brazil84
comment by erica · 2009-12-20T10:03:52.390Z · LW(p) · GW(p)

What about the knife wounds?

Were the wounds consistent with different knives or not?

If they were,

and if it is true that the bathmat print was Raff's, and other prints were wiped off the floor, then:

Is it theoretically possible that Raff walked into the room and stabbed a dying woman? - that would not lead to leaving DNA only on the floor and the knife - which may have been a different knife, from the one in the flat, and was discarded and never found?

Surely, if the jury convicted on the basis of the prosecution's story then they must have gone into detail like that in order to examine the plausability of the reasoning?

With all the uncertainty about the many disparate bits of evidence and/or red herrings, I don't see how one can judge the judgement without reading the whole proceedings.

Certainly I agree that there is no real evidence that Raff and Knox were tumbling around the room with Meredith. But I think what is on trial is how murders come about as much as the act itself. That may be a difference in Italian law.

I think some people feel that Knox and Raff may have been morally responsible, by their inconsiderate behaviour. Maybe they were bullying Meredith a bit and playing games that maybe Guede didn't understand.

comment by brazil84 · 2009-12-20T00:10:04.273Z · LW(p) · GW(p)

Here's exactly how Knox arrived on the radar as a suspect.

By the way, as a point of information, do you have a cite for that? TIA.

(Of course my main question is whether I have understood you correctly. Are you saying that the initial physical evidence offered no reason to suspect Knox or Sollecito and therefore subsequent evidence developed against them should be discounted or even disregarded?)

comment by brazil84 · 2009-12-19T19:58:54.493Z · LW(p) · GW(p)

It is natural in ANY investigation to first look at the people who live at the house, but >you can't let that give you tunnel vision to the physical evidence around you.

I agree, but so what? The issue of whether the police developed tunnel vision is a different question.

Anyway, please tell me if I misunderstood you. Your point seems to be that the initial physical evidence offered no reason to suspect Knox or Sollecito and therefore subsequent evidence developed against them should be discounted or even disregarded.

Did I get you right? Or did I misunderstand?

Replies from: captcorajus
comment by captcorajus · 2009-12-20T22:39:23.792Z · LW(p) · GW(p)

The problem is there is no "subsequent evidence!!" Behavior is not evidence. You must prove that the accused were involved in a crime. Otherwise, lets burn witches.

Footprints in blood? No. Luminol reveal no blood, so footprints in the hallway of a person who lived there means nothing. Likewise, Knox's DNA mixed in droplets of Kercher's blood in the bathroom that they shared is hardly startling. DNA of people who cohabitate mixes all the time whether or not a crime is committed.

There are only TWO pieces of evidence that are said to connect Sollecito and Knox to this crime. The knife and the Bra clasp. An independent report done by the innocence project who directly examined the tester's reports clearly show this "evidence" is hardly proof of anything.

Some wonderful links, that include actual crime scene video shot by investigators and the DNA report compiled by the Innocence Project:

http://vvoice.vo.llnwd.net/e16/4193542.0.pdf

http://www.youtube.com/watch?v=AHleYhBJy8k

http://www.youtube.com/watch?v=gLE4s3jXTVU&feature=player_embedded

http://www.thewrap.com/blog-entry/2354

http://www.youtube.com/watch?v=n71ZJPBq8uk&feature=player_embedded#

And a link that was requested by Braz:

http://www.foxnews.com/story/0,2933,523400,00.html

Replies from: brazil84
comment by brazil84 · 2009-12-20T22:47:13.775Z · LW(p) · GW(p)

"The problem is there is no "subsequent evidence!!""

Of course there is subsequent evidence. For example the fact that Knox and Sollecito were unable to coherently, consistently, and reasonably account for their activities and whereabouts during the time period in question.

That's evidence. And by the way, by "evidence," I don't necessarily mean the same thing as "proof"

Replies from: captcorajus
comment by captcorajus · 2009-12-20T23:02:17.590Z · LW(p) · GW(p)

Ah, but you are under the FALSE assumption that their stories should match or even be cohesive! Investigators will tell you that people's recollections of same events, especially when they are under pressure often vary widely.

Eyewitness evidence is the most unreliable type. Thus, if their stories matched, that may indicate a rehearsal before hand. If they had been involved in the killing do you not think they would have tried to get their story straight? They had 5 days to talk about it.

Thus, in reality, this points more to a lack of guilt that an indicator of it. Here's a fun read:

http://truthinjustice.org/untrueconfession.htm

Anyone with a cursory knowledge of police interrogation techniques knows its just one big "gotcha" game. Confusing the suspect, and undermining their understanding of their reality is basic to "breaking" a suspect. It's a shame that we don't have a video of the interrogation (as required by Italian law). So we only have the police version of events to go by as to what transpired. As you might guess, that doesn't inspire me with a lot of confidence as to the veracity of their statements.

And, hey, while we're on the subject of changing stories: the initial theory of the crime was a ritualistic rite to celebrate halloween, then it was a sex game gone bad, then it was an argument over Meredith's missing rent money, then it was revenge on the "smug," "prissy" girl, then it was "sometimes there is no reason.

Mignini changed his story more times than Amanda and Raffaele put together, but that doesn't seem to bother a lot of people.

It really bothers me.

Replies from: brazil84
comment by brazil84 · 2009-12-20T23:29:49.509Z · LW(p) · GW(p)

Ah, but you are under the FALSE assumption that their stories should match or >even be cohesive!

You are shifting arguments yet again here.

Anyway, there is a distinction between the sorts of inconsistencies which result from typical human error and the sorts of evolution, tailoring, incoherency, convenient amnesia, etc. which result from prevarication.

Knox and Sollecito's stories pretty clearly fall into the latter category.

Replies from: captcorajus
comment by captcorajus · 2009-12-20T23:33:14.188Z · LW(p) · GW(p)

My arguments have remained consistent. You are the one that keeps inserting interpretative observations into this discussion rather than sticking with the objective level facts.

Replies from: brazil84
comment by brazil84 · 2009-12-20T23:44:57.284Z · LW(p) · GW(p)

Your argument keeps changing. First you argued that there was no physical crime scene evidence which would cause one to suspect Knox or Sollecito. Then, when that turned out to be untrue, you argued that the police acted unprofessionally. Then, when I pointed out that was irrelevant you claimed that there was no subsequent evidence against Knox or Sollecito. Then, when I pointed out subsequent evidence you tried to explain it away.

Now you simply accuse me of "inserting interpretive observations" into the discussion. I'm not sure what that means. Maybe it's like the "leap" distinction which other posters tried to draw earlier.

Can you give me two examples of the "interpretive observations" I have been inserting into the discussion?

Replies from: captcorajus
comment by captcorajus · 2009-12-21T00:01:13.684Z · LW(p) · GW(p)

Is it ok if I give you six?

interpretive observations:

(1) A room in the crime scene apartment has been ransacked but no valuables (which were in plain view) were taken;

(2) A window in that same room has been broken with marks suggesting it was broken from the inside;

(3) the same window is on the second floor and can be seen from the street. Further, there is no obvious reason why a burglar would need to get in through an upper floor;

(4) Bloodstains indicate that the victim died with her bra on and the bra was removed a few hours later; and * (This was the opinion of a judge. A Forensic scientist for the defense later refuted this contention.)

(5) When the police arrived at the crime scene apartment, one of the victim's flatmates was standing there with her boyfriend and with a mop and a bucket.

(6) inconsistent stories.

At the end of each of these ask yourself this... how does this connect Knox or Sollecito to the crime?

Objective level facts:

  • Guede's DNA inside kercher
  • Guede's Bloody fingerprints (with Meredith's blood) on kersher's pillow case
  • Guede's feces in the toilet
  • Guede's DNA in Kercher's purse

Ask yourself this. How does this connect Guede to the crime?

See the difference?

I sell cars for a living. My BS detector is off the scale. ;)

The opinion of this case by another attorney (just for fun):

http://www.grahamlawyerblog.com/2009/11/30/issue-of-demeanor-raised-in-amanda-knox-case/comment-page-1/#comment-2988

Replies from: brazil84
comment by brazil84 · 2009-12-21T00:10:04.462Z · LW(p) · GW(p)

It sounds to me like you are claiming that the case against Knox and Sollecito is based mainly on circumstantial evidence.

Is that about right?

Replies from: captcorajus
comment by captcorajus · 2009-12-21T00:40:45.607Z · LW(p) · GW(p)

Exactly, and were Knox and Sollecito the only two people charged in this case you MIGHT have a case (a very poor one).

However, to compound the problem even more, you have another suspect for whom the evidence is overwhelming.

The evidence against Guede is so geometrically out of proportion than that against Knox and Sollecito that it defies logic.

How can that be, if these three people participated in this crime?

The only logical answer is very simply... it can't.

Replies from: brazil84
comment by brazil84 · 2009-12-21T00:52:50.513Z · LW(p) · GW(p)

Exactly

It's still possible to reach reasonable conclusions based solely on circumstantial evidence. For example, I am reasonably confident that OJ Simpson killed his ex-wife based solely on the facts that (1) he is her ex-husband; (2) there is a violent history between them; and (3) he cannot account for his whereabouts around the time of the murder.

Of course here, Knox and Sollecito had no obvious motive to kill Kercher, but the same principle applies, i.e. it's possible to be reasonably confident in a conclusion based solely on circumstantial evidence.

How can that be, if these three people participated in this crime?

Many ways. For example, it is possible that Knox and Sollecito hired Guedo to kill Kircher but did not participate in the actual stabbing. (I'm not saying that this is what happened, I'm just pointing out that it is possible that Knox and Sollecito were involved in the murder even though there was (apparently) none of their DNA on Kercher's body.)

Replies from: captcorajus
comment by captcorajus · 2009-12-21T01:00:56.267Z · LW(p) · GW(p)

I'm sorry Brazl, but now you're just reaching and I'm going to have to call you out on it. No offense. For your argument to have weight it must be based in facts.

My original argument was that had the investigators followed the facts, Knox and Sollecito would not have been (let me add the word "viable" here for clarification) suspects. Your arguments have done nothing to undermine that assertion. If anything, they've only strengthened them, for you have yet to name ONE objective level fact to tie them to the crime.

Even in a circumstantial case, you still need facts to support it.

Replies from: brazil84
comment by brazil84 · 2009-12-21T01:26:48.308Z · LW(p) · GW(p)

I'm sorry Brazl, but now you're just reaching and I'm going to have to call you out on >it. No offense. For your argument to have weight it must be based in facts.

Sure, and the facts suggested a staging/alteration. The killer (or a killer) would have had a strong motive to do so, as well as the best opportunity and means, if he or she was a flatmate of the victim. That's plenty of evidence to make Knox (and by extension Sollecito) a viable suspect.

for you have yet to name ONE objective level fact to tie them to the crime.

See above.

Replies from: captcorajus
comment by captcorajus · 2009-12-21T01:59:17.495Z · LW(p) · GW(p)

Sorry Braz, but that's still Interpretative Observation. The staging/ alteration itself is open to interpretation 1) at trial the defense presented a very viable argument as to why the scene was NOT staged (Filomena had unsupervised access to her room to retrieve some personal items and may have moved things. There's more to it, but I can't specifically remember and I'm too tired to go hunting for links.). and 2) You still must somehow connect Knox and Sollecito to the staging (if such staging actually occurred... which you can't conclusively prove either).

Objective level facts of Guede:

I can conclusively prove that Guede had sexual contact on the night of the murder, he was there, and Kercher bled extensively in his presence.

Good night Braz.

Replies from: brazil84
comment by brazil84 · 2009-12-21T02:04:52.729Z · LW(p) · GW(p)

Sorry Braz, but that's still Interpretative Observation

I'm a little confused. Are you saying that nobody can ever become a viable suspect on the basis of circumstantial evidence alone?

you can't conclusively prove either

Are we talking about conclusive proof or reasonable suspicion?

I'm happy to discuss either one, but please choose one or the other.

Replies from: captcorajus
comment by captcorajus · 2009-12-21T06:05:45.736Z · LW(p) · GW(p)

I apologize, you are correct... I was inferring reasonable suspicion. Conclusively implies 100% certainty and that's hardly ever possible in any case.

I can say that I am 95% sure, Knox and Sollecito had nothing to do with this crime base on the evidence presented. I can say I am 95% sure that Guede Killed Meredith Kercher.

To get an idea of how warped this investigation has been, let's look at a statement from trial judge Judge Paolo Micheli who discounted the "lone wolf" theory and how he arrived at his conclusion:

“I took the opposite approach to that of the defence teams. The lawyers claimed that there was no proof of conspiracy between the three because they didn’t know each other and Kokomani’s testimony wasn’t reliable. They also said that it would have been impossible for them to have organised the crime since they had previous commitments which then fell through. My starting point was the three’s presence in the room where the crime was committed”

i.e. Let's just forget about doubts that Knox and Sollecito knew Guede and were involved in a conspiracy, and just assume that's true. WTF? Innocent until PROVEN guilty is suppose to be part of the Italian justice system, yes?

Begin with a flawed premise, you come to a flawed conclusion.

The judge further states that he discounts the contamination of the bra clasp because Sollecito had no reason to go into that room. Well, what about the three unknown people's DNA on the bra clasp? Who are they?? They are not anyone connected to anyone with the flat as it was compared to all the tenants and their boyfriends. A lab tech's maybe?

Knox and Sollecito are simply not viable suspects in this crime... at ANY point, and the evidence has been blatantly "shoe horned" to make them fit from the beginning. Under close scrutiny and logical thinking it just doesn't make sense... from the beginning days of the investigation, to the closing arguments of the prosecutor who couldn't settle on a theory of the crime.

Replies from: brazil84
comment by brazil84 · 2009-12-21T11:11:04.116Z · LW(p) · GW(p)

I'm still confused. Please just answer my question:

Are you saying that nobody can ever become a viable suspect on the basis of circumstantial evidence alone?

Also, do you agree that the killer (or a killer) would have had a strong motive to do engage in staging/alteration, as well as the best opportunity and means, if he or she were a flatmate of the victim?

Please just answer my questions. It's just two simple yes or no questions.

Replies from: captcorajus
comment by captcorajus · 2009-12-21T22:20:13.828Z · LW(p) · GW(p)

No, I'm not saying that at all!

You are assuming that the assertion of staging is true and there are no alternate explanations... so no.

Here is a neat little compilation I found prepared by "Friend of Amanda" that summarizes the important points nicely. It's easy reading and worth a look

http://www.friendsofamanda.org/files/amanda_knox_case_summary.pdf

Replies from: brazil84
comment by brazil84 · 2009-12-21T22:28:42.825Z · LW(p) · GW(p)

No, I'm not saying that at all!

Then I have no idea what your point is. You seemed to be arguing that Knox and Sollecito were not viable suspects because (initial?) evidence against them was circumstantial. And yet you admit that circumstantial evidence can indeed form a reasonable basis to make somebody a viable suspect.

You are assuming that the assertion of staging is true and there are no alternate >explanations

No I am not. Again, there is a distinction between between evidence and proof.

Replies from: captcorajus
comment by captcorajus · 2009-12-22T14:42:04.485Z · LW(p) · GW(p)

Braz, WHAT initial evidence against them???

Replies from: brazil84
comment by brazil84 · 2009-12-23T00:08:39.802Z · LW(p) · GW(p)

Braz, WHAT initial evidence against them???

For one thing, the fact that blood stains indicated that the victim had her bra removed some hours after she was initially attacked.

For another, the fact that a room in the flat was ransacked but nothing was taken even though valuables were in plain view.

Just because this is circumstantial evidence doesn't mean it's not evidence.

Just because this evidence does not prove Knox's guilt doesn't mean it's not evidence.

Just because there are ways to explain away this evidence doesn't mean it's not evidence.

So please don't respond by arguing either (1) this evidence can be explained away; or (2) that it's circumstantial; or (3) that it doesn't prove Knox's involvement.

Replies from: Tyrrell_McAllister
comment by Tyrrell_McAllister · 2009-12-23T00:56:57.624Z · LW(p) · GW(p)

Braz, WHAT initial evidence against them???

For one thing, the fact that blood stains indicated that the victim had her bra removed some hours after she was initially attacked.

For another, the fact that a room in the flat was ransacked but nothing was taken even though valuables were in plain view.

You didn't establish that these are evidence against Knox and Sollecito. To do so, you must explain why these facts elevate the probability that Knox and Sollecito in particular were involved in the murder.

Replies from: brazil84
comment by brazil84 · 2009-12-23T01:46:21.992Z · LW(p) · GW(p)

Actually I did in a previous post. As noted in that post, someone involved in the murder would have had a strong motive and the best means and opportunity to engage in staging/alteration if he was a flatmate of the victim.

Someone with little or no connection to the victim would not have had much incentive to engage in staging/alteration. And someone who did not live in the flat would have had far less confidence in returning to the crime scene or staying at the crime scene for an extended period of time. Why? Because such a person would naturally worry that another resident of the flat would already be there when he or she returned. Or would return while her or she was there.

So if the crime scene really was altered/staged, the natural suspect is a resident of the flat (and anyone acting in concert with him or her).

Replies from: Tyrrell_McAllister
comment by Tyrrell_McAllister · 2009-12-23T04:03:33.559Z · LW(p) · GW(p)

Okay. I agree that evidence of very time-consuming alterations is evidence that the alterer didn't fear interruption. Now, what was the evidence that the bra was removed "some hours" after the murder?

More pertinent to the point: Was the delayed removal of the bra noticed before Knox and Sollecito were suspects? That is, was it initial evidence, as captcorajus requested?

As for the ransacking, I expect a fake ransacker to be about as likely to fake-steal things as a real ransacker would be to really steal things. Therefore, the failure of the ransacker to steal is not much evidence either way regarding the genuineness of the ransacking.

Replies from: brazil84
comment by brazil84 · 2009-12-23T04:22:02.123Z · LW(p) · GW(p)

Now, what was the evidence that the bra was removed 'some hours' after the murder?

It's on the anti-Knox web site linked to from the "you be the jury" post. If you really want, I will try to dig up a link for it.

That is, was it initial evidence, as captcorajus requested?

I don't know, but in most of my posts I've been using the word "initial" to mean evidence which could be developed from the crime scene without having any particular suspect in mind. "initial" in a logical sense rather than a chronological sense.

If you read back through captcorajus' comments, you will see why that makes sense. But I do agree it's a sloppy use of the word "initial" I suppose it would be better to call it "a priori" evidence.

I expect a fake ransacker to be about as likely to fake-steal things as a real >ransacker would be to really steal things.

I wouldn't. For one thing, if you fake-steal things, you have to take time and energy to dispose of them somewhere and you have to worry that your fingerprints or DNA will be on them. For another, if you have just killed someone and you have never given a lot of thought to staging a crime, there's a good chance it wouldn't occur to you that you actually need to fake-steal stuff to make it look good.

Replies from: Tyrrell_McAllister
comment by Tyrrell_McAllister · 2009-12-23T04:45:54.392Z · LW(p) · GW(p)

It's on the anti-Knox web site linked to from the "you be the jury" post. If you really want, I will try to dig up a link for it.

I was able to find claims that the bra was removed and the body moved "some time" after her death, but not "some hours". Any murderer would have been with the body for some time after the death. [ETA: I also couldn't find what evidence established that the bra had been removed even "some time" after death.]

But, if the murderer stayed for multiple hours, I would consider that to be evidence that the murderer had some confidence that he wouldn't get caught by the residents. Then, I concede, it becomes necessary to consider how likely different people were to have had that confidence.

Replies from: brazil84
comment by brazil84 · 2009-12-23T10:03:03.284Z · LW(p) · GW(p)

I was able to find claims that the bra was removed and the body moved "some >time" after her death, but not 'some hours' Any murderer would have been with the body for some time after the death.

You may be right about "some time" versus "some hours." However, there was also the claim that the victim took quite a while (an hour?) to actually die from her wounds. So it does not seem the murderer would need to have been with the body for some time after the death.

The actual evidence, as I recall, was (1) that there was in impression in the dried pool of blood under the victim from her bra; and (2) there were minimal blood stains on the victim's breasts compared to other parts of her upper body.

Replies from: Tyrrell_McAllister
comment by Tyrrell_McAllister · 2009-12-23T20:30:13.774Z · LW(p) · GW(p)

You may be right about "some time" versus "some hours." However, there was also the claim that the victim took quite a while (an hour?) to actually die from her wounds. So it does not seem the murderer would need to have been with the body for some time after the death.

I would expect any murderer to stay long enough to ensure that the victim was dead. If the victim was alive during the "some time" needed to remove her bra, then that event doesn't add significant probability to the guilt of Knox and Sollecito. Any murderer would want to make sure that the victim didn't live long enough to identify him.

Replies from: brazil84
comment by brazil84 · 2009-12-23T23:16:05.313Z · LW(p) · GW(p)

I would expect any murderer to stay long enough to ensure that the victim was >dead.

I wouldn't necessarily expect that. The murderer might very well just panic and run while the victim lay dying. Indeed, one witness apparently reported hearing a scream followed shortly by running footsteps.

In any event, I would guess that the normal way to make sure somebody is dead is to keep stabbing them until they stop moving. Apparently the victim in this case stopped moving for a while ("quite some time" was the phrased used on the anti-Knox site) before she was moved and her bra cut off.

It's hard for me to believe that a random killer would watch the victim die; watch her motionless for a long enough for her blood to dry significantly, and only then move her and cut off her bra. All the while wondering if somebone else is about to enter the apartment and discover him.

Replies from: Jonathan_Graehl
comment by Jonathan_Graehl · 2010-02-02T21:46:13.258Z · LW(p) · GW(p)

In order for you to believe that the bra must have been removed more than minutes after the stabbings, you must believe one of:

1) the bra was removed in a way that rubbed the material all around her breasts, not cut or unclasped and lifted straight off.

or

2) blood was still dripping significantly from a wound or large smear uphill of the breasts relative to the body's orientation

Evidence I'd accept for 1: smudging suggestive of sloppy bra removal, but with less blood smear than you'd expect from unclotted/dried blood. But I'd need a wide range of lab experiments producing similar marks by smearing different-aged blood in order to know the timeframe.

Evidence I'd accept for 2: pattern of blood flows around the breast may suggest one or more orientations of the body before total drying.

But even if the bra was removed hours later: who says K/S did it, and who says that raises the likelihood of their also stabbing the victim above 1%? I would be interested in what the killer was doing hanging around for hours, if it turns out he did, but that's not impossible either.

Replies from: brazil84
comment by brazil84 · 2010-02-03T00:00:59.724Z · LW(p) · GW(p)

who says K/S did it

In terms of probabilities, if the crime scene was altered, there's a pretty good chance it was done by someone who lived in the apartment. Why? Because a resident of the apartment would have an incentive to do so and would have a much better opportunity.

their also stabbing the victim above 1%?

To me, the question is not whether Knox stabbed the victim so much as whether Knox was involved in the murder.

Replies from: Jonathan_Graehl
comment by Jonathan_Graehl · 2010-02-03T22:15:36.489Z · LW(p) · GW(p)

If I own or rent a residence, and one of the residents is killed there, I agree that I expect some suspicion to fall on me.

I don't agree that I'm therefore very likely to attempt to cover up the crime. In fact, it would be irrational, unless I think the authorities are extremely likely to railroad me out of laziness.

I'd say, if the crime scene was covered up in any way, I'd suspect the perpetrator first.

I read a little more about the case; apparently it was mostly throat-slashing. On the whole, I think it's crazy to suspect that Knox did the slashing, ultimately mostly on the basis of "her behavior was strange" (under extreme duress).

Replies from: brazil84
comment by brazil84 · 2010-02-04T11:08:24.291Z · LW(p) · GW(p)

There's a difference between (1) the probability that a resident will attempt to alter or stage the crime scene; and (2) the probability, given that the crime scene was altered or staged, a resident is responsible.

ultimately mostly on the basis of "her behavior was strange"

Respectfully, I don't think that's a fair summary of the evidence against Knox.

Replies from: Jonathan_Graehl
comment by Jonathan_Graehl · 2010-02-04T22:54:35.803Z · LW(p) · GW(p)

True. There's some physical evidence that can be interpreted as implicating her. I just meant that her prosecution was ultimately caused by a feeling of "her behavior is strange".

Replies from: Kevin, brazil84
comment by Kevin · 2010-02-04T23:02:58.704Z · LW(p) · GW(p)

There was a side-discussion in another thread about how it is quite likely Amanda Knox is a sociopath and that could have made the prosecution think she was guilty and explains some of her strange behavior. But, sociopaths are 5-10% of the population and being a sociopath only marginally increases the probability of committing murder.

comment by brazil84 · 2010-02-05T01:53:57.824Z · LW(p) · GW(p)

If you are saying that the police became suspicious of her at the very beginning because her behavior seemed strange, then you may be right. How should this affect our assessment of the probility she is guilty? I would say it depends on exactly what strange behavior you are talking about.

comment by captcorajus · 2009-12-20T22:13:05.770Z · LW(p) · GW(p)

Whether to suspect her or not isn't the issue. By virtue of her being the victim's roommate, the police should look at her. That's CSI 101.

However, announcing that the case is closed, and that the murder was the result of a ritual sex game gone wrong before you've looked at the forensic evidence seem not only premature, but unprofessional. How can you even come up with such a theory on your interpretation of behavior alone? That says more about the observer than the observed, eh?

For example, much has been made about the "cartwheels" in the police station. Were you aware that Knox was a dancer and practiced yoga? Where you aware that she frequently used yoga positions to relieve stress? Where you aware on the night this was observed she had gone to the station with Sollecito who had himself been summoned by the police? She went voluntarily to the police station. That's not the behavior of a guilty person. No one that knew her was surprised that while she was waiting she would do yoga stretches to relieve tension. Yet the police took this behavior as odd, and that she wasn't properly grieving for her roommate, yet for Knox, this was normal. This is what I'm talking about... making premature assumptions with little corroborative evidence invariably heightens the odds of coming to the wrong conclusion.

I'm saying that the evidence they had on hand at the time does not add up to the conclusion they reached.

Replies from: brazil84
comment by brazil84 · 2009-12-20T22:39:26.680Z · LW(p) · GW(p)

Whether to suspect her or not isn't the issue.

That's different from what you seemed to have been saying before.

Your position now seems to be that the police acted unprofessionally and focused on Knox without a reasonable basis. You are saying that they concluded Knox was guilty without a sufficient basis.

First of all, I am skeptical of your claim. I asked you to provide a cite for your claim about the source of initial suspicion of Knox and you failed to do so. I did my own search and found nothing backing up your claim.

But more importantly, your argument doesn't have much bearing on the ultimate question of guilt or innocence of Knox or Sollecito. If I were arguing that Knox and Sollecito are probably guilty because the authorities concluded they were guilty, then you might have a point, assuming you could substantiate your claims.

In that respect, it's a bit like the OJ Simpson case -- the police may very well have rushed to judgment against OJ. But even so, it seems very likely that he committed the crime he was accused of.

Replies from: komponisto
comment by komponisto · 2009-12-20T23:01:04.446Z · LW(p) · GW(p)

brazil84, I just don't think you have a grasp on how weak the case against Knox and Sollecito is. You've said that the two things that make you think they did it -- the changing stories and evidence of crime-scene-tampering -- contribute 3 or 4 bits of evidence against them. That's quite a small amount, which is easily overwhelmed by :

  • The prior improbability that people like K and S would be involved given that someone else was.

  • The lack of criminal history of K and S.

  • The lack of motive.

  • The lack of connection between K/S and G

  • The lack of any evidence that K and S themselves were at the scene.

I understand that you feel suspicious of Knox and Sollecito based on the reports you've read (the prosecution's narrative does sound like a good made-for-TV-movie), and have a great deal of faith in courts due to your background as a lawyer. In most trials, the defendants are probably guilty. But this isn't a typical case. There are times when you have to look at the object-level facts, and, frankly, do the math. Sometimes, police, prosecutors, and juries are just plain wrong -- stupidly so. This is one of those times.

Replies from: brazil84
comment by brazil84 · 2009-12-20T23:24:59.212Z · LW(p) · GW(p)

That's quite a small amount, which is easily overwhelmed by :

Actually, the 3 or 4 bits was based on the assumption that there was no a priori reason to suspect Knox or Sollecito, such as an obvious motive.

have a great deal of faith in courts due to your background as a lawyer.

Putting aside the issue of my faith in the courts, I have a decent amount of faith in my ability as an attorney to detect BS.

Believe it or not, I have people calling me day in and day out, lying to me and trying to convince me to take their case. For the past few years, I have worked mainly on contingency, so if a prospective client succesfully snows me it's a complete waste of my time and money. As a result, I've gotten pretty good at assessing cases based on limited evidence.

I'm analagous to a professional oddsmaker and most of the folks in this thread are analogous to amateurs telling me I've got my odds wrong. Which is of course possible. It happens all the time that the so-called experts are caught up by amateurs.

Still, while I've never been involved in a murder case, I have heard literally hundreds of stories of people who have denied wrongdoing, evaluated their cases, and then had the opportunity to learn more through discovery and trial.

In this case, it's pretty clear to me that Knox and Sollecito are hiding something important. I've interviewed and cross-examined dozens if not hundreds of witnesses whose stories evolved in a similar fashion to meet evidence against them, often ultimately turning into "I don't remembers" when faced with important contradictions. When further evidence is available, it almost always goes against the stories offered by such folks.

7 or 10 years ago, I would have been a lot less confident that Knox and Sollecito were involved in the murder. But after the experience of having seen hundreds of people lie and attempt to cover up their misconduct, I'm pretty confident that they were involved.

Replies from: komponisto
comment by komponisto · 2009-12-21T07:16:55.563Z · LW(p) · GW(p)

I'm beginning to wonder what evidence could possibly ever convince you that a defendant was innocent. DNA incriminating someone else? We've got it here -- the DNA shows it was Guede. Prosecutorial irrationality and misconduct? Cornucopias full of it: they came up with their theory before knowing about Guede, and didn't drop it once he'd been caught; furthermore, Mignini is under indictment for misbehavior in another case, and is notorious for bizarre conspiracy theories. Et cetera.

All those people exonerated via the Innocence Project? Well, there must have been something suspicious about them, or they wouldn't have been prosecuted and convicted. Why should we be so quick to jump to the conclusion that they weren't involved, just because the DNA points to someone else?

(The irony here is that, were it not for the fact that Guede has already been nabbed, this case would itself be a perfect candidate for the Innocence Project. Given what was used to convict Knox and Sollecito, we may as well still not know about Guede. In which case, the DNA tests showing that it was someone other than Knox or Sollecito would be considered exculpatory, rather than indicative of a three-way conspiracy.)

Actually, the 3 or 4 bits was based on the assumption that there was no a priori reason to suspect Knox or Sollecito, such as an obvious motive.

Write it out. Write out the evidentiary value of each piece of incriminating evidence, together with the values of the various pieces of exculpatory evidence I listed, and do the addition. Make your assumptions transparent for all to see.

I have a decent amount of faith in my ability as an attorney to detect BS.

"My lawyer's intuition tells me" isn't an argument. Beliefs have to be based on evidence. Until you can unpack your intuition and show specifically how the evidence leads to your belief, you might as well be saying you looked into a crystal ball.

Replies from: brazil84
comment by brazil84 · 2009-12-21T11:06:48.046Z · LW(p) · GW(p)

I'm beginning to wonder what evidence could possibly ever convince you that a >defendant was innocent. DNA incriminating someone else? We've got it here -- the >DNA shows it was Guede. Prosecutorial irrationality and misconduct? Cornucopias >full of it: they came up with their theory before knowing about Guede, and didn't drop >it once he'd been caught; furthermore, Mignini is under indictment for misbehavior >in another case, and is notorious for bizarre conspiracy theories. Et cetera.

I'm satisfied that the defendants in the Duke lacrosse case were innocent. And I was reasonably confident of that long before the state prosecutor announced his belief they were innocent.

Well, there must have been something suspicious about them, or they wouldn't >have been prosecuted and convicted.

You are attacking a strawman here. I have refrained arguing that Knox and Sollecito are probably guilty simply because they were charged and ultimately convicted.

Write it out. Write out the evidentiary value of each piece of incriminating evidence,

I will if I can find a block of free time in which I have the motivation to do so.

My lawyer's intuition tells me" isn't an argument. Beliefs have to be based on >evidence.

Again you are strawmanning me. I am saying that as an attorney, I have heard hundreds of people give statements or testify. In situations where (1) peoples' stories have been incoherent/inconsistent in a manner similar to that of Knox; and (2) further evidence became available, that further evidence has virtually always gone against the person's story. Sometimes dramatically so.

Replies from: komponisto, Jonathan_Graehl
comment by komponisto · 2009-12-21T17:19:21.460Z · LW(p) · GW(p)

You are attacking a strawman here. I have refrained arguing that Knox and Sollecito are probably guilty simply because they were charged and ultimately convicted.

I didn't say that's what you argued. I said that if you were to look into the cases of those defendants later considered to be exonerated by DNA evidence, you would likely find grounds for being suspicious of them similar to the grounds on which you are suspicious of Knox and Sollecito. (In fact, I am given to understand that 25% of them actually confessed to the crime.)

I am saying that as an attorney, I have heard hundreds of people give statements or testify. In situations where (1) peoples' stories have been incoherent/inconsistent in a manner similar to that of Knox;

Meaning that they were browbeaten by police into speculating on how their understanding of the situation might have been wrong?

I'm honestly not sure what you're talking about here. One keeps hearing these claims that Knox was "inconsistent", "changed her story", and the like. But the account given at Friends of Amanda seems perfectly convincing to me. From the beginning, Knox insisted she was at Sollecito's. But she was told (falsely) that there was solid physical evidence placing her at the crime scene. This was understandably confusing to her. So after hours of being berated by interrogators, she finally gave in to their pressure by speculating -- upon their prompting! -- about Patrick Lumumba. This doesn't sound like evidence of guilt to me. You say that it does to you because of your experience as an attorney, but you're going to have to do a better job of explaining why -- and more importantly, why it comes anywhere near to trumping the other evidence.

Replies from: brazil84
comment by brazil84 · 2009-12-21T20:32:36.472Z · LW(p) · GW(p)

I didn't say that's what you argued. I

At a minimum, you responded to the argument as if somebody had made it. Since you were responding to my post, it's reasonable to infer that you were attributing that argument to me.

Meaning that they were browbeaten by police into speculating on how their >understanding of the situation might have been wrong?

No.

From the beginning, Knox insisted she was at Sollecito's

During what time period? From approximately what hour to approximately what hour?

comment by Jonathan_Graehl · 2010-02-02T21:31:13.735Z · LW(p) · GW(p)

I am saying that as an attorney, I have heard hundreds of people give statements or testify. In situations where (1) peoples' stories have been incoherent/inconsistent in a manner similar to that of Knox; and (2) further evidence became available, that further evidence has virtually always gone against the person's story. Sometimes dramatically so.

This is stupid. The reason the further evidence turns out to go against them is because they're guilty, not because their stories were incoherent. Don't you think that the vast majority of criminal cases coming to your attention are, by the prosecutor's discretion and incentive, ones where a strong case for the defendant's guilt can be made? That's all the explanation you should need of the phenomena you recount.

Replies from: brazil84
comment by brazil84 · 2010-02-02T23:56:34.819Z · LW(p) · GW(p)

The reason the further evidence turns out to go against them is because they're guilty, not because their stories were incoherent.

No, that's not it. Their stories are incoherent because they are guilty AND the further evidence goes against them because they are guilty.

Don't you think that the vast majority of criminal cases coming to your attention are, by the prosecutor's discretion and incentive, ones where a strong case for the defendant's guilt can be made?

No -- I don't practice criminal law. I practice civil (administrative) law. Perhaps 40-60% of my clients are innocent of the charges against them and I win more than half the time.

Replies from: Jonathan_Graehl
comment by Jonathan_Graehl · 2010-02-03T21:25:43.584Z · LW(p) · GW(p)

I don't think you're allowing much possibility for an innocent who has a suspicious story. You think p(guilty|incoherent) is higher than p(guilty|coherent). I agree. I'm saying that p(guilty|incoherent,criminal prosecution) is very close to the baseline p(guilty|criminal prosecution), because you only see prosecuted those cases where either the defendant is unlucky enough to have a sketchy-seeming alibi, or the direct evidence is strong enough that the alibi doesn't matter.

Since your experience is from criminal cases, my speculation about it was inaccurate; on the other hand, that means that your experience is even less relevant than I thought. Many civil cases go to trial where, as you say, p(win) is nearly 1/2. Not so for criminal prosecutors; they drop cases they won't win.

Replies from: Jonathan_Graehl, brazil84
comment by Jonathan_Graehl · 2010-02-03T22:32:29.039Z · LW(p) · GW(p)

I'd like to back away from my initial response ("this is stupid") to you.

I had understood you to be talking about personally observed frequency of (incoherent and guilty) vs. (coherent and not guilty) in the context of criminal testimony in court. Clearly that's not the case, and you had much more experience with innocent defendants than I anticipated.

Also, I actually understood you to believe that the causation proceeded from incoherent -> guilty, which of course is ludicrous. You later explained that you actually have a roughly correct causal network; my only objection would be in whether you're using the proper frequency for (incoherent and innocent); only if it's nearly zero can you immediately conclude that incoherence very strongly suggests guilt. (otherwise, you have to do the math).

I still hold that amongst criminal defendants at trial, (incoherent and innocent) may be quite frequent, because (coherent and innocent) are almost never brought to trial. But what's important is, amongst criminal defendants, how much higher p(guility|incoherent,trial) is than p(guilty|coherent,trial). I don't actually know precisely what the difference is; I also expect it to be higher, but dwarfed in importance by the additional evidence. I would be extremely hesitant to convict someone solely based on "suspicious cover-up like behavior", but I know that it's happened, e.g. in the case of Hans Reiser.

Replies from: brazil84
comment by brazil84 · 2010-02-04T11:22:29.004Z · LW(p) · GW(p)

I would be extremely hesitant to convict someone solely based on "suspicious cover-up like behavior", but I know that it's happened

I also would be hesitant. And indeed, I don't know if there was enough evidence to inculpate Knox beyond a reasonable doubt. My point in these discussions is that I'm pretty confident she was involved in the murder.

comment by brazil84 · 2010-02-04T11:18:09.785Z · LW(p) · GW(p)

that means that your experience is even less relevant than I thought.

I would say it's pretty relevant. I've questioned hundreds of people who were accused of wrongdoing; come to a belief about their guilt or innocence; and then had an opportunity to see further evidence against them and update my beliefs, so to speak.

As to your point that there is a selection bias in criminal prosecutions, that may very well be the case. I'm not sure what it implies for the Amanda Knox case. I suppose one could argue that the decision to prosecute her is evidence of her guilt. Evidence in the logical sense, not the courtroom sense.

comment by Feh · 2009-12-20T06:53:57.664Z · LW(p) · GW(p)

brazil84's points 1, 2, and 3 are false in my opinion, I have insufficient knowledge about #4 (the allegedly postmortem removed bra) but my reaction is "so what?" and "how does the investigator know the bra wasn't removed post-cut rather than postmortem?"), and here is my take on #5, the mop and bucket...

The allegation that Amanda and Rafael were found with a mop and bucket outside the crime scene apartment is reported on truejustice.org (which has been accused of bias in some of the comments here.) Truejustice.org claims to be paraphrasing a judge's statements about pretrial hearings. This alleged fact apparently did not come up in the actual trial. In the actual trial, Rafael's maid said she found a mop and bucket underneath the sink at his apartment, and said he explained that they had cleaned up some leaked water. The maid testified that there was a clear liquid in the bucket. My wild guess at the truth here is that indeed Amanda and/or Rafael had taken a mop and bucket from Amanda's apartment to Rafael's apartment to clean up a leak, and the maid saw it when she came in the morning (she cleaned around 11:00 on certain days, as I recall.) And then, possibly, and unfortunately for them, Amanda or Rafael brought the mop back to Amanda's apartment shortly before the police arrived. But your guess is as good as mine.

One thing I stumbled across was this comment to a blog:

"There is one simple reason that I believe that Amanda and her boyfriend are both guilty of some involvement in this crime: they were at the apartment the next morning with a bucket of bleach. Please explain away her guilt under this "circumstance.""

I think that's pretty funny, or at least it would be if the freedom of two individuals weren't at stake. No evidence of bleach, by the way.

Replies from: brazil84
comment by brazil84 · 2009-12-20T10:50:18.241Z · LW(p) · GW(p)

brazil84's points 1, 2, and 3 are false in my opinion

Well, do you agree that one of the residents of the flat stated that (1) she left her room without clothing strewn all over it; and (2) there were valuables in plain view which were not taken?

Do you agree that a second floor window was broken? Do you agree that the same window was visible from the street?

In short, I would like to know exactly where you disagree with the points I raised.

And please don't simply offer explanations for these things based on the evidence in its totality. I raised these points to show that there was physical crime scene evidence which supports reasonable suspicion of Knox and Sollecito.

And then, possibly, and unfortunately for them, Amanda or Rafael brought the mop >back to Amanda's apartment shortly before the police arrived

Again, please keep in mind that I raised these points with respect to the issue of whether there were grounds to suspect Knox and Sollecito based on the crime scene evidence.

If you would like to jump to a discussion of Knox's (and Sollecito's) guilt or innocence based on all the evidence in its totality, that's fine, but in that case we need to consider ALL the evidence, which includes evidence that was subsequently developed against Knox and Sollecito.

Replies from: Feh
comment by Feh · 2009-12-24T10:12:28.502Z · LW(p) · GW(p)

I agree that truejustice.org reported that one of the residents stated that she left her room without clothing strewn about and that she left valuables in plain sight that were not taken. I fail to see the relevance to Amanda, especially if the valuables were not clearly valuable or were easily traceable (e.g., the valuables could have been jewelry, which the murderer may have believed risky to fence or believed to be worthless costume jewelry.) Cash was taken.

I agree that a second floor window was broken and that there was easy access to said window from the side/trellis. I fail to see the relevance to Amanda.

You are implicitly referencing the glass-on-clothes argument. I am unmoved by this evidence that the window was broken from the inside because:

  1. Glass fragments could wind up on top of clothes even if the window was broken from the outside. The clothes weren't strewn about before the incident, so, if the glass were broken from the outside then the clothes would have been strewn about after the glass fragments were on the floor, allowing fragments to roll up on top of clothes.

  2. The murderer's objective after the crime seems to have been to delay discovery of the body. The murderer went into the bathroom outside the victim's room to clean himself, then went back into the victim's room, locked the door, and exited through the window. Therefore, even if the window was broken from the inside, which I really, really doubt, it makes sense from the murderer's perspective. Amanda and her boyfriend, on the other hand, sped the discovery of the body by calling the police (although, ironically, other police were already on their way.)

  3. I'm kind of assuming the victim had a European style door lock, which can only be locked from inside, rather than American style door lock, which can be locked before exiting. But if it's true that it was a lock-from-inside style lock, then there is something wrong with the prosecutors. The prosecutors implied there was no way to get in or out of this room through the window (which wasn't true, but never mind), so what happened to the criminal in their estimation? Did he teleport out?

Replies from: brazil84
comment by brazil84 · 2009-12-24T11:12:10.711Z · LW(p) · GW(p)

Cash was taken.

From the room which was ransacked? If so, this would change my assessment of that aspect of the staging issue.

went back into the victim's room, locked the door, and exited through the window. >Therefore, even if the window was broken from the inside

It seems you are under the impression that the ransacking and broken window were in the victim's bedroom. As far as I know, that's incorrect.

Replies from: Jonathan_Graehl
comment by Jonathan_Graehl · 2010-02-02T21:14:04.452Z · LW(p) · GW(p)

Regardless of whether a break-in was actually staged (I don't care), have you ever had your home burgled? I have; they took a few dollars worth of laundry quarters in plain sight, rummaged through some random areas (some drawers, shelves, under the bed, and neglected to take anything else, including electronics, cheap jewelry, and a few hundred dollars cash in a desk drawer.

Replies from: brazil84
comment by brazil84 · 2010-02-03T00:03:36.809Z · LW(p) · GW(p)

Regardless of whether a break-in was actually staged (I don't care), have you ever had your home burgled?

Never (as far as I know).

comment by Shalmanese · 2009-12-13T14:32:57.981Z · LW(p) · GW(p)

Wasn't there a post here a while back that talked about how anyone positing a confidence of 0.999 on something non-trivial was most likely to be suffering from their own cognitive biases?

comment by Morendil · 2009-12-13T10:47:25.646Z · LW(p) · GW(p)

Good points, marred by what appears at first blush like double standards. Why are you willing to selectively discount some DNA evidence while you admit other ?

You say "the supposed Sollecito DNA on Meredith's bra clasp just plain does not count" - what is that "supposed" doing in here ? The FOA site admits that the clasp was shown to carry small amounts of Sollecito's DNA.

Why does it "not count" ? Admittedly, the handling of that evidence may not have been up to the standards normally demanded by the judicial system, but why should that matter to a Bayesian analysis ? All we're interested in as Bayesians is the ratio between P(DNA on clasp|Sollecito guilty) and P(DNA on clasp|Sollecito not guilty).

The defense may well have its own convenient narratives about how Sollecito's DNA "could have been transferred to the fastener in any number of ways" owing to carelessness on the part of the police. Those narratives are just as much noise as all the other noise you've pointed to. The details of US Department of Justice guidelines for forensics are also burdensome details for the defense.

The danger of coming across as arrogant - that is, more confident than your own entanglement with the evidence justifies, not the jurors' or someone else's - is that it provides others with an excuse to abandon the hard work of thinking rationally about the case, and letting themselves be swayed by the affective components: pretty pictures of Meredith or Amanda.

What I liked about your previous post was that, without any rah-rah propaganda about rationality, you outlined a procedure for laying out our current state of (un)certainty while minimizing some of the predictable biases. There was something delightful about the implausibly level-headed discussion thread it generated. We started with an open, almost playful invitation to rationality, in a spirit of inquiry.

Here we seem to be back to a spirit of established truth and advocacy, a spirit of "getting at the teacher's answer" - we even get averaging of the students' grades. I'm expecting the discussion to be more run-of-the mill, too. (Your Postscript is also mildly insulting; if someone is smart enough to arrive at the appropriate level of uncertainty in Knox's guilt, then surely they are smart enough to figure out what to do about it.)

Here, I believe, is the bottom line. Make rationality fun, and people will play along without for a second realizing it's hard work. Make rationality sound like something people ought to have, to be as smart and righteous as you - that's a turn-off.

Replies from: mattnewport, Questor
comment by mattnewport · 2009-12-13T19:30:13.046Z · LW(p) · GW(p)

The Friends of Amanda site claims:

Tests also revealed the DNA of at least three other unidentified people on the bra fastener.

If that is true then it suggests to me that finding Sollecito's DNA as well is not very strong evidence for anything.

Replies from: Morendil, AnnaGilmour
comment by Morendil · 2009-12-13T21:12:53.523Z · LW(p) · GW(p)

Can you explain your reasoning here, in terms of P(other folks' DNA on clasp|Sollecito guilty) vs P(other folks' DNA on clasp|Sollecito not guilty) ?

I can understand how this fact might be "suggestive" of something, but "suggestive" is the same kind of thinking as "suspicious": it's narrative rather than analytical.

Replies from: mattnewport
comment by mattnewport · 2009-12-13T23:47:45.986Z · LW(p) · GW(p)

It seems to me that the prosecution's case against Sollecito relies quite heavily on the evidence they claim proves he was present at the crime scene since they have no other solid evidence against him.

The reasoning used by the prosecution is basically what Jaynes calls the 'policeman's syllogism' in Probability Theory: The Logic of Science. The reasoning is of the form:

  • If A is true, then B becomes more plausible
  • B is true
  • Therefore, A becomes more plausible

Here A is (Sollecito was present at the crime scene) and B is (DNA tests on the bra clasp detected Sollecito's DNA). If we use C to stand for our background knowledge then by Bayes theorem:

p(A|BC) = p(A|C) * (p(B|AC) / p(B|C))

The premise of the policeman's syllogism "If A is true, then B becomes more plausible" takes the form

p(B|AC) > p(B|C)

And by Bayes theorem if this premise is true then:

p(A|BC) > p(A|C)

as stated in the syllogism. Now the significance of the evidence B depends on the magnitude of p(B|C) - the only way finding B to be true can greatly increase the plausibility of A is if p(B|C) is very small relative to p(B|AC). In other words, the prosecution's argument rests on the background probability of finding Sollectio's DNA on the bra clasp being very low relative to the probability of finding it if he were present at the crime scene.

Now it seems to me that the fact that the DNA of several other unidentified individuals (who it is not suggested were present at the crime scene) was also found on the bra clasp indicates that p(B|C) is not so much smaller than p(B|AC). B is only strong evidence for A if DNA on the clasp is much more likely if the person was present at the crime scene but we have several counter examples of DNA on the clasp from individuals who were not at the crime scene so we have reason to doubt that p(B|AC) is much greater than p(B|C) and therefore reason to doubt the significance of the evidence.

Replies from: Morendil, Cyan
comment by Morendil · 2009-12-14T07:24:38.276Z · LW(p) · GW(p)

Now that is analytical.

And by and large I agree with the analysis - that is, I agree that how much weight to give to that particular evidence is determined by your estimates of P(B|AC) and p(B|C).

We may yet disagree on these, but if we do it should be on the basis of models that further evidence can in principle confirm or rule out, for instance whose DNA exactly was found on the clasp - does it match the investigators' ? They were at the crime scene. Contamination of that sort would help (in a Bayesian sense) the prosecution, not the defense.

What I take issue with is to say that something "does not count" when we have a previous commitment to take into account every bit of evidence available to us. Either we use Bayesian standards of inquiry, or judicial standards of inquiry, but we do not cherry-pick which is convenient to a given point we want to make.

comment by Cyan · 2009-12-14T03:26:08.971Z · LW(p) · GW(p)

Very well said.

comment by AnnaGilmour · 2009-12-15T01:45:36.510Z · LW(p) · GW(p)

Check out the blog ScienceSpheres by Mark Waterbury. He discusses at length the issues of negative controls, field controls, and pinpoints the problems with the LCN DNA analysis. One of his key points is that the mistakes in the evidence gathering and testing aren't hit or miss - they are consistent - which reveals a pattern of intention.

comment by Questor · 2009-12-16T02:52:39.345Z · LW(p) · GW(p)

Why are you willing to selectively discount some DNA evidence while you admit other ?

Because the 2 key pieces of evidence should be discounted because they were not arrived at by using the same type of test and were collected differently. All the other DNA testing was done using standard DNA testing in a lab that was nominally set up to do it but which did not always follow all guidelines and procedures and who did not release all data for defense experts to evaluate.

NO DNA that helped the prosecutions case was found initially on the 2 items... the bra clasp and the knife. Regular testing on the rest of the bra had strong findings for Meredith and Rudy. Amanda's DNA was on the knife handle and the bra clasp did have Meredith's as well.

Now the problem comes... the DNA specialist then attempted doing what amounts to Low Count Number (LCN) DNA test which is still experimental in most places and while now accepted in the UK it requires a very specialized expensive lab that must meet many stringent minimum requirements. The tester in this situation had never done this before, the lab was fundamentally lacking in every way to do this test and come up with verifiable, trustworthy data. And yet they did allege that they found MKs DNA or something like it... on the knife... not blood.... no blood on the knife. The DNA would have been in picogram amounts originally and easily contaminated in that lab or elsewhere by the smallest flecks of skin or dust. And there are the same problems with the bra clasp except that along with RS's alleged DNA there are 5 other peoples... unidentified. There can be little doubt that all the DNA and "all" is a very very tiny amount, much smaller than regular standard DNA can reliable even detect as being there...

Add to that no control tests were done and the "evidence" involving these 2 items evaporates. They are rightly to be judged differently from all the other DNA evidence. This looks like a DNA fishing expedition done after no DNA evidence for RS & AK turned up in MK'S bedroom. check these for details http://www.sciencespheres.com/2009/10/methods-of-polizia-pseudoscientificaa.html http://freeaman.001webs.com/pdfs/LCN_DNA_I.pdf http://freeaman.001webs.com/pdfs/LCN_DNA_II.pdf

Replies from: pataz1
comment by pataz1 · 2009-12-16T23:48:20.273Z · LW(p) · GW(p)

the LCN dna test was only done on the knife; the bra clasp was a regular DNA test, i believe.

comment by Unknowns · 2009-12-13T07:43:26.209Z · LW(p) · GW(p)

You're even more overconfident than Eliezer. Even he didn't say that the probability of guilt should be less than 10%.

Also, you ignored the evidence of the scene being rearranged. As far as I can tell, there was substantial evidence of this, and substantial evidence of it being by someone other than RG. This implies substantial evidence that someone else was involved. Even if this doesn't necessarily imply AK is guilty, it definitely implies a probability higher than the original prior (which itself would be much, much higher than the probability you assign of 1 in a 100,000, given the proximity of the persons).

Basically, you are overconfident if you assign less than 10% chance of guilt. And the fact that your opinion is much more extreme than anyone else's doesn't show that you are more rational, but is very strong Bayesian evidence of overconfidence bias on your part, since it is well known that humans are naturally overconfident, not underconfident.

Replies from: brazil84, magfrump
comment by brazil84 · 2009-12-13T14:11:14.103Z · LW(p) · GW(p)

"Also, you ignored the evidence of the scene being rearranged. As far as I can tell, there was substantial evidence of this, and substantial evidence of it being by someone other than RG."

I agree. And also substantial evidence that someone was trying to make it look as though the crime was done by an outsider.

comment by magfrump · 2009-12-13T08:57:56.010Z · LW(p) · GW(p)

The Friends of Amanda site clearly stated that there was no evidence of cleanup and that "cleanup" had only been referenced in passing in the trial, and the prosecution did not pursue the point.

That is, there is not "substantial evidence" of the scene being rearranged, I'm not sure where you're getting that.

Replies from: Unknowns
comment by Unknowns · 2009-12-13T10:24:43.676Z · LW(p) · GW(p)

Yes, it made that claim, but as far as I can see it was wrong. Among other things, the bloodstains on her bra and her body indicated that her bra was removed some time after her death. Even by itself, this implies someone rearranging things. Likewise, luminaled footprints, whether or not they were Amanda's and Sollecito's as claimed, proves that someone cleaned something.

Replies from: McJustice, kodos96
comment by McJustice · 2010-01-02T23:41:36.119Z · LW(p) · GW(p)

Those who say Guede left quickly and therefore was not around to remove the bra, shift the body later and place the cover over her after the blood was dried... forget that she was killed resisting rape and he very likely stayed to complete what he started.

Rudy had plenty of time before he was seen at 2AM in the Disco to first clean up the mess that would have been in the way for what he did next (and by that I mean not only blood but the results of relaxed bowels and urethra) cut off her bra and lay her on her back adjusting where she lay so that he could enjoy what he set out to do originally. That is have sex with her... and he used condoms. And then still time to clean himself up, swab the obvious signs in the bathroom, throw the cover on her and lock the door.

The patrons at the disco who saw him dancing between 2 and 4 AM said he stank very badly....

comment by kodos96 · 2009-12-14T18:00:01.393Z · LW(p) · GW(p)

"luminaled footprints, whether or not they were Amanda's and Sollecito's as claimed, proves that someone cleaned something"

No it doen't. Luminal doesn't reveal blood EXCLUSIVELY. I read somewhere, sorry, can't remember where, that it can also light up things like just sweaty/dirty footprints, no blood necessary.

Replies from: rmattbill
comment by rmattbill · 2009-12-15T07:27:15.965Z · LW(p) · GW(p)

You're absolutely correct. Not only that, but the Luminol footprints specifically tested NEGATIVE for the presence of blood. Every single one of them.

Replies from: pataz1
comment by pataz1 · 2009-12-16T23:51:19.652Z · LW(p) · GW(p)

"If Luminol is used it can destroy important properties of the blood. While it can detect even small amounts of blood, the disadvantage is often that the small amount identified is diluted further by the Luminol solution. For these reasons, Luminol is encouraged to be used as a last resort in crime scene investigations to protect the physical evidence."

Read more at Suite101: Luminol - Chemiluminescent Blood Detector: Forensic Investigators' Essential Tool for Crime Scene Investigation | Suite101.com http://crime-scene-processing.suite101.com/article.cfm/chemiluminescent_luminol#ixzz0Ztn6XLRc

Replies from: Jack
comment by Jack · 2009-12-17T07:57:13.703Z · LW(p) · GW(p)

I Luminoled your bathroom. There were bloody footprints everywhere! Yeah, I didn't find any actual blood, but like you said Luminol can dilute blood.

Who did you kill in your bathroom Pat? How could you do such a thing?! You monster!

Replies from: pataz1
comment by pataz1 · 2009-12-17T23:25:11.204Z · LW(p) · GW(p)

I'm sorry, I didn't realize belittling was in the toolbox of the Rationalist. I'm so glad I found this website so I can update my methods!

Luminol does react with other substances like bleach, but it does so with a different intensity curve; you are talking about chemistry here. According to what I've read, experienced technicians can distinguish the quicker/brighter reaction with bleach from the the slower/longer reaction with blood. I don't know if the technician was asked their professional opinion during the trial as to what they concluded from the reaction.

An understanding of how the evidence was obtained is necessary to judge what the appropriate "weight" is to apply to the physical evidence. You can't discard the DNA on the knife on the basis of procedure and at the same time avoid learning about the procedures used to obtain the other evidence. That would be a contradiction in your rational approach to evaluating the physical evidence. You would be pre-judging the evidence instead of 'letting the winds of the evidence point you to one or several suspects,' which is what Komponisto asks us to do.

I've also made the point in other postings that comparing the results of this rationalist approach to the guilty verdict of the trial is comparing two different things.

I propose that if the original survey were redone but this time ask the probability that the defendants were complicit, you would get a result more similar to the jury's then the results from this blog post.

Disclaimer- I have not yet come to a final judgment on Sollecito & Knox. I play the devil's advocate on all three sides of the case, largely dependent upon what the prevalent view is in the particular forum. (the prosecution, guede's, and knox/sollecito's).

Replies from: Tyrrell_McAllister, Vladimir_Nesov
comment by Tyrrell_McAllister · 2009-12-18T00:09:40.943Z · LW(p) · GW(p)

I have not yet come to a final judgment on Sollecito & Knox. I play the devil's advocate on all three sides of the case, largely dependent upon what the prevalent view is in the particular forum.

Your discourse should be aimed at discovering the truth, not at the bottom line of opposing the local "prevalent view".

Replies from: pataz1
comment by pataz1 · 2009-12-18T03:07:27.099Z · LW(p) · GW(p)

Thanks for the link. While I can't claim to completely understand it on first (and second) read, a few thoughts do come to mind.

I followed a link on that page to the "What evidence filtered evidence" file, and a comment there struck me as being more descriptive of my approach: "If there are two clever arguers in the box dilemma, it is not quite as good as one curious inquirer, but it is almost as good. "

Within most of the forums, they are heavily weighed one way or the other; even neutral forums have the problem that the individuals there are weighed one way or the other. They have arrived at a conclusion, and will argue the rest of the evidence to fit the conclusion. So, I would posit that in many cases you will find that you will have one clever arguer. Is it such a stretch to play the other clever arguer by taking the opposing viewpoint? The Evidence article concludes, "if you are hearing an argument for the first time, and you are only hearing one side of the argument, then indeed you should beware".

Getting back to the Bottom Line theory, my inclination is also to think that Komponisto post actually fits more the 'bottom line' theory then my own responses. In discarding other DNA that would have the 'winds of evidence' blowing towards other individuals, Komponisto references the FOA interpretation of that evidence, which is coming from about as much of a Bottom Line position as you can get. After that assessment, it is only then that we're taken down the rational approach of evaluating the remaining evidence, instead of including the DNA evidence in our evaluation.

Further, Komponisto also states early on that one of the places where you would have the highest signal-to-noise ratio is indeed within the minds of those present; I quote, "the most important evidence in a murder investigation will therefore be the evidence that is the closest to the crime itself -- evidence on and around the victim, as well as details stored in the brains of people who were present during the act"

It was this 'mind' evidence that the police were first presented with, -not- the physical evidence. It was Knox's own statement that placed her at the scene- first as an eyewitness that implicated the bar owner. It was only -after- the physical evidence came back that they found it pointed to Guede instead of Patrick. Under Komponisto's framework, we have to evaluate that evidence almost as equally as we do the physical.

After that, Komponisto's argument that the investigators needed to have an 'inferential path' from Guede to Knox is not as strong (and Komponisto argues that it was the investigators who were at error with this point, not the jury). Knox had placed herself at the scene, and the later stories from Knox & Sollecito were too contradictory and too late; too many questions were raised.

Looking at the two lesswrong articles reference, my inclination is that the 'bottom line' theory applies to people who are unaware that they are taking such a stand. Does it apply when someone deliberately is aware they are taking an opposing standpoint with the belief that that is a path towards a better understanding of the evidence which would ultimately lead one to a "right" conclusion?

I am quite well aware that I take an opposing viewpoint, and in my recent experience it leads to a better discussion around the evidence then agreeing with someone on the conclusion they've arrived to on the evidence. Once people are challenged on their conclusions on their evidence, then the rich arguments come out.

I've gone into other forums and argued extensively that the break-in was -not- staged, and it helped me understand all the reasons people came to the conclusion it was. Applying the american legal definition of 'beyond a reasonable doubt', I have yet to see someone prove 'beyond a reasonable doubt' that the break-in was staged. However, if I were to simply agree with those who believe that, then I would never encounter their rationale on why they came to that conclusion.

In doing so, my own flaws in understanding the evidence are also revealed.

In a final note, in my experiences with my early posts in this forum it seemed I ran into as much people here with the Bottom Line as I have elsewhere . Posts were being voted down as trolls, even simple explanatory posts that provided a technical reference on weighing the evidence. I fail to understand how voting down posts with technical information (that coincidentally provided a contradictory view of the evidence) is "discourse...aimed at discovering the truth".

But I do sincerely appreciate the reference to the other articles; it has given me something to chew on.

Pat

comment by Vladimir_Nesov · 2009-12-18T09:47:30.699Z · LW(p) · GW(p)

I have not yet come to a final judgment on Sollecito & Knox. I play the devil's advocate on all three sides of the case, largely dependent upon what the prevalent view is in the particular forum.

See also: Against Devil's Advocacy.

Replies from: wedrifid
comment by wedrifid · 2009-12-18T10:44:54.159Z · LW(p) · GW(p)

See also: Against Devil's Advocacy.

Thanks for that link Vladmir. I had been planing to write a post on that very subject. People throw around the "I'm being a devil's advocate" as though it is a noble mission rather than crime against reason.

Replies from: pataz1
comment by pataz1 · 2009-12-18T13:41:55.112Z · LW(p) · GW(p)

Frankly, I'm more inclined to agree with brandon's take on it, that its "a social rather than individual process," an aspect the writer of the Against article didn't consider. This is linked at the bottom of the "Against" article.

http://branemrys.blogspot.com/2008/06/on-devils-advocacy.html

Brandon puts forth, "Yudkowsky is right that people who play games by thinking up arguments, however absurd, for a position, are simply being irrational; but this is to no point whatsoever: everyone knows that the devil's advocate is supposed to come up not with any old argument but with good or at least reasonably plausible arguments, arguments with at least some genuine strengths. People play devil's advocate for a reason, not simply in order to start making things up without any rational restraint. There are less elaborate and roundabout ways to play-pretend."

I would point out that online discussion forum are entirely social enterprises, so Brandon's approach at Devil's Advocacy would seem to apply.

Pat

Replies from: wedrifid, wedrifid
comment by wedrifid · 2009-12-19T00:06:35.253Z · LW(p) · GW(p)

I associate claims of 'Devils Advocacy' with a tendency to use whatever clever rhetorical gambits seem most effective. That is, I associate Advocacy, including 'Devil's advocacy' with bullshit. This I hold in low esteem and more so because this kind of debating is highly respected in many contexts. If the impressiveness of arguments was more reliably correlated with quality of arguments this association would be weaker.

ETA: I can only assume that someone objects to the use of 'bullshit' as a descriptor as a distaste for the kind of advocacy I mention is not uncommon here. I tend to use the term to capture a rather precise philosophical concept that we don't have a better word for. The term is 'woo' is the closest approximation.

Replies from: Cyan, mattnewport
comment by Cyan · 2009-12-19T00:14:58.726Z · LW(p) · GW(p)

Personally, I thought you were referring to Frankfurt's theory of bullshit.

Replies from: wedrifid
comment by wedrifid · 2009-12-19T00:19:49.522Z · LW(p) · GW(p)

Well spotted.

comment by mattnewport · 2009-12-19T00:13:54.406Z · LW(p) · GW(p)

It seems not entirely unrelated to your issue with advocacy in this context that advocate is also another word for lawyer...

Replies from: wedrifid
comment by wedrifid · 2009-12-19T00:42:12.923Z · LW(p) · GW(p)

It seems not entirely unrelated to your issue with advocacy in this context that advocate is also another word for lawyer...

I can vaguely recall a conversation here a while back in which someone was advocating a lawyer, judge and bailiff metaphor for rational discourse and also professing devil's advocacy in a nearby context. I suspect I disagreed with him.

comment by wedrifid · 2009-12-18T13:59:36.320Z · LW(p) · GW(p)

I associate claims of 'Devils Advocacy' with a tendency to use whatever clever rhetorical gambits seem most effective. That is, I associate Advocacy, including 'Devil's advocacy' with bullshit. This I hold in low esteem and more so because this kind of debating is highly respected in many contexts. If the impressiveness of arguments was more reliably correlated with quality of arguments this association would be weaker.

ETA: I can only assume that someone objects to the use of 'bullshit' as a descriptor as a distaste for the kind of advocacy I mention is not uncommon here. I tend to use the term to capture a rather precise philosophical concept that we don't have a better word for. The term is 'woo' is the closest approximation.

Replies from: MrHen
comment by MrHen · 2009-12-18T17:09:45.852Z · LW(p) · GW(p)

FYI, not everyone who plays "Devil's advocate" does so on a rhetorical basis. I don't think a gut reaction of "bullshit" is appropriate to the term "Devil's advocate." Either that, or I have been using the term wrong.

When I use the term I mean, "For the sake of the conversation I will defend the position opposite yours." If I defend it with rhetoric, I am not doing a very good job at playing Devil's advocate.

comment by MarkusRamikin · 2011-06-16T12:38:54.001Z · LW(p) · GW(p)

I've wanted to reply here for a good while, so now that I've finally emerged from Lurkdom, I might as well do that. Great post!

Think about what you're doing here: you are invoking the hypothesis that Amanda Knox is guilty of murder in order to explain the fact that she hung up the phone after three seconds.

That was beautiful. Probably the single most important sentence in that whole article, at least in terms of convincing me to your reasoning.

I have to say though, at least one thing you say sounds not just overconfident but blatantly partisan:

known to have had utterly benign dispositions prior to these events".

I wonder how you could know this. If you picked it up from any pro-Knox source of information, it strikes me as a safe assumption that such a source would paint the defendants as angels regardless of the truth.

I'd also like to ask, how necessary to your argument was using that Jesus example? That's preaching to a very narrow choir, even considerably narrower than just "atheists". If that's what you wanted then no problem, but I'm thinking about the lost potential of this article to be persuasive to a more general public. This would be a great article to link friends to if it didn't rely on, not just the tools of rationality, but on specific conclusions shared by (I presume) most lesswrongians.

Replies from: komponisto
comment by komponisto · 2011-06-16T14:46:48.287Z · LW(p) · GW(p)

I've wanted to reply here for a good while, so now that I've finally emerged from Lurkdom, I might as well do that. Great post!

Thank you! Though I would probably write it differently today, it remains my favorite post, in the sense that upvotes and positive feedback on it make me happier than on anything else I've written here.

known to have had utterly benign dispositions prior to these events".

I wonder how you could know this. If you picked it up from any pro-Knox source of information, it strikes me as a safe assumption that such a source would paint the defendants as angels regardless of the truth.

Perhaps, but remember that this isn't something like a political issue, where there are always advocacy websites on both sides. Very few defendants X even have "pro-X sources of information" to begin with -- even if they're privileged (which is not particularly the case of Knox, by American standards). And even when they do, it's often because the case has (or is perceived to have) political implications, and the support is politically-themed. In my view, availability bias resulting from hearing a lot about those types of cases results in an underestimation of the evidentiary value of advocacy on behalf of a defendant like Amanda Knox.

But, remember in any case that we have plenty of anti-Knox advocacy to contrast it with, in addition to the numerous media sources (now including several books) that attempt to be more "neutral" (though often fail). And there just isn't anything bad that anyone can actually find, despite many people trying really hard. The best the anti-Knox folks can do is to come up with their own highly sinister, distorted interpretations of Knox's and Sollecito's personalities, not shared by anyone who actually knows either of them. The absence of objectively negative anecdotes is conspicuous. Meanwhile there are all kinds of good things that have been said about both defendants by people who know them.

I'd also like to ask, how necessary to your argument was using that Jesus example?

Not necessary at all; it was indeed basically an applause light for this particular audience. Of course, there wasn't anything actually wrong about it. And the point I made with it was important: social consensus can't be trusted, or at any rate is very easily screened off.

But yes, the post was definitely targeted specifically at Less Wrong readers, as opposed to the general public. Though I've been surprised at how little negative reaction there has been from outsiders on account of the swipes I took at religion -- virtually none, in fact. The main barrier is a general unfamiliarity with the LW culture of Bayesianism -- but since this post was designed to be a specific application of the LW perspective, I'm not sure how much that could have been helped.

comment by Scott Alexander (Yvain) · 2009-12-13T14:36:02.840Z · LW(p) · GW(p)

No different from the prior, which is dominated by the probability that someone in whatever reference class you would have put Amanda into on January 1, 2007 would commit murder within twelve months. Something on the order of 0.001 at most.

Out of one thousand criminal trials in which the Less Wrong conventional wisdom gave the defendant a 35% chance of being guilty, you would expect to be able to correctly determine guilt nine hundred ninety nine times?

Replies from: Torben
comment by Torben · 2009-12-13T15:48:18.365Z · LW(p) · GW(p)

Out of one thousand criminal trials in which the Less Wrong conventional wisdom gave the defendant a 35% chance of being guilty, you would expect to be able to correctly determine guilt nine hundred ninety nine times?

Maybe I'm missing something, but I think you read that wrong.

komponisto said the evidence should not cause anyone to change the prior probability much. Surely, for people in AK's reference class, the per-year probability of committing a 3-party sex killing is less than 0.001?

I think komponisto quite correctly described the effect of privileging the hypothesis, which might be what caused the LW community to be so much off from his estimate. Everybody seemed to be going backward from assuming AK's guilt at 50-50, whereas komponisto went forward from the background probability.

Replies from: luzhin, gelisam
comment by luzhin · 2009-12-13T21:26:49.566Z · LW(p) · GW(p)

komponisto should not be going forward from the background probabilities because he isn't an experienced investigator with access to the crime scene. he's just a guy reading about evidence on the internet. a more reasonable prior for him to start with is, ''how often are people convicted of murder when they did not in fact commit a murder?'' (there are actual #s for this, too)

when juries sit around thinking, ''is this person guilty or not?'' they assume the investigators working on the case are competent. they assume, quite rightly, that there must be a damn good reason why reasonable investigators couldnt quickly dismiss a hypothesis with such an insanely low prior probability. lesswrong.com readers should do likewise.

comment by gelisam · 2009-12-13T17:56:35.780Z · LW(p) · GW(p)

Everybody seemed to be going backward from assuming AK's guilt at 50-50, whereas komponisto went forward from the background probability.

I think I can see why. komponisto pretended to be a juror following the "innocent unless proven otherwise" mantra and updating on the evidence presented in the court. We, on the other hand, did what komponisto challenged us to do: figure out the answer to his riddle using the two websites he gave us. This being a riddle, not a court, we had no reason to favour one hypothesis over the other, hence the 50-50.

That being said, I did favour one hypothesis over the other (my stated priors were 75/75/25) because at the moment I paused to write down an approximation of my current beliefs, I had already updated on the evidence presented by komponisto himself in his post, namely, that there was a trial against AK and RS.

Maybe the reason why many of us gave so much importance to the fact that those particular individuals were on trial for murder was because it was our very first piece of information; and I don't think it's right for rationalists to do that.

comment by Feh · 2009-12-17T10:57:32.941Z · LW(p) · GW(p)

How much does the choice of words bias peoples' thinking?

"Lone wolf theory" - If you google this term, what comes up is, sadly, the Amanda Knox case, and then terrorist cases like the DC sniper and the holocaust museum shooting. Rudy was not a terrorist, so some people may unconsciously dismiss the likelihood that he was a "lone wolf." And although it's a "theory," the phrase "Lone Wolf theory" sounds like something nutty, whereas it's really the normal scenario in such murders. The onus should lay on disproving this scenario, not proving it.

"Cartwheels" - Amanda Knox is said to have done cartwheels during her interrogation. Cartwheels have a connotation of joy. To prove my point, if you google "cartwheels of joy", it gets 82,400 hits. If the police had chosen the term "gymnastics," then it might be easier to understand why a young girl cooped up for 30 hours might engage in such behavior. Even if she did cartwheels and only cartwheels, she wasn't joyful.

"Foxy Knoxy" - Amanda's character was assassinated by the press long before her trial, and this catchy phrase was responsible for much of it. Ironically, the phrase came from Amanda Knox herself on her Facebook page, according to one of her old friends who stood up for her character.

Words played a powerful role in bias in Amanda's case. I don't think I even need to qualify that as my opinion.

comment by snarles · 2009-12-13T19:04:39.366Z · LW(p) · GW(p)

I'd like to suggest another type of rationality test for this site. The top contributors should randomly make posts that are flat-out wrong to see how they are received; and they should also randomly make legitimate posts under different names.

Replies from: wedrifid, AnnaGilmour
comment by wedrifid · 2009-12-13T23:12:56.607Z · LW(p) · GW(p)

I'd like to suggest another type of rationality test for this site. The top contributors should randomly make posts that are flat-out wrong to see how they are received; and they should also randomly make legitimate posts under different names.

When moving from my real name to this more anonymous persona the responses to my comments were noticeably different. This effect diminished over time. I've actually considered creating mechanisms by which I could make a self-blinded test of the effect of names on reception, but this was more with OkCupid in mind. Perhaps because investigating human psychology is even more fun than the dating itself.

Replies from: Douglas_Knight
comment by Douglas_Knight · 2009-12-14T02:08:53.734Z · LW(p) · GW(p)

When moving from my real name to this more anonymous persona the responses to my comments were noticeably different.

Could you elaborate?

Replies from: wedrifid
comment by wedrifid · 2009-12-14T05:15:59.486Z · LW(p) · GW(p)

Could you elaborate?

Sure. I'll compare what I perceive to be the differences between wedrifid now and, say, < 100 karma wedrifid. The difference in reception was more apparent given that wedrifid didn't have the steep learning curve associated with learning a new micro-culture.

  • Comprehension. Comments by young wedrifid were less likely comprehended than comments of approximately equal quality now. Not understanding people is a signal of high status. It obliges the lower status people to spend effort to second guess your way of thinking and adapt towards your preferred set of concepts in order to communicate with you. This signalling appears to run deeper than an outward display. Higher status people at times seem actually unable to comprehend things that would otherwise be in their grasp, often to their own detriment.
  • Rebuttal. People were more likely to reply with retorts to upstart-wedrifid and, more significantly, provided less or lower quality reasons when doing so. This is to be expected less from high status people and more from people with more moderate status who would like to raise it. (There isn't much point going one up if you have to reach 3 down in order to do so.) I get less replies now that I consider to be absolutely idiotic. Again, I don't think that is just because people generate inane nonsense then decide whether or not to post it by whether they recipient is a newbie or for some reason other reason an easy target (eg. out-of-group or currently being scapegoated). I think the calibration of carefulness is built in to the rebuttal generation system.

Of course, I don't know how much of my perception is just me seeing what I expect to see: normal social behaviour. I also don't think this effect would be sufficient to overshadow a top level post by a renamed Yvain or Eliezer. I would probably just wonder who this amazing new poster was. I still remember Yvain catching me by surprise with that burst of brilliant posting in LessWrong's early weeks. Those seem to be received no worse than Eliezer's would have been if he were still posting regularly. Although come to think of it I may have rejected Wei_Dai's probability posts if I hadn't seen the quality of his other contributions. They are confusing enough topics that I needed to take a while to absorb them before they made sense. Of course, maybe I would have been convinced anyway while trying to write a rebuttal to Renamed_Wei_Dai and realising that he was absolutely right.

I am intrigued somewhat by snarles' other suggestion, the posts by top contributors that are flat out wrong. My dark side wants to suggest that maybe that is the explanation that those anthropic reasoning posts are examples of this! (Of course, a somewhat wiser side of myself reminds me that it is conceivable that I am confused, not Eliezer.)

Replies from: ciphergoth
comment by Paul Crowley (ciphergoth) · 2009-12-14T20:55:52.139Z · LW(p) · GW(p)

Eliezer has made it explicit on several occasions that he never does this. I'm not saying it's necessarily a bad idea, but he doesn't do it.

Replies from: Eliezer_Yudkowsky
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-14T20:58:07.027Z · LW(p) · GW(p)

Aye, and I'll say it again just to be sure. If I want to say something that's not true, I write a story and put it in the mouth of a fictional character.

comment by AnnaGilmour · 2009-12-15T01:41:47.824Z · LW(p) · GW(p)

Another way to go about it is to be contributor-blind. That's what I do.

Replies from: mattnewport
comment by mattnewport · 2009-12-15T02:12:23.183Z · LW(p) · GW(p)

That's a noble goal but I'm sure you're aware that merely having the intent to avoid a bias does not necessarily confer immunity to that bias. Psychological research is full of examples of people still suffering from a bias even when they have been made aware of it and protest strongly that they are not under its influence.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T02:23:05.179Z · LW(p) · GW(p)

I meant, as a general rule of thumb. I code/scan/whatnot for the logic, and then also avert my gaze away from the name. I check the name after I have my response for verification. I like to read things like the Wikipedia list of fallacies so it is an interest of mine. With so much awareness these days of perceptual error (and similar) I find that people over-correct the other way to adjust for it. But I understand that I may be influenced by the name and not know it though I really do block it out of my visual field - as odd as that may seem. I check for those kinds of things as a basic rule and tendency. But I love to be wrong and to be challenged, and I know I have areas to sharpen. Logic is very pleasing to me to the point where when someone points out a problem with mine, I feel pleasure. Okay, enough of my testimonial... I am just happy to find this great site! I love how specific everyone gets. A joy... :)

comment by D_Alex · 2009-12-13T06:54:17.017Z · LW(p) · GW(p)

@OP: you have appealed to rationality in examining this case... then you come up with this:

"1. Negligible. No different from the prior, which is dominated by the probability that someone in whatever reference class you would have put Amanda into on January 1, 2007 would commit murder within twelve months. Something on the order of 0.001 at most. "

The FACTS include 1) the police came to "her house" and discovered a murder victim in one bedroom and 2) she was tried and convicted. You seem to have given these zero weighting in your final calculation.

And this:

"3. About as high as the other two numbers are low. 0.999 as a (probably weak) lower bound."

Did your prior of "0.001 at most" apply to Guede as well?

I offer $50 to the AK defense fund if you can produce a defensible Bayesian probabilities calculation showing how you got from your priors to your final probabilities. A condition is that you must account for the fact that most (let us say 80% for the purposes of your calculation) persons convicted of a crime in a democratic society are in fact guilty of it, and that you use generally defensible assumptions.

Should you try to do so, Less Wrong readers can decide if you have succeeded by voting on the post containing your calculation.

D. Alex

Replies from: None, Blueberry, retired_phlebotomist
comment by [deleted] · 2009-12-13T07:30:18.416Z · LW(p) · GW(p)

While I have a sort of vague sense of disagreement with this comment, I voted it up, because I would be very interested in an example of Bayesian reasoning applied to the real world without having a truckload of given probabilities to work with. In particular, I don't know how one would take into account D_Alex's 80% while also taking into account more specific factors.

Replies from: Tyrrell_McAllister
comment by Tyrrell_McAllister · 2009-12-13T17:13:11.124Z · LW(p) · GW(p)

I had the same reaction. I'm strongly inclined toward the OP's position, but if you're going to excoriate everyone else for failing to "jettison [their] intuitive feelings in favor of cold, hard, abstract calculation", you should provide the actual cold, hard, abstract calculations supporting your own position.

Replies from: komponisto
comment by komponisto · 2009-12-18T20:49:01.655Z · LW(p) · GW(p)

if you're going to excoriate everyone else for failing to "jettison [their] intuitive feelings in favor of cold, hard, abstract calculation", you should provide the actual cold, hard, abstract calculations supporting your own position.

I should have pointed this out earlier, but for the record: "cold, hard, abstract calculation" referred to the willingness to ignore quantitatively weak evidence even though it "feels important" to you; it did not refer to some specific back-of-the-envelope application of Bayes' Theorem.

(And "excoriate" is definitely not the right word here, at least with regard to the LW community.)

comment by Blueberry · 2009-12-13T07:21:50.571Z · LW(p) · GW(p)

A condition is that you must account for the fact that most (let us say 80% for the purposes of your calculation) persons convicted of a crime in a democratic society are in fact guilty of it

I'm curious where in the world you get this "fact". I don't believe that at all (and it seems essentially unverifiable). Also, remember that Knox isn't a random person convicted of a crime: most of them don't make international news. Also, Italy does not have the same rights and freedoms as the US: for instance, they don't have separation of church and state.

Replies from: ciphergoth, D_Alex
comment by Paul Crowley (ciphergoth) · 2009-12-13T09:14:39.947Z · LW(p) · GW(p)

The only test I can imagine is: when a new technique, like DNA testing, comes along, test a random sample of cases to which it is applicable. Unfortunately the cases re-examined are very carefully chosen, so no such information is available.

comment by D_Alex · 2009-12-13T07:32:40.856Z · LW(p) · GW(p)

http://www.ncpa.org/sub/dpd/index.php?Article_ID=14481

Replies from: Blueberry
comment by Blueberry · 2009-12-13T07:46:00.670Z · LW(p) · GW(p)

Thanks for that link. I don't understand why the plea bargain rate is at all relevant. Prosecutors try to dispose of most cases through plea bargaining, and paying a fine may be cheaper than paying legal costs for many people who plead guilty. I don't see any reason why an innocent person would be any less likely to plead guilty.

The innocence project focuses on high-profile murder and rape cases where DNA evidence can be obtained, so it's very non-representative of the criminal justice system as a whole.

Also, this ignores the question of legal justifications and excuses, and other defenses like illegally obtained evidence. If, as a matter of fact, you killed someone, but the evidence was obtained illegally, and you're still found guilty of murder, that's still a wrongful conviction.

Replies from: D_Alex
comment by D_Alex · 2009-12-13T07:56:14.409Z · LW(p) · GW(p)

The part relevant to my earlier post was:

"....even if juries get it right only 80 percent of the time (an assumption at which most sensible scholars would cringe).... But the real wrongful conviction rate is almost certainly lower, and significantly so ... ".

comment by retired_phlebotomist · 2009-12-13T17:05:29.985Z · LW(p) · GW(p)

"I offer $50 to the AK defense fund..."

Has the offer been amended from $50,000 to $50 since last night, or did I just misread it at 1:00 AM?

A shame, because I was looking forward to seeing the attempt.

comment by Seth_Goldin · 2010-06-11T03:03:19.557Z · LW(p) · GW(p)

I know this is an old thread, but for any people just now reading it, I thought I'd pass along this bizarre development.

Replies from: komponisto
comment by komponisto · 2010-06-11T04:29:54.916Z · LW(p) · GW(p)

See discussion here.

comment by komponisto · 2010-02-19T02:17:02.513Z · LW(p) · GW(p)

(Beginning thread for a debate with Rolf Nelson. Others also welcome to comment, of course.)

Okay, Rolf, so to get things started, I'd like to get your numbers out on the table. So, if you wouldn't mind, please tell me, first of all, your current posterior probability estimates for the guilt of:

  1. Amanda Knox
  2. Raffaele Sollecito
  3. Rudy Guede

(I expect we'll mainly focus on Knox and Sollecito, since that's obviously where our main disagreement is; I've included Guede for the sake of comparison.)

Next, I'd like to know your priors for Knox and Sollecito (and Guede as well, if you wish), by which I mean your estimate of the probability that each suspect would commit a crime of this sort, as of (let's say) a month before Kercher's death.

Then, if you could, please list, in descending order of evidentiary strength, the pieces of information most responsible for moving your estimates away from the above priors -- along with, if you wouldn't mind, a rough order-of-magnitude estimate of the strength of each piece of evidence, in terms of likelihood ratios, bits, or bels, whatever you prefer. (Again, I'm most interested in Knox and Sollecito; Guede is optional, at least for now.)

This should allow us to quickly pinpoint our disagreement(s).

Replies from: FAWS, AnnaGilmour, AnnaGilmour, AnnaGilmour
comment by FAWS · 2010-02-22T00:28:48.380Z · LW(p) · GW(p)

Oh, let me play!

(When you made your first post on this issue I found trying to look for unbiased information a terribly frustrating experience so I didn't look for more than 20 minutes, and haven't done any reading on it since, except for a cursory look the the wikipedia page just now. A list of all points that are agreed on by both sides (with sub-points arguing about the relevance of the point from both perspectives, perhaps) would have been very welcome)

Current posterior: not really sure, let's see what I end up with below, but as a starting point:

0.01<P(S) < P(K) <0.2 < 0.8< P (G) < 0.99

Priors for commiting a homicide in a specific month:

P(K)= 4.7 *10^-6 (US homicide rate, assuming being female and a young adult roughly cancel out)

P(S)= 4 *10^-6 (Italian homicide rate assuming young adult males are 4 times as likely to commit murder as average)

P(G)=1*10^-5 (had been implicated in a break-in)

An inhabitant of the top floor of that apartment being murdered in her room in this same specific month (R):

P(R|K)=0.1, P(R|~K)=4.5*10^-6

P(R|S)=0.04, P(R|~S)=4.95*10^-6

P(R|G)=0.0005, P(R|~G)=5*10^-6

Guede's DNA being found all over and inside the victim of a homicide in this same specific month (D_G):

P(D_G|K)=1*10^-4, P(D_G|~K)=6*10^-7

P(D_G|S)=5*10^-5, P(D_G|~S)=6*10^-7

P(D_G|G)=0.6, P(D_G|~G)=1*10^-7

I can't think of any other pieces of evidence that I can treat as effectively independent. Given R and treating the probability of any murders except R as effectively 0: Knox' DNA not being found on the victim (D_K):

P(D_K|K)=0.5 P(D_K|~K)=0.8

P(D_K|S)==0.85 P(D_K|~S)=0.81

P(D_K|G)=0.82 P(D_K|~G)=0.82

Sollecito's DNA being found on bra clasp of the the victim, but nowhere else (D_S):

P(D_S|K)=0.0002 P(D_S|~K)=0.00006

P(D_S|S)==0.001 P(D_S|~S)=0.00005

P(D_S|G)=0.00007 P(D_S|~G)=0.00007

Minimal trances of R's DNA found on the blade of one of the knifes in Sollecito's kitchen possibly matching one of three wounds, along with Knox' DNA on the handle (D_R):

P(D_R|K)=5*10^-6 P(D_R|~K)=1*10^-6

P(D_R|S)=1*10^-5 P(D_R|~S)=1*10^-6

P(D_R|G)=1*10^-6 P(D_R|~G)=1*10^-6

Trying to calculate the probabilities based on those estimates I find that I shouldn't have treated D_G and R as independent either, I get a stupidly high result of 0.9999983 for P(G), and the indirect association with Guede shouldn't make the other two much more likely given that they are already more directly associated with the victim, if anything D_G should make them less likely. The background probability for R should be higher because I forgot to properly account for the fact that there was more than 1 possible victim. Since Guede's DNA and being a room mate alone would already be enough to make Knox almost certainly guilty based on the numbers above and this makes no sense whatsoever I think we can safely say I thoroughly failed this test. I guess the lesson is that making up plausible numbers for various conditional probabilities well outside your intuitive range and then applying them in a basian update doesn't improve your calibration if you have no experience at it at all.

Replies from: komponisto
comment by komponisto · 2010-02-22T02:15:28.674Z · LW(p) · GW(p)

When you made your first post on this issue I found trying to look for unbiased information a terribly frustrating experience

One of the lessons of this exercise, that may be worth stating explicitly, is that there's no "outside referee" you can look to to make sure your beliefs are correct. In real life, you have to make judgments under uncertainty, using whatever evidence you have.

It's not as hard as you (and others) think. Yes, of course, the sources are "biased" in the sense that they have an incentive to mislead if they can get away with it. But what they say is not literally all the information you have. You also have background knowledge about how the world works. Priors matter. If A says X and B says ~X, and there's no a priori reason to trust one over the other, that doesn't mean you're stuck! It depends on how plausible X is in the first place.

I guess the lesson is that making up plausible numbers for various conditional probabilities well outside your intuitive range and then applying them in a basian update doesn't improve your calibration if you have no experience at it at all.

Here's the real lesson: Bayesian calculations are not some mysterious black-magic technique that you "apply" to a problem. They are supposed to represent the calculations your brain has already made. Probability theory is the mathematics of inference. If you have an opinion on this case, then, ipso facto, your brain has already performed a Bayesian update.

The mistake you made was not making up numbers; it was making up numbers that, as you point out in the end, didn't reflect your actual beliefs.

Replies from: FAWS
comment by FAWS · 2010-02-22T03:11:44.324Z · LW(p) · GW(p)

One of the lessons of this exercise, that may be worth stating explicitly, is that there's no "outside referee" you can look to to make sure your beliefs are correct. In real life, you have to make judgments under uncertainty, using whatever evidence you have.

I meant that questions that should have an easily determinable answer, like "Did someone clean the blood outside her room up before the police was called" were unreasonably difficult to settle. Every site was mixing arguments and conclusions with facts. Sure, it's possible to find the answers if you look long enough, but it's much more work than it should be, and more work than I was willing to invest for a qestion that didn't interest me all that much in the first place.

Here's the real lesson: Bayesian calculations are not some mysterious black-magic technique that you "apply" to a problem. They are supposed to represent the calculations your brain has already made. Probability theory is the mathematics of inference. If you have an opinion on this case, then, ipso facto, your brain has already performed a Bayesian update.

The brain doesn't operate with very small or very big numbers, though. And I doubt it operates with conditional probabilities of the sort used above, as far as it operates Bayesian at all I would guess it's more similar to using venn diagrams.

The mistake you made was not making up numbers; it was making up numbers that, as you point out in the end, didn't reflect your actual beliefs.

The point is that I didn't spot that until after I did the calculation, and while I don't usually do much in the way of statistics I intuitively got the simple Bayesian problems like the usual example with false positives in a medical test right before hearing about Bayes theorem for the first time, so I don't think it's because I'm particularly bad at this. If you need to tweak afterwards anyway doing the Bayesian update explicitly isn't very useful as self-control.

comment by AnnaGilmour · 2010-02-21T20:12:26.158Z · LW(p) · GW(p)

This should allow us to quickly pinpoint our disagreement(s).

The disagreement most likely stems from the reliability of the Micheli Report for accuracy and comprehensiveness.

comment by AnnaGilmour · 2010-02-21T20:11:53.324Z · LW(p) · GW(p)

This should allow us to quickly pinpoint our disagreement(s). [I forgot the key command for quoting another comment.]

The disagreement most likely stems from the reliability for accuracy and comprehensiveness of the Micheli Report.

comment by AnnaGilmour · 2010-02-21T20:08:33.533Z · LW(p) · GW(p)

Posterior probability estimates:

  1. 0
  2. 0
  3. .9

Priors:

  1. .01
  2. .01
  3. .5

Is that the sort of thing you are asking? I don't know if I attributed correctly.

Replies from: komponisto
comment by komponisto · 2010-02-21T20:22:31.016Z · LW(p) · GW(p)

Anna: for the context of this, see here.

You may want to remember that 0 and 1 are not probabilities. Also, I must say I don't understand your extremely high prior of 0.5 for Guede. (The evidence against him is such that the prior could be much, much lower and he would still have a very high probability of guilt.)

Replies from: AnnaGilmour, AnnaGilmour, AnnaGilmour, AnnaGilmour
comment by AnnaGilmour · 2010-02-23T01:52:42.745Z · LW(p) · GW(p)

The thing that I am trying to point out is that I believe Amanda and Raffaele were wrongly included in the class called "suspects".

Replies from: komponisto, AnnaGilmour
comment by komponisto · 2010-02-23T02:11:41.480Z · LW(p) · GW(p)

Yes indeed -- our term for that here is privileging the hypothesis.

Replies from: wedrifid
comment by wedrifid · 2010-02-23T02:13:39.591Z · LW(p) · GW(p)

(Although I do find the point more salient when it is described explicitly rather than by reference to jargon. )

Replies from: komponisto
comment by komponisto · 2010-02-23T02:34:20.409Z · LW(p) · GW(p)

Wasn't trying to enforce the use of jargon so much as classify the fallacy.

After all, the point is even more salient when you can relate it to a whole category of error found in many other contexts.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2010-02-23T04:44:10.130Z · LW(p) · GW(p)

I find the term useful. I think it is what a lot of the media has done. Since Amanda and Raffaele are in discussion and named in the theory, there must be something to it and they have equal weights of measure for concern as the third suspect, Rudy. When in fact, they are very lightweight and the (heavy) weight should be attributed to the method by which they became suspects. The term helps me to say "Oh that's what is going on." Like komponisto said, a whole category of error. (Not to mention all the contexts apart from this specific case, the topic at hand, indeed.)

Replies from: komponisto
comment by komponisto · 2010-02-23T05:01:13.206Z · LW(p) · GW(p)

Quite right. It's actually amazing how little attention was paid to Rudy Guede in the media coverage of this case, particularly in the U.S. and U.K. media. (Numerous stories either omitted all mention of him altogether or else referred briefly and vaguely to "a third suspect" -- without any hint about the disparity in evidence.)

comment by AnnaGilmour · 2010-02-23T01:58:36.341Z · LW(p) · GW(p)

I am also pointing out that is a question pertaining to applied situation with a limited scope - the decision to convict or exonerate. For all intents and purposes, relative "knowing" is permissible in a legal case, since we are dealing with human events and activities of a finite nature - a court decision is a discrete (not continuous) matter. After a certain point, probabilties have to turn into decisions.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2010-02-23T02:02:12.187Z · LW(p) · GW(p)

Therefore, I offered 0 in the spirit of Goedel's completeness theorem, yes, at the expense of consistency. Consistency will yield a perpetual motion situation. Completeness is required and can be appropriately reached through reasoning, logic, objectivity, etc. Something can only consistent OR complete. Not both.

comment by AnnaGilmour · 2010-02-21T20:45:07.314Z · LW(p) · GW(p)

In other words, his psychological profile and actions leading up to the murder do not indicate that he was above board and immune from a violent attack, especially an attack with a knife. He was also known around town to go too far in the direction toward harassment of females around town at the clubs and so forth. He was also known to do various drugs including aggression-increasing drugs such as cocaine. He was known to break and enter and steal, and that he carried a ten inch knife "for protection" (his words). It could be argued then that it was a matter of brief time for him to break and enter, steal, and encounter someone indoors in the process as was arguably such in the situation with Meredith, and "defend" himself when caught or interrupted. This is the case that I would start to make as for a high prior.

comment by AnnaGilmour · 2010-02-21T20:40:25.662Z · LW(p) · GW(p)

It is true that a high probability of a prior is not necessary for probability of guilt.

It is also true, however, that it doesn't mean that he didn't have a high prior. I could drop it to .3 though. With the actions in the previous weeks, a case could be made that he was in an escalating pattern of behavior, which is why I gave him a .5 prior.

comment by AnnaGilmour · 2010-02-21T20:36:49.117Z · LW(p) · GW(p)

Thank you. Yes I've seen the post by Rolf Nelson.

I don't understand (though I admit for expediency's sake did not fully read the 0/1 link which I should do if I post here) how there cannot be an absolute for innocence. I didn't assign 1 to Rudy Guede for the reason you mention. But in terms of innocence, we know for example that Princess Diana didn't kill Meredith and that the mayor of Seattle at the time did not kill Meredith, so how can it not be zero? I wrote zero for a specific reason. I wanted it to indicate that gap between reasonability of arrest and no reasonability of arrest. To assign even a small possibility at this point seems inaccurate to me. Although, you make a good point, in actuality, so I would amend them to .001. Is that a proper probability quotient in terms of the question?

Replies from: komponisto
comment by komponisto · 2010-02-21T20:42:53.974Z · LW(p) · GW(p)

Although, you make a good point, in actuality, so I would amend them to .001. Is that a proper probability quotient in terms of the question?

Yes, that would be more reasonable (indeed, it's about where my own estimate is).

Replies from: AnnaGilmour
comment by AnnaGilmour · 2010-02-21T23:24:02.225Z · LW(p) · GW(p)

Is it possible to show that it would be impossible for them to have been participants making it 0? Is there anyone in the world in that class - of 0? Trying to understand the parameters of "probability".

Replies from: RobinZ, Alicorn
comment by RobinZ · 2010-02-21T23:55:35.625Z · LW(p) · GW(p)

I agree with Alicorn - a probability of 0 or 1 can only be legitimately used as hyperbole.

(There's a technical explanation for why to exclude probabilities of 0 and 1, but it assumes you have studied and understood Bayes theorem and know how to think about probabilities in real life in Bayes terms.)

comment by Alicorn · 2010-02-21T23:27:37.893Z · LW(p) · GW(p)

Exactly-0 isn't on the table at all. Close-enough-to-0-that-you-can-represent-it-that-way-without-too-much-disclaiming is reserved for propositions like "a square circle and Batman teamed up to, not kill, but kidnap and replace with a convincing inert android, Meredith". Princess Diana's odds of having killed Meredith are miniscule, but not zero or even compellingly zerolike, compared to those.

Replies from: Jack, AnnaGilmour
comment by Jack · 2010-02-22T00:23:36.070Z · LW(p) · GW(p)

"a square circle".

I don't know if this means I disagree with Eliezer but I'm pretty sure the probability of a contradiction has to be 0 and the probability of a tautology has to be 1. Else really weird things start happening and you can't do deduction. Like, what is the probability of A given A ^ B?

Replies from: RobinZ, Alicorn, wedrifid
comment by RobinZ · 2010-02-22T00:32:51.594Z · LW(p) · GW(p)

*cackles evilly and cracks metaphorical knuckles*

The circle is defined as the locus of points an equal distance from a center on a plane. A square is defined as a regular quadrilateral - i.e. a shape with four sides of equal length separated by four angles of equal magnitude. If you allow that "distance" may be generalized) to be applicable to other geometries than Euclidean...

...what is the shape of a circle on a chessboard, where "distance" is measured by the number of king-moves?

I believe this is a useful object lesson in the difficulty of constructing properly impossible propositions.

Edited to make the square have four sides, not three. What was I thinking...?

Replies from: Jack
comment by Jack · 2010-02-22T00:42:34.527Z · LW(p) · GW(p)

And when you superimpose a middle finger onto Reimannian space...

Edit: But upvoted because it is always good to get this reminder.

comment by Alicorn · 2010-02-22T00:39:55.942Z · LW(p) · GW(p)

Something can be metaphysically/logically impossible without it being okay to assign exactly-0 to it. Epistemic probability is what we're really representing here - I mean, even something as uncertain-to-me as the current weather conditions in the red spot on Jupiter is exactly one way. But it's not useful to represent that single-ness of weather conditions because I can't access them. I similarly can't usefully access absolute epistemic certainty about even simple math and logic. I'm a broken machine; I cannot handle perfect surety.

Replies from: Jack
comment by Jack · 2010-02-22T03:08:53.710Z · LW(p) · GW(p)

It isn't that simple. Most of the results we get from Bayes theorem we get by deduction. For example, the Dutch book argument, the most common justification given for Bayesian epistemology in the first place, relies on deduction. So does nearly every other important result we get from Bayes theorem. So when you say to someone: take this evidence and act rationally that may imply that that person not get her deductions wrong. This is why, afaict most Bayesians assume logical omniscience. See here. Apparently there have been attempts to weaken logical omniscience and maybe someone here has one in mind... but I haven't heard it. Obviously it is that case the humans, as a matter of psychological fact can screw up deduction. But this is basically like saying that as a matter of psychological fact humans aren't perfect Bayesian rationalists. The whole theory isn't supposed to be descriptive, it is an ideal to strive toward.

comment by wedrifid · 2010-02-22T01:17:51.865Z · LW(p) · GW(p)

I have also seen Eliezer tempted to consider a '0' probability in response to a 'divide by infinity' situation. (I think there is a 'mathsy' way to represent that kind of '0'.)

Replies from: kpreid
comment by kpreid · 2010-02-22T01:53:09.494Z · LW(p) · GW(p)

That's called a limit). What's special is not the “zero” but the “infinity”: you don't talk about a value “infinity” (attempting to have one causes you to lose various other useful properties), but rather that as some input increases without bound, the output approaches zero.

“The limit of 1/x as x approaches infinity is zero."

Replies from: AnnaGilmour
comment by AnnaGilmour · 2010-02-23T01:47:46.832Z · LW(p) · GW(p)

The concept of limits is a great way to look at this. A limit is a thing unto its own, a complex statement indicating, confirmed as much as is humanly possible.

Another notion is what Goedel brings to the table. His contribution of something being consistent or complete is relevant.

comment by AnnaGilmour · 2010-02-21T23:38:00.329Z · LW(p) · GW(p)

Well, it is quite fascinating that no one gets a 0 probability. Just to ask, does Meredith get a 0 probability? I will move past understanding the exclusion of 0. I just want to make sure I understand. Anyway, when I say 0, I understand it to mean functionally 0, which is the same as .0000000001, which is also functionally 0, correct? Thank you for you patience.

Replies from: Alicorn
comment by Alicorn · 2010-02-22T00:34:53.489Z · LW(p) · GW(p)

Meredith could have committed suicide. She's probably more likely to be responsible for the death than Princess Diana. And she's much more likely than the team of Batman-and-square-circle.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2010-02-22T01:02:56.938Z · LW(p) · GW(p)

Were there any fatal wounds that she could not have inflicted?

Replies from: Alicorn
comment by Alicorn · 2010-02-22T01:23:16.019Z · LW(p) · GW(p)

Well, maybe she had superpowers. Or was killed by her time-traveling past self. When you get to probabilities this low, boy do you ever get to make shit up.

Replies from: wedrifid
comment by wedrifid · 2010-02-23T02:11:33.731Z · LW(p) · GW(p)

Maybe she was killed by her time-traveling future grandaughter. I was tempted to rule it out based off the anthropic principle (I don't expect to exist in a world in which someone was killed by someone who wouldn't exist if the victim was killed). But come to think of it I haven't assigned 0 to specific operational mechanisms behind time travel.

comment by Psychohistorian · 2009-12-13T06:21:11.279Z · LW(p) · GW(p)

Negligible. No different from the prior, which is dominated by the probability that someone in whatever reference class you would have put Amanda into on January 1, 2007 would commit murder within twelve months. Something on the order of 0.001 at most.

Suppose it were somehow revealed to you that three people had in fact committed the murder. Would you still maintain that K and S are no more likely to have been involved than anyone else in the relevant reference class? If not, doesn't this suggest that this quoted bit is an overstatement?

That's a genuine question; I haven't fully thought that concept through.

Replies from: komponisto
comment by komponisto · 2009-12-13T06:46:48.415Z · LW(p) · GW(p)

Suppose it were somehow revealed to you that three people had in fact committed >the murder. Would you still maintain that K and S are no more likely to have been >involved than anyone else in the relevant reference class?

There is a proximity effect, just as in the actual situation K's probability is slightly raised by the fact that a killing occurred in her house (and S's is in turn raised by his intimacy with K). But the evidence against G utterly destroys her explanatory value, and brings her probability back down to the prior.

If not, doesn't this suggest that this quoted bit is an overstatement?

No, because this is my posterior probability after taking into account the evidence against G.

Replies from: Psychohistorian, Unknowns
comment by Psychohistorian · 2009-12-13T06:58:35.463Z · LW(p) · GW(p)

But the evidence against G utterly destroys her explanatory value, and brings her probability back down to the prior.

This is true in reality, not in my hypothetical. If it were a fact that three people had been involved, as posited, the evidence against G would not explain anyone else away on its own. I'm using a counterfactual to attempt to show that your claim that there's no special evidence of her guilt is false.

You've stated: [A] P(Knox is guilty) = P(Random person from relevant social circle is guilty). It seems to me that [B] P(Knox is guilty; given multiple killers) > P(Random person from relevant social circle is guilty; given multiple killers). Assume [B] is true. The additional specification does not point to K, it only says that people other than G are guilty. Therefore, [A] should be false. So, I'm assuming you would take issue with the truth of [B], or else with my reasoning, and I'd be curious as to how and why either way.

Replies from: magfrump, komponisto
comment by magfrump · 2009-12-13T08:54:24.146Z · LW(p) · GW(p)

the issue at stake is P(multiple killers) being very small, and P(knox guilty) - P(random person guilty) is less than zero due to the P(G guilty).

Or at least that is how I would weight them.

Replies from: Unknowns
comment by Unknowns · 2009-12-13T10:30:12.911Z · LW(p) · GW(p)

Given that someone was killed, the probability of multiple killers is not "very small", according to statistics. Definitely not more than 50% but definitely substantial (as I stated in another comment.)

comment by komponisto · 2009-12-13T07:17:57.694Z · LW(p) · GW(p)

[A] is only true given the evidence against G. Not knowing that evidence, we would have P(Knox) > P(random peer) by proximity.

Replies from: michaelsullivan
comment by michaelsullivan · 2009-12-16T14:59:57.482Z · LW(p) · GW(p)

This is entirely wrong. The evidence against G should modify both P(Knox) and P(random peer that is not G) downward.

Proximity should keep P(Knox) > P(random peer) unless there is evidence specific to Knox which lowers her P (i.e. a good alibi).

Your statement about proceeding from the physical evidence and ignoring other things is a heuristic. The fact is that some random suspicious behavior by K is evidence against K, it is just extremely weak evidence. Let R = random suspicious behavior by K. I contend that P(K|R) > P(K|^R). Your arguments that many people do R all the time and are not murderers address the strength of the evidence, but do not address the sign, unless you wish to contend that people who engage in R are less likely or equally likely to be murderers than people who do not. You have made no such argument.

It's clear that the evidence against K should be overwhelmed by the evidence against G, given that no solid connection was established between G and K. But it isn't zero evidence, it is merely very weak evidence.

You have established a safety heuristic to keep yourself from overvaluing weak evidence, but your safety heuristic has it's own shortcomings, because it has caused you to give it zero weight, which is obviously wrong.

Replies from: komponisto, komponisto
comment by komponisto · 2010-03-02T15:37:48.268Z · LW(p) · GW(p)

This is entirely wrong. The evidence against G should modify both P(Knox) and P(random peer that is not G) downward.

No, it is most certainly not "entirely wrong", if it is even wrong at all.

Explanatory value is the only attractor of probability: there is nothing that can possibly raise P(Knox) except improbable facts that require explanation (where the amount of probability flow as a function of the improbability of the explanandum is governed by Bayes' Theorem).

In this case, virtually all of the improbability of the data is contained in the mere fact of Kercher's death. But that fact is entirely and adequately explained by the actions of Rudy Guede; the evidence against Guede completely obstructs -- screens off -- the probability flow toward Knox.

That is the argument made in the post. Nowhere did I say that evidence of Guede's guilt is evidence of Knox's innocence, in the sense of lowering P(Knox) to below the prior. But the evidence against Guede absolutely is evidence against the hypothesis that Knox killed Kercher without Guede -- which is most of the Knox hypothesis-space (and thus where most of the probability flow toward Knox arising from Kercher's death was concentrated)!

(This point is especially important in view of all those comments from people saying that "the prior" should (already) take into account the fact that Kercher was killed. Well, if that's your prior, then it most definitely is lowered by the evidence against Guede!)

When you make a statistical argument of the form "well, a homicide was committed, so there's some probability of multiple attackers", you're starting from a position of ignorance of the details of the case, and computing an expected probability over all the various scenarios where there exists evidence of multiple attackers. But here, we know the details of the case, and we know that there is scant evidence of anybody but Rudy Guede being guilty (at least, we do if we're capable of telling strong evidence from weak).

Finally, these comments of yours

It's clear that the evidence against K should be overwhelmed by the evidence against G, given that no solid connection was established between G and K. But it isn't zero evidence, it is merely very weak evidence.

You have established a safety heuristic to keep yourself from overvaluing weak evidence, but your safety heuristic has it's own shortcomings, because it has caused you to give it zero weight, which is obviously wrong.

represent nothing but uncharitable pedantry -- the Bayesian analogue of my pointing out to you that "its" in the above sentence should be spelled without an apostrophe. It's not, and has never been, a question of whether P(Knox) is literally greater than P(random peer); the question is whether it's noticeably greater. If it makes you happy, I'm willing to concede that the evidence in this case raises P(Knox) from 0.001 to something like 0.0034. But that scarcely makes my argument "wrong", let alone "entirely wrong".

So that's why I have downvoted your comment: because, while it sounds all learned and serious, like you have an important probability-theoretic lesson to teach, it reduces to nothing more than a snark. (In fact, it may have been the exact comment I was thinking of when I wrote this.)

Seriously: "entirely wrong"? WTF?

Replies from: michaelsullivan
comment by michaelsullivan · 2010-03-25T18:06:04.692Z · LW(p) · GW(p)

since you appear to still be watching this thread, it seems worth a reply even 3 months later.

Clearly "entirely wrong" is too strong and unnecessary verbiage in any case. I admit it did not even occur to me that you were using "=" to mean only "essentially equal in absolute terms".

Note, my comment was referring only to your response to Psychohistorian, not your general argument about why P(Knox) is very small given the information presented at trial, with which I agree wholeheartedly.

I apologize for my confusion. Here and in a few other comments, you seemed to be asserting not merely that the strong evidence against G put so much probability mass into P(G) that the differences between P(Knox) and P(random peer) became much too small to care about in absolute terms, but that it somehow changed the relative dynamic between P(K) and P(rp). The fact that neither probability was worth worrying about in legal terms doesn't change the '>' vs. '=' question, and that's the only thing I was responding to there. I also suspect the distinction matters in practice in rare cases, so I saw it as important enough to be worth picking the nit.

comment by komponisto · 2009-12-16T19:05:18.051Z · LW(p) · GW(p)

Your statement about proceeding from the physical evidence and ignoring other things is a heuristic.

It's clear that the evidence against K should be overwhelmed by the evidence against G, given that no solid connection was established between G and K. But it isn't zero evidence, it is merely very weak evidence.

Yes, I agree. Did you read this discussion before making this comment?

comment by Unknowns · 2009-12-13T08:06:09.681Z · LW(p) · GW(p)

The percentage of murder cases that involve multiple murderers is relevant to the idea that the evidence against G "brings her probability back down to the prior," and this percentage is much higher than you think it is (i.e. it is higher than 1% of cases, and this is enough that AK's probability will definitely not go back to the prior. In fact it seems to be in 10-20% of cases),

Replies from: rmattbill, komponisto
comment by rmattbill · 2009-12-15T00:39:39.267Z · LW(p) · GW(p)

That may be true, but many cases of wrongful conviction involve multiple innocent defendants. The Norfolk Four is a perfect example. At one point the police suspected SEVEN men of the attack, even though the coroner said there was only evidence of an attack by one person. In the end, it turned out one person, a known rapist, had committed the crime, but not before four of the innocent served over a decade in prison.

For those who criticize Knox pointing the finger at Lumumba, again, look at the Norfolk Four case where the first suspect, innocent, wrongfully accused a friend, who then wrongfully accused several friends, who then wrongfully accused several of their friends! It might be impossible to understand the mindset that leads to something as wrong as falsely accusing someone else, but it's happened to a lot of people, and normally they are treated with far less scorn than has been poured on Knox by her critics.

comment by komponisto · 2009-12-14T07:37:34.784Z · LW(p) · GW(p)

This is accounted for in my updated estimates.

Replies from: Unknowns
comment by Unknowns · 2009-12-14T07:59:15.954Z · LW(p) · GW(p)

Ok, but given your updated estimates, it is consequently unreasonable to just dismiss psychological and interpreted physical evidence (i.e. bloody footprints, crime scene rearrangement and so on). Whether this is actually so or not, it is very possible that these things could add together to give enough evidence to say that someone is probably guilty; going from a 1% to a 99% chance does not take an extremely large amount of evidence.

And this seems to imply that an hour on the internet does NOT beat a year in the courtroom. To know whether this is true or not you would actually have to know the evidence in more detail. For example it does seem that even in Judge Micheli's report there is a good deal of detail that has been generally unreported in English.

Replies from: komponisto
comment by komponisto · 2009-12-14T08:07:26.987Z · LW(p) · GW(p)

Ok, but given your updated estimates, it is consequently unreasonable to just dismiss psychological and interpreted physical evidence

I don't see why this kind of stuff is any more powerful than its counterparts on the other side: K & S's benign personalities, lack of criminal history, lack of motive, etc.

Replies from: Unknowns
comment by Unknowns · 2009-12-14T08:15:07.125Z · LW(p) · GW(p)

That may be true. I read (I didn't pay attention to the source, it could be just a rumor for all I know) that AK sent an email to a friend, shortly after coming to Italy, saying that she had convinced a stranger to have sex with her on a train. If true that would show a dangerous kind of behavior, even though not criminal. Assuming she might be guilty (for the sake of argument) the most likely explanation would be that they were "playing around" and things got out of hand, not that anyone ever was planning to murder someone.

In any case it seems my last point stands: the evidence as it has been presented to us may be unpersuasive but that doesn't mean that the same kinds of evidence couldn't become persuasive in principle, and this may be exactly what happened in the trial.

comment by bigjeff5 · 2011-03-02T18:33:25.208Z · LW(p) · GW(p)

I'm ashamed to say I failed this one, and badly.

I'm new to the Way of Bayes, and I've been reading the sequences regularly (that's why I'm on this post, actually) and thinking I've been doing pretty well, but this illustrates that I have a long, long way to go.

I did do a whole lot better than the jury in this case, such that I would never have convicted Knox and her boyfriend, but I still came away with about a 60% probability of their having been guilty, with Guede at >95%.

I started with the pro-guilty website, and thinking back I clearly privileged their hypothesis. In fact I had only assigned about an 80% probability that they were guilty after reading their evidence, which would not have been enough to convict. They made scant mention of how little DNA evidence was actually used to convict them (even calling the braw-clasp significant, damning evidence), and they certainly didn't compare this to the massive amounts of DNA evidence found for Guede. In fact they made it sound as though the evidence was equivalent.

I then updated based on the pro-defense website, down to 60%, a clear case of anchoring. Had I considered the defense's evidence from a fresh perspective there is no way I could have come away with the estimate I did. The overwhelming DNA evidence against Guide should have relegated all other evidence to almost negligible importance. Everything else was unreliable, and I did not treat it as such even though in my mind I even thought that it was unreliable.

A good analogy for the DNA evidence compared to everything else would be like trying to star-gaze at high noon - the light from the sun overwhelms the starlight because the starlight is far, far too weak. Likewise the circumstantial evidence was far too weak to be of any importance when compared to the DNA evidence.

Replies from: komponisto
comment by komponisto · 2011-03-04T03:57:58.006Z · LW(p) · GW(p)

I'm ashamed to say I failed this one, and badly...this illustrates that I have a long, long way to go.

On the other hand, you'd be surprised at how difficult it is for people to understand this even after seeing the explanation. While of course it's always preferable to get things right on the first try, the fact that you saw it so clearly after reading this post places you in a high percentile for learning speed.

(I know whereof I speak here, because I've spent some time arguing about this in other parts of the internet, only to be dismayed by the true extent of people's ability to clack. Heck, even here in the comments section of this post there are some pretty confused comments with depressingly high scores.)

I think your analysis is excellent, and is an admirable example of "cognitive debugging". This part in particular is worth dwelling on:

Everything else was unreliable, and I did not treat it as such even though in my mind I even thought that it was unreliable.

It is really difficult for people to discount information, and to actually update on evidence of the form "that information may not be reliable", rather than treating it as an "opposing argument" to be rationalized away, or simply forgetting it altogether. Something like the bra clasp provides an example of this: people hear about it, and decide that Sollecito is guilty. Then, when they hear the defense argue that it's unreliable, they mentally dismiss it as "the defense trying to poke holes in the prosecution's case". They may respect the social obligation to provide some sort of answer to the defense's arguments, but they don't consider that the defense arguments should actually impact their belief about whether Sollecito is guilty; the belief-formation process was over and done with at the first stage!

It's not that they explicitly, consciously think like this, of course; rather, they have just failed to fully incorporate the "rules" into their unconscious belief-generating system. The third and fourth virtues are hard.

I like the star-gazing-at-noon analogy, and may use it myself in the future.

Replies from: bigjeff5
comment by bigjeff5 · 2011-03-04T05:07:27.682Z · LW(p) · GW(p)

I think your analysis is excellent, and is an admirable example of "cognitive debugging". This part in particular is worth dwelling on:

Everything else was unreliable, and I did not treat it as such even though in my mind I even thought that it was unreliable.

That's what upset me the most. I made a special note of it, in order to give it a very low weighting, yet it was still a major factor in my assessment. It had to be, because the prosecution's case hinged on it.

I think next time I notice something like that I will have to assign it a specific weight as soon as I decide that it should be given a low weight. Instead I just labeled it as "weak" in my head and moved on.

So when I think "that's likely true" I should stop and consider what the actual number is that I would assign to it. This would help considering in spotting cases where I assign more than 100% total probability to an outcome. If I am thinking it is 70% likely that they are guilty and 60% likely that they aren't, there is an obvious problem. If I don't assign any numbers until I'm finished looking at the problem then I'll never spot this error, as I'll simply calculate not-guilty likelihood from the guilty likelihood.

Much to think about and much to learn still.

comment by komponisto · 2010-01-15T20:59:34.837Z · LW(p) · GW(p)

A flurry of more recent comments, (concerning in particular the nature of evidence), plus some private message correspondence, provides me with an excuse to make what are probably somewhat-overdue comments succinctly summarizing the main points of this post, addressing the most important issues and objections raised by others, and tying up some loose Bayesian ends.

Objections raised to my arguments seem to fall mostly into the following categories:

(1) Bayesian pedantry: pointing out that weak evidence is distinct from zero evidence, that rational evidence is distinct from legally admissible evidence, arguing that I chose "the wrong prior" (as opposed to just coming out and accusing me of failing to update on piece of evidence X), etc.

(2) Claims that I am too dismissive of psychological evidence.

(3) Object-level arguments from a few people who (still) think there is a significant chance Knox and Sollecito are guilty.

Here are some general responses, divided up into three separate (threaded) comments for ease of reading (and possibly replying):

(1) Bayesian pedantry.

In the first version of the post, when I wrote "there is for all intents and purposes zero Bayesian evidence that Amanda and Raffaele are guilty", I thought that "for all intents and purposes" was enough of a disclaimer; but really, of course, what I should have written was: "there is for all intents and purposes zero net Bayesian evidence...". Obviously there is some (weak) evidence of K and S's guilt; but (I claim) it is cancelled out by the evidence of their innocence to such an extent that the posterior probability is close to (not necessarily literally equal to) the prior probability.

And yes, by "prior probability", I am entitled to mean the probability that Amanda Knox would commit murder, rather than the probability that Amanda Knox would commit murder given that a murder occurred in her house. I have not neglected to take into account the latter information, and indeed, the fact that her housemate was murdered obviously raises the probability that Knox is guilty of something to a level significantly above the background prior. However, this probability is lowered again by the information that Guede committed the murder -- and this is true despite the fact that evidence of Guede's guilt is not itself evidence of Knox's innocence. As Eliezer put it,

the fact that we know Guede did it means that there's no unexplained murder around for Knox to be convicted of.

The Bayesian structure of this inference is simple enough. Let H be the hypothesis that Knox killed Kercher, and let E be the datum that Kercher was killed. Obviously, H and E are not independent; in fact, H strictly implies E, which means that P(H&E) = P(H). Thus P(H|E) = P(H)/P(E), which is larger than P(H). Now, however, let E be the datum that Kercher was killed by Guede. Then H and E are much closer to being independent, i.e. P(H&E) is only slightly larger than P(H)P(E), which means that P(H|E) is close to P(H)P(E)/P(E) = P(H). As I argued in the post, this is Occam's Razor at work: P(H&E) = P(H)P(E) << P(E).

To those who gasped at my dismissal of the DNA evidence against Knox and Sollecito when it is my solemn Bayesian duty to consider all available information, I would put it that Bayesian rationality is supposed to be more accurate than legal reasoning, not less. The kind of legal rules of evidence that would come into play here exist because of known biases people have toward convicting defendants (others, not relevant here, exist as a reflection of society's willingness to let a few culprits go free in order to maintain a certain incentive structure on police and prosecutors). Thus, if when you put your Bayesian goggles on, you suddenly find that defendants are looking more guilty than they used to, you're probably doing something wrong. In any case, dismissing evidence is not an illegal Bayesian move; it simply constitutes an assertion that the likelihood ratio for the information in question is close to 1. In other words, the evidence is very weak. Which probably has something to do with why it might not be admissible in court.

Replies from: komponisto
comment by komponisto · 2010-01-15T21:01:58.721Z · LW(p) · GW(p)

(2) Claims that I am too dismissive of psychological evidence.

Some folks appear to have misunderstood me as arguing that psychological evidence can be dismissed out of hand by its very nature, or that Amanda Knox shouldn't have been questioned by police despite being Kercher's roommate. Obviously, neither is the case. First of all, psychological evidence, strictly speaking, is physical evidence. In fact, all evidence is physical. The question, always, is about how strong a given piece of evidence is. In the post, I mentioned two rules for this: (i) the closer the spatiotemporal connection, the stronger the evidence -- something which follows from the laws of physics; and (ii) high-prior data is at most weak evidence of a low-prior hypothesis (or: thou shalt not postulate a strange thing to explain a less strange thing) -- an immediate consequence of Bayes' Theorem.

If a person's behavior were sufficiently unusual, it might constitute significant evidence they were involved in a homicide. And if a murder occurs in Knox's house, Knox is clearly one of the first people the police should interview. But the psychological evidence against Knox is in fact very weak: the causal linkage between Knox's cartwheels, phone calls, or speculation about Lumumba's involvement on the one hand, and a hypothetical murder committed by her on the other is very tenuous compared to the causal links between these things and more local factors which are likely to be largely independent of Kercher's murder. And yet, many people mistakenly believe the evidence is strong. Why? Because, for perfectly understandable evolutionary reasons, people are interested in psychology; it's salient in their minds, and they mistake this salience for evidentiary strength. They find it easy to imagine a guilty Amanda Knox doing cartwheels, and caught up in the narrative, forget to properly consider the ways in which an innocent Amanda Knox could also end up doing cartwheels. (In fact cartwheels were never something particularly unusual for Knox.) And, in continuing to consider such weak evidence against Knox after the strongest evidence in the case -- the evidence from Kercher's room -- has pointed decisively to the crime having been committed by Rudy Guede, they compound the error by privileging the hypothesis, or, in other words, overestimating the prior probability, of Knox's guilt.

Replies from: komponisto
comment by komponisto · 2010-01-15T21:05:37.941Z · LW(p) · GW(p)

(3) Object-level arguments from a few people who (still) think there is a significant chance Knox and Sollecito are guilty.

There don't appear to be many LW regulars who assign high probabilities to Knox and Sollecito's guilt. There are a few who remain apprehensive about doubting the rationality of the jury or of people like Judge Micheli (the judge in the Guede case) to the extent of lowering the probability of guilt to single digits of percentage; but mainly, they agree that acquittal is called for. My remarks here will thus be directed mostly at people chancing upon this post from outside.

It is incorrect to assume, as some people have, that because I didn't mention various facts about the case in this post, that I am therefore unacquainted with them. On the contrary. However, I do assert that the essence of the case -- the decisive information -- is just what I presented here. Among my main points was that people have been distracted by various other details to the point of getting the wrong answer. The central case in point would be the eight members of the Perugian jury, who despite hearing all kinds of information over the course of nearly a year, were unable to sort out the clutter from the essential facts, which are these:

  • The prior probability of Knox and Sollecito having committed murder is extremely low; of having committed this particular kind of murder, even lower.

  • Since Guede is unquestionably responsible, the mere fact of Kercher's death does not need to be explained.

  • There is no evidence that Knox was in Kercher's room on the night of the crime, and almost no evidence that Sollecito was.

  • There is almost no evidence of any association between Knox and Guede, still less of any between Sollecito and Guede.

  • There is no evidence of antipathy toward Kercher on the part of Knox or Sollecito, or of any other plausible motive for the crime.

  • Every piece of apparently strong prosecutorial evidence has either been totally discredited or is subject to serious doubt (examples: footprints, "mixed" blood, knife, bra clasp, cleanup,...).

  • The remaining prosecution case consists of odd physical facts that are nowhere near as strange as Knox or Sollecito being guilty (broken window circumstances, apparent rearrangement of scene), dubious psychological inferences (inconsistencies => cover-up, cartwheels => not sad, not sad => guilty), and outright non-sequiturs (Knox named Lumumba & Lumumba innocent => Knox hiding something).

  • Knox and Sollecito (along with Lumumba) were suspects before Guede was; the basic theory of the crime was not revised when Guede was discovered.

The above facts are indisputable; there can be little question about which way the winds of evidence blow in this case. Yes, there are lots more detailed facts you can learn about the case (and I know a bunch of them), but as regards the question of who is guilty and who is not, the above is what you need to know, and the rest is noise.

Replies from: rolf_nelson
comment by rolf_nelson · 2010-02-01T20:41:25.293Z · LW(p) · GW(p)

Point-by-point:

Given that AK's roommate is dead, a break-in was staged, and the coroner's report showed multiple attackers, the prior on AK being a murderer of Meredith is rather high. On the other hand, if we throw away all known evidence, the prior of AK (or Guede, for that matter) being a murderer of Meredith is less than one in a trillion. I claim the former approach, where you use evidence rather than ignore it when it's inconvenient, is preferable. [Edit: OK, that was too snarky. Let me instead say that you should start with a tighter prior rather than a looser prior where possible; it makes the math more tractable.]

That said, I think our main disagreement is on whether the prosecutorial evidence holds up.

  1. Why do you believe DNA evidence flies around so easily? Quick tests: Do you find your beliefs about DNA match up with how DNA is used to draw conclusions in any other court cases that you're familiar with? Why was RS and the other roommate's DNA not found in more areas? Google any video of a DNA testing lab. Are they wearing hazmat suits and, if not, why aren't the testers contaminating their own samples left and right?

  2. I disagree the five pieces of evidence you listed (footprints, DNA-mixed blood, knife, bra clasp, cleanup) are discredited. I am interested in hearing why you personally believe each of them is not strong evidence. [Edit: if you limit yourself to one item, my order of preference is DNA-mixed blood, then knife, then bra clasp.)]

  3. Outside of those five pieces of evidence, I also think you're being too dismissive of the other pieces of evidence. For example, why is Knox naming Lumumba a non-sequitur?

  4. If the basic theory was that multiple people, including at least one roommate, killed MK, then there was no reason to abandon that basic theory upon discovering Guede.

Am I correct in that one of our disagreements is this:

Observation: AK claimed she saw Lumumba kill Meredith. Lumumba was therefore detained by the police based on her affidavit, but Lumumba turned out to be innocent.

Your conclusion: The presence of this false accusation decreases the probability of AK's guilt (?!) (Because it somehow leads credence to a railroading theory? You may be buying into a false FoA meme that the prosecution merely replaced Lumumba with Guede to save face.)

My conclusion: The presence of this false accusation increases the probability of AK's guilt.

Replies from: Jack
comment by Jack · 2010-02-01T23:48:53.213Z · LW(p) · GW(p)

My ADHD brain lost interest in this after the huge discussion here covered pretty much everything having to do with the trial. And komponisto knows this stuff way better than I do so I'll let him respond. But nearly all of the regulars here looked at the exact same evidence you are bringing up now and nearly all of us eventually concluded that it was more likely than not that AK was innocent. Moreover, I specifically recall discussions of every single point you bring up and I believe every single one was resolved. So you might want to look back at the comments to the original post (the test of your rationality one) before you make komponisto go through all this again.

Since I was heavily involved in the discussion of the Lumumba 'accusation' I'll just add this: If AK and RS cleaned up their own involvement with the crime, but intentionally left the evidence implicating Guede wtf would AK not just accuse him to begin with? It seems likely bordering on obvious that AK was interviewed under duress, that the police had seen her text to Lumumba as implicating evidence and fed her his guilt. As a result, AK either made up or dreamed this bizarre pseudo-memory in which Lumumba was present. Then when Lumumba was cleared and an actual suspect was found they kept AK in their hypothesis so as to not totally embarrass themselves. Indeed, this explanation is one of the few parts of the story where I feel like I can account for every single fact and where no other particularly different explanation makes sense. Even if Knox did kill Kercher I would still assign this kind of story a high probability.

comment by captcorajus · 2009-12-17T03:51:44.281Z · LW(p) · GW(p)

komponisto, can I just say that you have very eloquently voiced my very thoughts on this case. In my blog article, "Logic Trumps Innuendo" I wrote the following:

"As I surf the net, reading a variety of comments in regards to this case there is much speculation about evidence in this case. Much of it was not used at trial, but somehow made it into the public consciousness through ongoing press leaks during the investigation, such as:

"Knox was seen with a mop and bucket the morning of the murder." What does that mean exactly? The innuendo would be that she cleaned the crime scene, but see the logic problems posed by that below.

"Knox purchased bleach the morning of the murder, there are receipts." No receipts were presented at trial, but even if there were what how is that probative?

"The found the murder weapon in Sollecito's flat." They found his knife, in his flat, in his drawer. Logic alone makes it unlikely that this is the murder weapon, and the prosecution's own analysis reinforces this. See logic question below as to why.

"Meredith's bra had Sollecito's DNA on it." Left on the floor of Knox's flat for 47 days after the murder, a variety of DNA including Sollecito's was found on the seperated clasp, not the bra itself.

... and on and on. I offer no explanation in this article for these, but simply pose some logic questions that address conflicting and incompatible ideas with the facts. This approach certainly reveals some troubling problems with the case against Knox and Sollecito. The unspoken question at the end of each of these is simply, "If this is so, how is that possible?"

Logic problem 1: They had the temerity to properly dispose of their bloody clothes and shoes, but then took the murder weapon home, cleaned it thoroughly, and put it back in the drawer?

Logic Problem 2: They cleaned the knife so well that luminal had no reaction, no blood was found on the knife, but the low copy skin DNA of the victim somehow remained on the blade???

Logic Problem 3: With a mop and bucket they somehow managed to selectively clean the murder scene clean of their DNA and fingerprints but leave behind Rudy Guede's??

Logic Problem 4: The bra clasp collected 47 days after the murder had Sollecito's DNA on it, but the bra itself did not???

Logic Problem 5: Meredith Kercher's bedroom door was locked from the inside and had to be broken down to gain entry. How did Knox get in there and remove all of her and Sollecito's fingerprints and DNA and leave behind Rudy Guede's?"

I too have felt this case begs for the the application of Occam's Razor. You simply can't connect Knox and Sollecito to Guede, much less put them into some three way sexual tryst. My logic circuits implode at the prosecutor's inane theory, which to prove you would need significantly more evidence than what was presented at trial.

Replies from: brazil84
comment by brazil84 · 2009-12-17T15:47:47.136Z · LW(p) · GW(p)

It seems to me that most of those problems can be explained by postulating that (1) the prosecution's case is overstated; and (2) the prosecution's scenario of what happened is incorrect.

However, even if (1) and (2) are true, it does not mean that Knox and Sollecito are innocent or uninvolved in the murder.

By analogy, consider the OJ Simpson case. As I recall, there really were some serious questions about the prosecution's evidence in that case. Even so, it seems pretty clear (to me) that OJ was guilty.

Obviously the OJ Simpson case is very different from the Amanda Knox case. But the point is that police, prosecutors, and others are often tempted to try to turn a good case into a great case.

Of course one big difference with OJ Simpson is that the case fits into a very simple paradigm: the jealous ex-husband. So it's very easy for the prosecution to present a coherent theory (including a motive).

Perhaps a better analogy is the Annie Le case. It seems pretty clear who killed her, but it's not entirely clear why. Nevertheless, there will be pressure on the prosecutors to come up with a scenario for what happened and why.

Replies from: captcorajus
comment by captcorajus · 2009-12-18T04:42:16.080Z · LW(p) · GW(p)

There is a lot of what I call "noise" in this case. Things that MAY apply, but not all of them carry the same weight, thus it becomes necessary to organize my thought processes. I start with the hard evidence FIRST, not the other way around. I do not look at the people and then find evidence to implicate them, I look at the evidence first and then find the people.

By "hard evidence", I mean that evidence that can be observed directly or by repeatable scientific methods.

I refine my thought process even further by using these principles which state: 1. The simplest explanation that fits the facts is usually the correct one. 2. the more outlandish a theory is the greater the amount of evidence is required to support it, and 3. The further away you move from a causal event the less accurate your observations will be.

With that as a guide, the DNA of Rudy Guede inside Kercher becomes a white hot beam of guilt, and Knox's cartwheels with the police has almost no luminescence at all.

Given how much evidence is in the room where Kercher was killed leads you directly to Rudy Guede. The bedroom is the key to this case as that is where the murder took place. As you move further away from the bedroom, you are less likely to find direct connection to the killer or killers, so as I move out of the bedroom other things like mixed DNA in a bathroom of people who co-habituate get less consideration.

Given the preponderance of evidence that there is of Guede, logically then, this must also be true for Knox and Sollecito if the prosecution's theory of the crime is to hold true. However, no such preponderance of evidence exists for them. Knox's presence is non existent according the the physical evidence, and Sollecito's hinges on a bra clasp found 47 days after the crime. The more outlandish a theory is the greater the amount of evidence is required to support it, ergo which version of the crime does the evidence and logic support:

That a known burglar, involved in three separate break-in incidents in the weeks prior to the murder broke in and robbed, assaulted and murdered Kercher.

Or

That new lovers Knox and Sollecito with no criminal history whatsoever, conspired with relative unknown Guede to involve Kercher in some sex game and inadvertently killed her?

This leaves Knox, Sollecito and Lumumba footnotes in this story. Stories about bleach purchases, hip wiggling, knives in a residence not connected to the scene, Myspace pages, emials and raunchy tabloid stories about an attractive American female and her Italian boyfriend are relatively benign compared to fingerprints in blood, feces in the toilet and DNA inside the victim.

Using THIS method, which is the traditional method of deduction leads you to the guilty party. Using disassociated bits of information that you then try to connect to hard evidence found latter only leads to confusion. Bragging about it only leads to a need for obfuscation when the hard evidence contradicts your theory.

Replies from: brazil84
comment by brazil84 · 2009-12-18T12:12:45.274Z · LW(p) · GW(p)

"That a known burglar, involved in three separate break-in incidents in the weeks prior to the murder broke in and robbed, assaulted and murdered Kercher.

Or

That new lovers Knox and Sollecito with no criminal history whatsoever, conspired with relative unknown Guede to involve Kercher in some sex game and inadvertently killed her?"

Are those the only two possibilities? As an attorney, I can tell you I have seen many many cases where neither side's theory about events is very credible.

It seems pretty clear to me that the answer to my question is "no," but I would like to hear your take.

Replies from: wedrifid
comment by wedrifid · 2009-12-18T12:28:23.524Z · LW(p) · GW(p)

As an attorney, I can tell you I have seen many many cases where neither side's theory about events is very credible.

As an attorney you are asking a tangential question with the implication that it has more relevance than it does.

Replies from: brazil84
comment by brazil84 · 2009-12-18T12:45:20.046Z · LW(p) · GW(p)

I remember when I started practicing law on my own I would be outraged when I caught the other side in numerous lies and yet the judge would still go against my client. At the time, it seemed to me that the judge was heavily biased against my client.

It took me a while to learn what I have tried to share in my last couple posts. In hindsight, I realize that most of those clients really did do pretty much what they had been accused of doing. And that in any event, the judge was (generally speaking) making a reasonable assesment as to my client's guilt or innocense.

The fact that the prosecution's case has holes in it doesn't necessarily mean that the Defendants were innocent or uninvolved in the murder.

But feel free to explain why you think my question is tangential or irrelevant and I will be happy to consider it.

Also, you might ask yourself if you are angry at me over our previous exchange and whether this anger is coloring your judgment.

Replies from: wedrifid
comment by wedrifid · 2009-12-18T13:51:29.776Z · LW(p) · GW(p)

But feel free to explain why you think my question is tangential or irrelevant and I will be happy to consider it.

I will wait and see if anyone else finds my objection to your rhetoric hard to understand.

Replies from: brazil84
comment by brazil84 · 2009-12-18T18:30:56.461Z · LW(p) · GW(p)

Suit yourself. In essence, I am pointing out that there are other possibilities besides the 2 scenarios described by captcorajus.

If you feel that my observation is so obviously tangential or irrelevant that no explanation is required beyond simply stating that it is tangential or irrelevant, then so be it. People can draw whatever inference they wish. My inference is that you have no good explanation for your claim, but of course I am starting from the belief that my observation was relevant. (Otherwise I would not have made it.) If someone else sees things differently, perhaps they can shed some light on the issue.

Replies from: radical_negative_one, wedrifid
comment by radical_negative_one · 2009-12-18T19:25:00.735Z · LW(p) · GW(p)

So, you're suggesting that Knox and Sollecito are guilty, but for reasons other than the prosecution's argument. The other commenters here have been discussing the issue, so maybe if you have other arguments, or can point us to another source, that would be relevant.

If you're just saying, "But captcorajus might be wrong," that doesn't strike me as being terribly useful, without any further insight to explain why.

I realize that most of those clients really did do pretty much what they had been accused of doing.

Or, are you saying the fact that Knox and Sollecito were in a courtroom as defendants is enough to conclude that they're guilty?

Replies from: brazil84
comment by brazil84 · 2009-12-18T20:05:38.675Z · LW(p) · GW(p)

"So, you're suggesting that Knox and Sollecito are guilty, but for reasons other than the prosecution's argument."

Not exactly. I'm saying that there is good reason to be skeptical of the prosecution's scenario. Nevertheless, the evidence is sufficient to be reasonably confident that Knox and Sollecito were involved in the murder.

"If you're just saying, 'But captcorajus might be wrong,' that doesn't strike me as being terribly useful, without any further insight to explain why."

I'm saying, in essence, that captocorajus' argument rests on a false dilemma. Implicitly he is asking us to choose between 2 possibilities when in reality there are other possibilities.

"Or, are you saying the fact that Knox and Sollecito were in a courtroom as defendants is enough to conclude that they're guilty?"

No, I'm not saying that. I'm saying that holes in the prosecution's case do not necessarily imply innocence on the part of the defendants. (As a practical matter, without knowing more, the fact that somebody is a defendant is indeed good evidence they are guilty. But here we do know more so I have not been relying on the mere fact of prosecution.)

Replies from: captcorajus
comment by captcorajus · 2009-12-18T23:02:24.889Z · LW(p) · GW(p)

Might I interject here boys. My two options for the scenario were based on what the tangible evidence in the case indicates. There is certainly a 3rd possibly that people other than Sollecito and Knox are involved, BUT no evidence has been presented to indicate this so I didn't mention it.

Rudy Guede's involvement is about as certain as one can get without direct observation. His bloody handprind, his feces in the toilet and his DNA inside the victim All tangible, all verifiable by second parties.

No such tangible evidence exists for Sollecito or Knox. If they were there something of their presence MUST be there.

Innuendo, and behavioral analysis without corroborative evidence is not evidence of murder. Rudy Guede can't even be connected to Sollecito and Knox. No emails, no phone calls.... nothing. Rudy Guede is connected to the flat though through downstairs male roommates who testified at his trial that during one visit he fell asleep on their toilet.

This case, and the fever that surrounded in regards to Knox borders on misogyny. For Knox, the only bright side is they no longer burn witches in Italy.

Replies from: brazil84
comment by brazil84 · 2009-12-19T00:23:18.118Z · LW(p) · GW(p)

"Might I interject here boys. My two options for the scenario were based on what the tangible evidence in the case indicates. There is certainly a 3rd possibly that people other than Sollecito and Knox are involved, BUT no evidence has been presented to indicate this so I didn't mention it."

There are many other possibilities (besides your two scenarios) which are consistent with the evidence and consistent with Knox and Sollecito having been involved in the murder.

"Innuendo, and behavioral analysis without corroborative evidence is not evidence of murder."

Are you saying there is no circumstantial evidence which suggests involvement of Knox and Sollecito?

Replies from: komponisto, wedrifid
comment by komponisto · 2009-12-19T01:24:47.946Z · LW(p) · GW(p)

Are you saying there is no circumstantial evidence which suggests involvement of Knox and Sollecito?

No. The claim is that this evidence is weaker than the evidence against Guede by a factor of millions, and therefore deserves essentially zero brain time. See the "Epistemic Ruthlessness" section of the post, and the wiki entry "Amount of Evidence".

Replies from: Eliezer_Yudkowsky, brazil84
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-19T02:51:01.930Z · LW(p) · GW(p)

The claim is that this evidence is weaker than the evidence against Guede by a factor of millions, and therefore deserves essentially zero brain time.

No, the evidence is weaker than it would need to be to overcome the prior improbability of "a rape known to have been committed by a random burglar in a flat was a product of conspiracy with a woman who lived there", plus the absence of Knox DNA is very strong evidence against her presence. The degree of the evidence against Guede has nothing to do with the bar - the bar is set by the prior improbability, not by the strength of evidence that Guede happened to leave behind himself.

comment by brazil84 · 2009-12-19T01:53:53.685Z · LW(p) · GW(p)

The claim is that this evidence is weaker than the evidence against Guede by a >factor of millions and therefore deserves essentially zero brain time.

It seems to me that (1) Guede murdered Kircher; and (2) Knox and Sollecito were involved in the murder, are not mutually exclusive hypotheses.

So the fact that there is an extremely strong case against Guede does not necessarily mean that the case against Knox and Sollecito is weak or extremely weak.

Replies from: komponisto
comment by komponisto · 2009-12-19T02:01:35.293Z · LW(p) · GW(p)

So the fact that there is an extremely strong case against Guede does not necessarily mean that the case against Knox and Sollecito is weak or extremely weak.

Indeed not; if we had 30 bits of anti-Knox evidence, the case against Knox would be strong too.

The case against Knox and Sollecito is weak because it is weak, not because the case against Guede is strong.

Replies from: Eliezer_Yudkowsky, brazil84, erica
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-19T02:47:30.954Z · LW(p) · GW(p)

The case against Knox and Sollecito is weak because it is weak, not because the case against Guede is strong.

That's why I keep on saying not to compare the amount of evidence against Guede to the case against Knox. It's not a comparison operation. It doesn't set a bar. It doesn't set a standard. Now, the fact that Guede left a lot of DNA means it's implausible that Knox cleaned up only her DNA and not Guede's, but that's a whole separate issue. And the fact that we know Guede did it means that there's no unexplained murder around for Knox to be convicted of. But under other circumstances, it would be very easy to have a murder that was in fact committed by two people, one of whom left very strong evidence against herself, and one of whom left less strong but still conviction-worthy evidence against herself. It's just not a relative operation.

Replies from: komponisto
comment by komponisto · 2009-12-19T03:26:17.517Z · LW(p) · GW(p)

Okay, I agree that ideal rational agents with unlimited computing resources shouldn't "care" about the relative strength of evidence; all they have to do is perform the appropriate computation, and the result will come out to whatever it should be. But I've already conceded that "follow the strong signal" is a heuristic for human use, in order to get results that, in reality, better approximate what an ideal rational agent would come up with than the methods that are already programmed into us.

The situation we're in is the following: we're investigators on a budget, trying to figure out how to allocate our limited resources among various paths through hypothesis space. Let's say there are two particular paths we're considering, and at the entrance to each of them is a loudspeaker with a voice saying "FOLLOW THIS TRAIL". Except that one of the voices is twice as loud as the other. Now, am I completely crazy, or is it not an epistemically reasonable thing to do to do something like allocate twice the investigative resources to following the signal that is twice as strong? How else should we divide it up?

I don't think I need to remind you that reality is consistent: if Knox was really involved in a conspiracy with Guede, then the Knox trail will meet up with the Guede trail, in which case we're not losing anything by devoting the lion's share of our resources to starting along the Guede trail rather than the Knox trail.

What, if anything, am I missing here?

Replies from: Eliezer_Yudkowsky
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-19T04:46:32.046Z · LW(p) · GW(p)

The problem is that finding Guede's semen inside Meredith is not evidence against the hypothesis "Guede and Knox murdered Meredith". Guede's already been caught, too. So now the question is whether to devote any of our remaining attention to trying to catch Knox, and the insufficient/disconfirmatory evidence for this fails to surpass the prior implausibility of the conspiracy hypothesis - it has nothing to do with how hard Guede was caught.

Replies from: erica
comment by erica · 2009-12-19T10:11:24.360Z · LW(p) · GW(p)

Are you sure semen was found? I've read elsewhere this was a manual rape - still leaves DNA inside but not necc. semen.

Replies from: Eliezer_Yudkowsky, wedrifid
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-19T18:06:16.815Z · LW(p) · GW(p)

Nope, not sure offhand.

comment by wedrifid · 2009-12-19T10:30:36.497Z · LW(p) · GW(p)

I've read elsewhere this was a manual rape - still leaves DNA inside but not necc. semen.

Manual rape? I'm not familiar with that term and a meaning fitting those criteria (DNA but not semen) isn't obvious. I can only assume that 'manual' refers to, well, the last part of it. I wouldn't have expected that kind of rape if murder was going to be on the cards and I would also expect semen around somewhere, showing up with luminol. So perhaps something else is meant.

Replies from: anonym
comment by anonym · 2009-12-19T21:18:11.630Z · LW(p) · GW(p)

One meaning of 'manual' is 'of or relating to the hands'. I'm guessing that's what's meant here.

comment by brazil84 · 2009-12-19T02:15:58.410Z · LW(p) · GW(p)

I agree with this, except of course that I am reasonably confident Knox and Sollecito were involved in the murder.

Replies from: komponisto
comment by komponisto · 2009-12-19T02:17:58.841Z · LW(p) · GW(p)

And that would be because...?

(The fundamental question of rationality: why do you believe what you believe?)

Replies from: brazil84
comment by brazil84 · 2009-12-19T02:40:10.645Z · LW(p) · GW(p)

Mainly because (1) there is evidence of alteration/staging; and (2) Knox and Sollecito are still unable to give accounts of the evening (and next morning) which are reasonably coherent and consistent.

Replies from: komponisto, erica
comment by komponisto · 2009-12-19T02:44:00.606Z · LW(p) · GW(p)

How many total bits of evidence against Knox and Sollecito do you think these things are worth?

Replies from: brazil84
comment by brazil84 · 2009-12-19T02:48:00.728Z · LW(p) · GW(p)

I'm not sure . . . I'm ignorant of the evaluation of evidence in terms of "bits." Is there some link you can give me?

Replies from: Vladimir_Nesov, komponisto
comment by komponisto · 2009-12-19T02:50:46.565Z · LW(p) · GW(p)

Yes.

Replies from: brazil84
comment by brazil84 · 2009-12-19T02:54:20.733Z · LW(p) · GW(p)

If my math is correct, I would say somewhere between 3 and 4 bits.

comment by erica · 2009-12-19T10:24:19.452Z · LW(p) · GW(p)

I just want to say thanks for your posts, I have found them very interesting.

If the trial has been corrupted then one has to ask why the judge(s) involved would collude in such high profile corruption - that in itself seems unlikely unless there is an unsopken intention to reverse the verdict at appeal, having given the US 'a dose of it's own'. But that seems far fetched. Corruption happens for a reason and those reasons are also traceable.

Your argument that conviction was secured on the basis of a fanciful explanation but not without reason is persuasive. I too am of the opinion that things went on but I'm not sure that makes A and R as evil as they are portrayed or even guitly of murder.

But mainly, your posts are valuable because, without being able to argue the case mathematically, something clearly is wrong with this Bayesian worldview because it is not explaining life, and if Bayesian rationality is the key to 'knowing', as we are led to believe, then I would not be left feeling that many posts that adhere strictly to Bayesian reasoning are somehow missing the point. And I don't think that is because I am an evolutionary throw-back, I think it is because I have a good sense of things not sounding right - I have that feeling with the Knox trial and with this blog. Ciao

comment by erica · 2009-12-19T02:30:53.821Z · LW(p) · GW(p)

or it could be that Knox and Sollicitos' behaviours were so irrational that it is harder to fathom what the evidence means:

  1. they both retracted statements
  2. Italy's legal system has been praised as well as criticised
  3. the footprint on the bath mat paradox
  4. the picture on S's blog
  5. K's rape story
  6. the verdict is for 'involvement' not physical action
  7. capacity to be irrational induced by drugs, hormones, a generational obssession with the supernatural, and the perennial boredom of the over-educated bourgeoisie

I reckon that whatever happened that night, K/S got so close to the boundary between fanatsy and reality that they couldn't risk admitting whatever folly they had been up to.

I think what is on trial is culture. I count at least 8.

comment by wedrifid · 2009-12-19T00:30:34.635Z · LW(p) · GW(p)

Use ">" at the start of a line to quote.

It is more readable.

Replies from: brazil84
comment by brazil84 · 2009-12-19T00:51:02.665Z · LW(p) · GW(p)

Use ">" at the start of a line to quote.

Thanks for the tip.

comment by wedrifid · 2009-12-18T23:45:44.233Z · LW(p) · GW(p)

Please see the response from RNO (for a start).

People can draw whatever inference they wish. My inference is that you have no good explanation for your claim,

One inference that people may draw is that I am familiar with this kind of game and choose not to play.

Replies from: brazil84
comment by brazil84 · 2009-12-19T00:28:04.691Z · LW(p) · GW(p)

"Please see the response from RNO (for a start)."

I don't see anything in RNO's response which would offer an explanation for your claim. On the contrary, it appears that RNO simply misunderstood my point and I explained myself a bit further.

Replies from: radical_negative_one
comment by radical_negative_one · 2009-12-19T02:03:47.857Z · LW(p) · GW(p)

Ah, i think i see the problem here.

You say that a weak prosecution does not equal an innocent defendant. I think we can all agree on that.

You say that there are other explanations for the evidence. Sounds reasonable enough; after all, even if we're sure of something, we're not absolutely sure, not 100% sure.

Back in the first "you be the jury" thread, there was a general agreement that Guede was guilty and Knox was innocent. For Knox, as i recall, there were various estimates from 10% to 30% chance of guilt, thus a judgment of "probably innocent / not likely enough to convict". So, i think it's not that nobody is considering any other explanation, rather, they're convinced that this one explanation is correct.

Saying, "there might be another explanation" is a good idea as a general point, but that doesn't mean that another explanation is particularly likely. You keep saying "there are other possibilities" but the problem is: what other scenario are you suggesting, and why should we believe it?

Replies from: brazil84
comment by brazil84 · 2009-12-19T02:35:32.729Z · LW(p) · GW(p)

You keep saying "there are other possibilities" but the problem is: what other >scenario are you suggesting, and why should we believe it?

I'm not suggesting any particular scenario. There simply isn't enough evidence to make a good guess at what happened in the hour or two leading up to Kircher's death.

It's a bit like the Annie Le case in New Haven. It's reasonably clear who the killer was, but it's not clear why he did it.

In any murder case, there is a lot of pressure on the prosecutor to put together a scenario as to how and why the killing happened. And usually it's not too hard to do. i.e. to paint the defendant as a jealous ex-husband; a robber; a competing drug dealer; etc.

But I'm not the prosecutor so there's no need for me to put together any scenario. I'm reasonably confident that Knox and Sollecito were involved in the murder, but I do not know what their role was or why they did it.

comment by Sebastian_Hagen · 2009-12-13T18:41:46.142Z · LW(p) · GW(p)

Excellent post. I don't think I'm ready to wield those sharp implements with quite so much flourish yet; the chance of lopping off my own limbs is currently too high.

However, there are some specific parts of your post I disagree with.

You have to shut that voice out. Ruthlessly. Because it has no way of knowing. That voice is designed to assess the motivations of members of an ancestral hunter-gather band. At best, it may have the ability to distinguish the correct murderer from between 2 and 100 possibilities -- 6 or 7 bits of inferential power on the absolute best of days. That may have worked in hunter-gatherer times, before more-closely-causally-linked physical evidence could hope to be evaluated. (Or maybe not -- but at least it got the genes passed on.)

Agree completely. Now apply it both ways. Specifically:

But the prior probabilities of such scenarios are low, even in general -- to say nothing of the case of Knox and Sollecito specifically, who, tabloid press to the contrary, are known to have had utterly benign dispositions prior to these events, and no reason to want Meredith Kercher dead.

This is extremely weak evidence. If you think that psychology doesn't really matter (and I agree with that), then it notmatters in both directions. There's no obvious motive, but that's very weak evidence that no motive existed. We just don't have enough evidence for what these people really think like, relative to the population at large. Re. motive, I'd definitely stick with the prior for murderous intentions among associates.

nor, while we're at it, do the 100 picograms (about one human cell's worth) of DNA from Meredith allegedly on the tip of a knife handled by Knox, found at Sollecito's apartment after the two were already suspects [count]

I was surprised at you dismissing the knife DNA evidence. The linked FOA page claims:

Low Copy Number (LCN) tests, like the one performed on the knife blade, are regarded by many experts as inherently unreliable, because it is not possible to prevent biological contamination at the level of picograms. Even in well-run labs, control samples regularly show up with DNA that theoretically should not be there.

The actual experts doing DNA-testing in the case evidently thought that it was significant evidence. Wikipedia has an article on LCN, though a lot of the citations are broken. According to the article, the method went through an extensive review, and was finally cleared for use in the UK justice system (and with a fairly definite statement at that: "The CPS has not seen anything to suggest that any current problems exist with LCN"). The situation in some other western countries appears to be rather different, though. I still think this is fairly strong evidence, though much less so than I did before doing some research on the general acceptance of this test method.

While not particularly flattering to the defendants (how would you like to be told that there's a 35% chance you're a murderer?)

Keep in mind this verdict uses (among other pieces of information) the existing jury verdict as empirical evidence (and of course in our epistemological position, that's the right thing to do); if our judgements had been based on just the primary evidence - i.e. without an existing guilty verdict by a jury - these probabilities would have been lower.

Replies from: Questor, McJustice
comment by Questor · 2009-12-16T02:07:44.211Z · LW(p) · GW(p)

Low copy number Test... you left out that there are very few labs certified as being acceptable to do that test which is still regarded as experimental and in the UK there is a stringent set of minimum standards for equipment, procedures for the lab itself not to mention the person doing the test. Would you be surprised to hear that the lab that did the test did not meet these requirements in the slightest? It may also be true that though equipped for standard DNA tests was not technically certified at the time even for that? An expert who is convinced the results are reliable when she had never done this type of test before using equipment not designed or set up for such extreme amplification plus leaving out the other calibration tests and tests on a control and not releasing a lot of other details of what she did. She is an employee of the Italian Government just like the prosecutor who unlike many other systems also runs or in this case directs the investigation. The results on the Bra clip and the knife blade are not scientifically usable and should never have been accepted as reliable evidence. This is in the realm of pseudo science. these links have all the details http://freeaman.001webs.com/pdfs/LCN_DNA_I.pdf http://freeaman.001webs.com/pdfs/Methods_of_the_Polizia_PseudoScientifica.pdf The same with pictures and video http://www.sciencespheres.com/2009_10_01_archive.html And New Scientist Magazine has an article about concerns that world experts in DNA testing have. http://www.sciencespheres.com/2009_10_01_archive.html http://freeaman.001webs.com/pdfs/LCN_DNA_II.pdf All of this leaves 2 key bits of evidence, the only 2 alleged to link AK or RS to the crime scene... revealed to not be credible evidence at all no matter what the prosecution expert(s) said about it

This blog is great... the lead post does a good job of showing that the theory came first before any evidence and all the efforts since then have been aimed at proving the originally baseless theory which was based on pop psychology disguised as some sort of science...Dietrologia combined with a casual hunch driven version of BIA Behavioral Interview analysis. http://deception.crimepsychblog.com/?p=78 And just this short clip of Giobbi, the lead investigator at the start... is just about the best encapsulation of the mindset that originated and drove the entire wrongheaded prosecution. THEORY First , evidence after... http://www.youtube.com/watch?v=sWkZPWRS3N0&feature=PlayList&p=A24DFCC06CD8360D&index=0

Replies from: Sebastian_Hagen
comment by Sebastian_Hagen · 2009-12-16T14:23:03.520Z · LW(p) · GW(p)

Very interesting reports about the LCN analysis performed in this investigation; I hadn't come across those before (FOA doesn't seem to link to them). This diminishes my confidence in those results meaning much of anything significantly. Thanks!

Replies from: pataz1
comment by pataz1 · 2009-12-16T23:46:32.455Z · LW(p) · GW(p)

The problem for the trial was the Defense's argument against the DNA on the knife was undermined by Sollecito admitting there may be the victim's blood/dna on the knife because of a dinner at his house that never happened. Although it tested negative for blood, at that point, the critique against the LCN DNA on the knife is almost superfluous. Sollecito made up a reason to excuse evidence that the defense was challenging the proof of.

comment by McJustice · 2010-01-02T23:20:05.074Z · LW(p) · GW(p)

About LCN DNA... only the UK currently approves that kind of evidence in a trial BUT they have an extremely strict set of standards on how to run those kinds of tests AND require a very expensive specially built and equipped lab. There are very few DNA labs in the entire world that comply. And there are not many properly trained "experts" who are certified to carry it out. I should mention that none of those labs happen to be in Italy and the Italian technician was not trained or certified to do it. Also her boss in the lab worked as a paid consultant for Mignini at times and there is the implication that she was under the gun to come up with results.

All her original DNA tests showed no DNA on the knife at all. Only when she circumvented the built-in limits in the equipment and without doing any of the recommended calibration for false positives and running a lot more amplification runs did she finally come up with partial matches in a very statistically noisy result. And even then great care must be taken in interpreting the results which are much more liable to contamination than standard DNA tests. And even at this point the results with her "interpretation" of the results only yields suggestion of Meredith's DNA... not blood. And this is important: If the knife was cleaned with bleach there would be no DNA but blood would still be detectable. And blood was not detected. The test for blood is very sensitive and it is very hard to eliminate all blood traces and yet there was no blood. That implies strongly that whatever DNA was detected was contamination and a weak result open to interpretation. Her DNA test reports as presented to the court are not complete so the entire process she used for all of these key tests is not available for review. Additionally the court did not allow defense DNA experts to testify about the faults in the prosecution's DNA evidence.

Italian judges have poor understanding of forensics and tend to accept unquestioningly the results of government forensic labs.

http://www.foreignpolicy.com/articles/2009/12/10/can_anyone_get_a_fair_trial_in_italy "For one, they say that coerced confessions and the use of dubious forensic evidence, as might have happened in the Knox case, are way too common. "Inquiries are conducted without any reliable methods," says Roberto Malini, president of EveryOne, a nongovernmental organization that defends ethnic minorities in jail. "Tests take place solely in the laboratories of the state police. There's no independent lab, and independent observers do not have access to the police's work."

"Legal experts also share concerns about Italy's bar for admissibility. Il Giornale, a conservative newspaper, for instance, recently published an interview with Marco Morin, a Venice-based firearms expert who declared he no longer wanted to work in Italian courts. "In the United States, federal judges must study a 637-page manual in order to be able to evaluate [forensic] evidence," he told the newspaper. "Here, they accept everything without questioning, as long as it comes from the institutional laboratory."

comment by Jack · 2009-12-13T13:05:17.456Z · LW(p) · GW(p)

Can anyone find statistics that could tell us what is the probability the crime scene at any given murder contains physical evidence sufficient to indicate a suspect? I would expect it to be around .8-.9 but I don't really have any idea. I'm not convinced that that probability is high enough to completely outweigh the probability that AK and RS had something to do with the crime given that

  • they knew the victim

  • are sociable 21 and 24-year-olds (one of them studying abroad) without alibis on a Saturday night

  • the probability that Guede did not act alone (which is high or low depending on how well his presence explains all the evidence at the crime scene with a prior involving the chances any given murder involves more than one perpetrator) Obviously the absence of other physical evidence is evidence that he acted alone, so this value is the probability dictated by the other evidence, rearranged crime scene, broken windows etc.

  • the facts about the morning of November 2, the non-negligible probability RS called the police after the police had arrived, the short phone calls, even the weird behavior that can be explained, which once conjoined, looks like it is at least slightly indicative of being involved in Kercher's murder.

I don't think this is actually sufficient evidence to bring the probability AK and RS are guilty over .5. But it also isn't obvious to me that this evidence is "swamped" by the lack of physical evidence implicating them.

Replies from: Questor
comment by Questor · 2009-12-16T02:29:14.929Z · LW(p) · GW(p)

The phone timing is widely touted as some sort of proof. The postal police actually cannot establish the exact timing that is claimed. there is apparently surveillance camera footage with a time stamp that shows them still en route by car at the time RS made the call. The discrepancy is no more than a few minutes but if this is true it shows either uncertainty or something closer to tweaking facts to discredit RS. I am looking for where I originally saw this as it is actually very important to impeach the police version.

And prior to the call to the regular police RS made a call to his sister-in-law who is a policewoman. And the postal police as far as I know did not mention RS making a call after they came... or if they did it conflicts with the video of them driving there.

Replies from: Jack
comment by Jack · 2009-12-16T05:04:38.185Z · LW(p) · GW(p)

Thus "non-negligible probability".

comment by wedrifid · 2009-12-13T05:26:48.234Z · LW(p) · GW(p)

How did Less Wrong do by comparison? The average estimated probability of Amanda Knox's guilt was 0.35 (thanks to Yvain for doing the calculation).

Yvain! How could you? What did the probabilities do to deserve that kind of abuse? (I strongly assert that averaging the probabilities is not a good way to combine such estimates.)

Replies from: Yvain, ciphergoth, None
comment by Scott Alexander (Yvain) · 2009-12-13T15:01:12.424Z · LW(p) · GW(p)

...and why do you assert that? If you have good reasons, I'd like to see a top level post on the subject, since this is my natural response to a bunch of probability estimates given by different people with the same information who are rational enough that I care what they think.

Replies from: badger, wedrifid
comment by badger · 2009-12-13T17:51:55.040Z · LW(p) · GW(p)

Not a top level post because I don't think I have the definitive say on the matter, but I made an article in the wiki that illustrates why the mean of the log-odds makes more sense.

Unfortunately, the wiki appears to have issues with math right now, so the article has an ugly error message in it. The formula works fine in the Wikipedia sandbox. If anyone knows what is going on or has any other changes, feel free to edit.

comment by wedrifid · 2009-12-13T21:52:02.864Z · LW(p) · GW(p)

...and why do you assert that?

Somebody with no information does not so effectively counterbalance ten people who can describe the positions of every atom on the planet.

I calculated an example involving 0.99, 0.5, 0.745 and (1-10^20) but then I noticed badger's link beat me to it.

comment by Paul Crowley (ciphergoth) · 2009-12-13T09:09:55.747Z · LW(p) · GW(p)

What would the right thing look like? Averaging the log-odds ratio?

Replies from: dilaudid
comment by dilaudid · 2009-12-13T17:33:23.341Z · LW(p) · GW(p)

That's what I would do. If one person is almost certain (say 1/(10^10^10)) then the strength of their view would be represented. Of course if anyone gives an irrationally low or high answer, or puts <=0 or >=1, then it overweights their views/blows up.

comment by [deleted] · 2009-12-13T06:27:28.517Z · LW(p) · GW(p)

I wonder what implications this has for the method of choosing priors I came up with that is "ask everybody in the world what they think the priors should be, normalize the invalid ones, and take the average of all of them".

comment by wedrifid · 2009-12-13T05:04:03.724Z · LW(p) · GW(p)

Am I really suggesting that the estimates of eight jurors -- among whom two professional judges -- who heard the case for a year, along with something like 60% of the Italian public and probably half the Internet (and a significantly larger fraction of the non-American Internet), could be off by a minimum of three orders of magnitude (probably significantly more)? That most other people (including most commenters on my last post) are off by no fewer than two?

Your assertion of such a high probability of guilt does not constitute a claim that most other commenters on your last post were off by no fewer than two orders of magnitude. Probability is subjectively objective. There is one correct estimate for you to have given what you know but this is not the same one that others should have. In fact, given that on average the commenters care less about the subject so did less research if they arrived at the same confidence as you then one of you would probably have to be wrong.

The commenters whose estimates were closest to mine -- and, therefore, to the correct answer, in my view -- were Daniel Burfoot and jenmarie. Congratulations to them. (But even they were off by a factor of at least ten!)

The task isn't to guess your password. The task is to assign probability estimates about the state of their timeline of universe. Their universe does not include the state 'it is probable that Amanda is innocent'.

ETA: I totally agree with your main contentions and found your post both insightful and extremely well written. It is rare to see such well reasoned essays from people who are emotionally entangled with the topic.

Replies from: komponisto
comment by komponisto · 2009-12-13T05:29:42.208Z · LW(p) · GW(p)

Serious nitpicking going on here. The whole point of my post is that from the information provided, one should arrive at probabilities close to what I said.

I don't have appreciably more info than many who participated in my survey, and certainly not more than the jury in Perugia.

Replies from: wedrifid, jpet, aausch
comment by wedrifid · 2009-12-13T06:20:10.328Z · LW(p) · GW(p)

Serious nitpicking going on here.

Probability theories and the philosophies thereof are of interest to me and there are a lot of intuitive traps that are easy to fall into.

The whole point of my post is that from the information provided, one should arrive at probabilities close to what I said.

If that is what your point was then I actually disagree with it. I am not comfortable giving odds of 1:999 after looking briefly at two biassed webpages and a wikipedia page that you tell me is fluctuating at the whims of editorial bias. I know damn well I'd be wrong more than once if I did something like that 1,000 times.

Don't forget that "the order, manner, and quantity of browsing will be left up to [them]". It would be quite reasonable for someone to decide to read until a certain level of confidence has been reached. Once you are 99% confident that the poor girl is innocent what do you hope to achieve by marinating yourself in more and more evidence (or, for that matter, the lack of it)?

It would be great if I could go all Liam Neeson and say "if you let her go now, that'll be the end of it. I will not look for you, I will not pursue you. But if you don't, I will look for you, I will find you, and I will kill you." Alas, I do not have any way to efficiently influence the justice system of Victoria or Australia, much less Italy.

(Damn I hate juries. The thought of being at the mercy of a mob of my peers fills me with equal parts fear and outrage. But it isn't my fight. Except in as much as the only path to a justice system I actually trust probably involves FAI.)

Replies from: Morendil, komponisto
comment by Morendil · 2009-12-13T09:39:40.893Z · LW(p) · GW(p)

How about a Truth Machine ?

Replies from: Blueberry
comment by Blueberry · 2009-12-13T18:54:21.321Z · LW(p) · GW(p)

Wow. That book is really good. Thanks for linking to it!

Replies from: Morendil
comment by Morendil · 2009-12-13T19:02:49.692Z · LW(p) · GW(p)

You might also like The First Immortal by the same author.

comment by komponisto · 2009-12-13T06:35:18.288Z · LW(p) · GW(p)

If that is what your point was then I actually disagree with it. I am not comfortable giving odds of 1:999 after looking briefly at two biassed webpages and a wikipedia page that you tell me is fluctuating at the whims of editorial bias. I know damn well I'd be wrong more than once if I did something like that 1,000 times

What if I tried putting it this way: people underestimate the (potential) power of applying rationality techniques as compared with gathering more raw information. It is sometimes possible to be extremely confident about a proposition after an hour of Internet research, even when people who have spent a year "gathering evidence" seem to disagree shaprly.

Replies from: wedrifid
comment by wedrifid · 2009-12-13T06:51:01.673Z · LW(p) · GW(p)

What if I tried putting it this way: people underestimate the (potential) power of applying rationality techniques as compared with gathering more raw information. It is sometimes possible to be extremely confident about a proposition after an hour of Internet research, even when people who have spent a year "gathering evidence" seem to disagree sharply.

Totally agree, and that's a point that you explained convincingly in your post. Just so long as I don't have to quantise 'extremely confident' as 0.999. Although given an hour and also given that the lesswrong.com discussion is now part of 'the Internet', I expect I would break the 0.99 mark at least.

comment by jpet · 2009-12-14T08:05:02.450Z · LW(p) · GW(p)

Serious nitpicking going on here. The whole point of my post is that from the information provided, one should arrive at probabilities close to what I said.

It's not "nitpicking" to calibrate your probabilities correctly. If someone was to answer innocent with probability 0.999, they should be wrong about one time in a thousand.

So what evidence was available to achieve such confidence? No DNA, no bloodstains, no phone calls, no suspects fleeing the country, no testimony. Just a couple of websites. People make stuff up on websites all the time. I wouldn't have assigned .999 probability to the hypothesis that there even was a trial if I hadn't heard of it (glancingly) prior to your post.

[edit: I'm referring only to responders who, like me, based their answer on a quick read of the links you provided. Of course more evidence was available for those who took the time to follow up on it, and they should have had correspondingly higher confidence. I don't think your answer was wrong based on what you knew, but it would have been horribly wrong based on what we knew.]

comment by aausch · 2009-12-13T05:57:28.590Z · LW(p) · GW(p)

It might have been more useful to ask for confidence intervals around probabilities. Maybe that should become the standard around here?

That way, I imagine people who did not care so much about the topic/do as much research, would have had a way to indicate the fact.

Replies from: wedrifid, Jawaka
comment by wedrifid · 2009-12-13T06:39:25.074Z · LW(p) · GW(p)

It might have been more useful to ask for confidence intervals around probabilities. Maybe that should become the standard around here?

No! In this context confidence intervals around the probability have no meaning!

I do agree that adding extra information about confidence is important for things like this. It's just that this isn't a case for which confidence intervals (approximately) work. It would make more sense if the probability was a property of the universe itself, then you could establish bounds on where the 'true probability' lies (as discussed with komponisto).

Replies from: saturn
comment by saturn · 2009-12-13T08:14:51.663Z · LW(p) · GW(p)

No! In this context confidence intervals around the probability have no meaning!

Why can't they be confidence intervals around the probability after doing [some amount] more research?

Replies from: Vladimir_Nesov, wedrifid
comment by wedrifid · 2009-12-13T08:20:12.729Z · LW(p) · GW(p)

Why can't they be confidence intervals around the probability after doing [some amount] more research?

That you can do.

comment by Jawaka · 2009-12-13T11:30:39.611Z · LW(p) · GW(p)

I feel the same way. I set the probabilities to 25 (not G alone) / 75 (G alone) after half an hour of reading, just because I wanted to have room to be more confident after 2 hours of reading.

comment by Blueberry · 2009-12-13T07:16:33.889Z · LW(p) · GW(p)

these two things constituting so far as I know the entirety of the physical "evidence" against the couple

I'd like to know your reaction to this argument. There is some other evidence against the "lone wolf" theory and pointing more towards Amanda, specifically that Meredith's bra was removed and the scene rearranged after her death (and not by Rudy), the bloody footprints that match Amanda, and the witness placing all three of them together near the house around the time of Meredith's death.

(Edited to fix formatting)

Replies from: McJustice, komponisto, Jawaka
comment by McJustice · 2010-01-03T00:06:06.214Z · LW(p) · GW(p)

Why not by Guede? There is no evidence of him leaving right away only supposition. He was next seen at 2AM in a Disco. He is a known burglar and his bloody fingerprints are on Meredith's purse and also he had expressed interest in Meredith to other people prior to that night. He was there for money and also for sex if he could get it. It is perfectly consistent with what is know that he could have stayed and carried out his probable 2nd intention... having sex with her... something he could only accomplish after she died. After a clean up of the mess left when a recently deceased person relaxes certain muscles and voids waste which took long enough for blood to dry and certain marks to become fixed on the body. He may have gone to the other toilet during this time. After a while he returned to her the bra strap was cut and her body rearranged to facilitate sex. He wore condoms and left internal DNA traces either from his fingers or from the outer surface of the condom from when he handled it... After that he did a quick clean of himself and the bathroom.... it is interesting that the people who saw him at the disco later stated that he STANK.

There are no bloody footprints that match Amanda's. None. No blood found on alleged footprints in the hall therefore not linked to the murder. The shoeprint in the bedroom originally thought to match her shoe size were on cloth that had a crease that made the print appear shorter and it later was found to be consistent with the distinctive shoes that Guede wore. The bloody print on the bathmat has toe and arch characteristics that are again consistent with Guede's and not the others.

Besides the original coroner's conclusion was that there was only one attacker. He was fired from the case and replaced by a new coroner who had a new finding more in agreement with Mignini's theory of a group attack.

comment by komponisto · 2009-12-14T07:34:46.654Z · LW(p) · GW(p)

Does this kind of evidence have anywhere near 30 bits of inferential power?

To me, it seems more like on approximately the same order as psychological evidence.

comment by Jawaka · 2009-12-13T11:03:26.610Z · LW(p) · GW(p)

Have you read the counterarguments from "Friends of Amanda"?

Replies from: Blueberry
comment by Blueberry · 2009-12-13T18:56:04.859Z · LW(p) · GW(p)

I looked at that site but I didn't see specific counterarguments addressing that point.

comment by Seth_Goldin · 2010-03-24T03:23:41.819Z · LW(p) · GW(p)

I'm a little late to this game, but I spent over an hour, maybe two, comparing the information from the two websites. I had known nothing previously about the case.

My answers: 1: 0.05; 2: 0.05; 3: 0.95; 4: 0.65

So, I feel pretty vindicated. This was a great complement to Kaj Sotala's post on Bayesianism. With his post in mind, as I was considering this case, I assigned probabilities to the existence of an orgy gone wrong as against one rape and murder from one person. There is strong Bayesian evidence for Guédé's guilt, but it's exceedingly weak for Sollecito and Knox. This has really helped the idea of Bayesianism "click" for me.

komponisto, your reasoning is wonderfully thorough and sound. I can corroborate that I deliberately found myself "shutting the voice out" concerning the activity with the mop. You have a great explanation, overall. These two posts of yours are in the running for my all-time favorites.

Replies from: komponisto
comment by komponisto · 2010-03-25T05:53:30.043Z · LW(p) · GW(p)

Thanks for the kind words!

Actually, looking back, I now think I could have done better. In particular, I wish I had been more explicit about the central probability-theoretic point: the fact that the evidence against Guede screens off Kercher's death as evidence against Knox and Sollecito. This point was missed by a number of commenters; if you read the discussion you'll find various people saying that the prior probability "should" take into account the fact that a murder occurred in Knox's house. In actuality, of course, it doesn't matter where you start, so long as you eventually incorporate all of the relevant information; but what must be understood is that if you start with probability mass assigned to Knox and Sollecito because of Kercher's death, then you have to take (most of) that probability mass away upon learning of the evidence against Guede. In other words, under this setup, evidence of Guede's guilt becomes evidence of Knox's and Sollecito's innocence -- something which is counterintuitive and very easy to forget (with tragic consequences).

This issue of "choosing the prior" and other Bayesian subtleties encountered in these discussions may be worth revisiting at some point.

Replies from: redlizard
comment by redlizard · 2013-08-17T00:32:40.096Z · LW(p) · GW(p)

In particular, I wish I had been more explicit about the central probability-theoretic point: the fact that the evidence against Guede screens off Kercher's death as evidence against Knox and Sollecito.

I think this insight warrants a great amount of emphasis. The fact that Kercher's death is screened off by some factor unrelated to Knox and Sollecito means that the question of whether the given evidence against Knox and Sollecito is sufficient to judge them co-conspirators is equivalent to the question of whether the given evidence against them would have been sufficient to judge them murder-conspirators in the absence of a body. And I don't think anyone believes THAT is the case.

comment by komponisto · 2010-01-20T14:09:28.144Z · LW(p) · GW(p)

On the "liar" issue, and the implication of Lumumba:

What numerous people (not here, for the most part, but with some exceptions) have been either forgetting or ignoring, almost to the point of obstinacy, is that Knox did not come up with Lumumba's name spontaneously. She and Lumumba had exchanged text messages on the night of the killing; in one of them, Amanda wrote "see you later". Her interrogators questioned her aggressively about this correspondence, clearly with the implication that Lumumba (as well as Amanda herself) might have been involved in the murder. The idea of Lumumba's guilt was planted in her head by the police. Knox's "accusation" of Lumumba amounted to no more than saying "Well, all right, I guess maybe he could have done it."

To "lie" is to make an assertion that one knows to be false. Amanda Knox was unambiguously clear about the fact that her "story" about Lumumba being the killer was a dreamlike vision, not an actual claimed memory. It does not constitute a positive assertion about the state of the world, and thus cannot be a "lie". Now, definitions don't matter, of course; but the point is that the lack of correspondence between this particular account and the actual reality of the situation is not Bayesian evidence of her having wished to deceive police about her state of knowledge (which would in turn be Bayesian evidence of her guilt).

Replies from: shuttlt
comment by shuttlt · 2010-02-09T18:32:40.594Z · LW(p) · GW(p)

"Knox's "accusation" of Lumumba amounted to no more than saying "Well, all right, I guess maybe he could have done it."" I don't want to cause you to rehash arguments you've had here already. There are so many other pieces of evidence of equal value as her 'lie'. I am aware of the circumstances under which Lumumba was mentioned. At the moment all we can say about the circumstances are that she says she was slapped twice on the back of the head and shouted at, they say they didn't. Perhaps evidence will be produced by one side or another at the slander hearing. It's clear though that she, or possibly her family, has been less than truthful about the length of time she was interrogated for.

As for her statement about Lumumba. She said it in her interview ending at 1:45, she repeated it in her statement finishing at 5:45, she repeated it in the "gift" she wrote the following day. Admittedly it is all couched in the "half remembered dream" language of hers.

"To "lie" is to make an assertion that one knows to be false" True. I think she is lying. I find it very difficult to believe that in hour ever much of the hour and fourty five minutes of questioning remained after they got onto the text message she became so confused that for two weeks until Lumumba's alibi came good she was unsure whether what she had said about having been there and listened to Meredith's screams was a dream or a half remembered truth.

"It does not constitute a positive assertion about the state of the world, and thus cannot be a "lie"." Philosophically I agree with you. I just don't think it was sensible of her to make, and then repeat, statements to the police that one has to defend on the grounds that they are do not consitute positive assertions.

"Now, definitions don't matter, of course; but the point is that the lack of correspondence between this particular account and the actual reality of the situation is not Bayesian evidence of her having wished to deceive police about her state of knowledge (which would in turn be Bayesian evidence of her guilt)." How about the false alibi about the party, and the false alibi of using the computer? How many innocent people get caught in two false alibi's? I'm excluding the alibi where she said she was home all night and he said she went out.

comment by gate · 2009-12-23T07:58:18.446Z · LW(p) · GW(p)

Rudy Guédé's won his appeal. His sentence has been reduced to 16 years -- ten less than Knox and nine less than Sollecito.

Funny world.

I have no opinion on the guilt or innocence of Knox or Sollecito. I've read the biased accounts of the evidence with amazement. I assumed Guédé's guilt was obvious. Kinda speechless over this new twist. While I can imagine someone thinking all parties were equally guilty, I am unable to find any rationale for deeming Guédé less guilty.

Replies from: Feh
comment by Feh · 2009-12-24T09:04:15.919Z · LW(p) · GW(p)

Rudy chose the "fast track" option, which allows for a one third reduction in prison term, and so that's why his sentence was reduced. I don't really understand their system enough to criticize it, but it seems to me that guilty criminals generally would choose the "fast track" option, and get reduced sentences, whereas the innocent generally would choose the full trial, and get full sentences.

comment by JRMayne · 2009-12-16T03:19:21.815Z · LW(p) · GW(p)

The error here is even asking a question about Amanda's motivations when you >haven't established an evidentiary (and that means physical) trail leading from >Meredith's body to Amanda's brain.

Indeed, that's counterintuitive. I believe it to be counterintuitive because it is incorrect. Amanda Knox was a roommate of Meredith Knox's; the initial likelihood of her being responsible is raised by that fact alone. It is normal for police to question motives of people close to the decedent, and it is good practice.

Suppose Hubby ends up shot a few dozen times as he is bicycling home from work. Wife has an alibi - she was 30 miles away, on film, at the time. But wife, after 20 minutes of questioning, confesses to giving $3,000 in cash she had squirreled away to someone (a description, but no name and he's gone) to shoot Hubby, that she gave him Hubby's route, and she was mad at Hubby for his affairs, affairs investigators later confirm.

Is the confession noise? We have no physical evidence. That's somewhat dissimilar to your assertion, I understand. Let's take it back a step:

Let's keep Hubby shot dead, but Wife does not confess. However, she has a $45,000 withdrawal the day before. She says it was for "baking supplies," but she lost it somewhere and can't find the cash. She says that she dearly loved Hubby, but she has dates from match.com that she set up the week before. When the cops get there to tell her about Hubby 15 minutes after the shooting, all of Hubby's clothes and property are being placed in a Goodwill truck, and Hubby's car is on sale at E-bay and there's champagne on ice.

I don't think that's noise.

And I don't think Amanda Knox's behavior is valueless noise. The argument made that the lack of physical evidence is far more telling may be sound (depending on the actual evidence), but the behavior is evidence.

Potential Bias Alerts: I'm a prosecutor. I have had my cases dissected in the press (one case may end up on TV) and not always accurately. Circumstantial cases with a high degree of detail are often difficult for the press to get right, in my experience. Highly-charged sex cases are often difficult for the press to get right, in my view. I have no experience with Italian authorities, and probably impute similarities to American justice that do not exist. I do give some value to the jury's verdict, because I do not believe that the time I've spent looking at the evidence is anywhere near sufficient.

Replies from: AnnaGilmour, AnnaGilmour
comment by AnnaGilmour · 2009-12-16T17:00:26.874Z · LW(p) · GW(p)

micio quoted:

"while Knox's defenders have no trouble complaining that jurors judged her unfairly based on her behavior in the days after the murder (purchasing sexy lingerie, frolicking around town and making out with her boyfriend), they don't mind pointing out her gentle appearance - or arguing that she has a reputation for being "sweet and generous and kind" etc. In other words - they're fine with exploiting Knox's image only to the extent it lines up with the idea that she's "not the type" who could kill another human being in connection with an act of sexual violence"


After a while people will be accountable for the evidence they choose to acknowledge or not. Things like this are inconsequential and incidental. Stick to the evidence. Talk about that. You will be voting for civilization and the rule of law or rule by thugs.

What I am finding is that a few people who are commenting here are consistently making the mistake that komponisto described. They are not leaving their perceptual fallacies.

For instance this statement:

"Amanda Knox was a roommate of Meredith Knox's; the initial likelihood of her being responsible is raised by that fact alone. It is normal for police to question motives of people close to the decedent, and it is good practice."

First of all, if the roommate question is enough to bring her in for questioning, then it should be on the same level as the inquiry toward the other two roommates, and this also puts Raffaele further out on the proximity scale. But these checks should be quick and cleared by the lack of physical evidence.

And this statement:

"Wife...confesses to giving $3,000 in cash she had squirreled away to someone (a description, but no name and he's gone) to shoot Hubby... Is the confession noise? We have no physical evidence. That's somewhat dissimilar to your assertion, I understand. Let's take it back a step..."

This has been checked as well. Given the lack of physical evidence, then evidence of conspiracy or collusion gets checked. There was no evidence of this either.

And the following statement:

"...but the behavior is evidence."

Not when there is no evidence of conspiracy, collusion, or physical evidence because then you are going back to the mistakes described by komponisto in the post.

Replies from: wedrifid
comment by wedrifid · 2009-12-16T20:48:47.853Z · LW(p) · GW(p)

Use a '>' at the start of a paragraph that is a quotation

so it will look like this.

comment by AnnaGilmour · 2009-12-16T16:57:08.227Z · LW(p) · GW(p)

After a while people will be accountable for the evidence they choose to acknowledge or not. Things like this are inconsequential and incidental. Stick to the evidence. Talk about that. You will be voting for civilization and the rule of law or rule by thugs.

What I am finding is that a few people who are commenting here are consistently making the mistake that komponisto described. They are not leaving their perceptual fallacies.

For instance this statement:

"Amanda Knox was a roommate of Meredith Knox's; the initial likelihood of her being responsible is raised by that fact alone. It is normal for police to question motives of people close to the decedent, and it is good practice."

First of all, if the roommate question is enough to bring in for questioning, then it should be on the same level as the inquiry toward the other two roommates, and this also puts Raffaele further out on the proximity scale. But these checks should be quick and cleared by the lack of physical evidence.

And this statement:

"Is the confession noise? We have no physical evidence. That's somewhat dissimilar to your assertion, I understand. Let's take it back a step..."

This has been checked as well. Given the lack of physical evidence, then evidence of conspiracy or collusion gets checked. There was no evidence of this either.

And the following statement:

"...but the behavior is evidence."

Not when there is no evidence of conspiracy, collusion, or physical evidence because then you are going back to the mistakes described by komponisto in the post.

comment by AnnaGilmour · 2009-12-15T17:32:20.390Z · LW(p) · GW(p)

http://www.casavaria.com/cafesentido/2009/12/05/5268/amanda-knox-sentenced-to-26-years-in-italy/

These are the concerns as delineated. From the above linked blog.

"The case for appeal is complex and rests on several very firm claims of prosecutorial misconduct:

1.The defense was denied the opportunity to present its own DNA experts;

2.A neurologist acting as witness for the defense testified that Knox could have been subjected to such intense stress, between the horror of the killing and police intimidation that she falsely remembered details that initially implicated her former boss;

3.Allegations of police intimidation and misconduct were not investigated;

4.DNA evidence appears shoddy, and is the sole source of evidence linking Knox in any way to the crime;

5.Mignini, the chief prosecutor, stands accused of criminal abuse of office;

6.Mignini threatened and began to carry out a rigged prosecution against a journalist whose coverage he disliked;

7.Press were allowed to influence jurors and judges in the case;

8.There is evidence police knowingly presented false evidence, fabricating unsubstantiated theories of the crime;

9.There are questions about the legitimacy of imprisoning Knox for two years before even bringing her to trial;

10.Jurors may have slept through defense testimony, flagrantly ignoring facts of the case that conflicted with prosecution claims;

11.The prosecutor openly announced his determination that the trial should be treated as a guilty unless proven innocent process: investigation of possible collusion between the prosecutor’s office and the presiding judges were never properly investigated."

comment by ABranco · 2009-12-14T19:52:44.495Z · LW(p) · GW(p)

I haven't deeply read or studied the whole case itself — but by all means this is a beautiful, detailed, clearly written exposition of your train of thoughts. Thank you.

And yes, the mental suffering of spending two decades in jail + being despised by everyone around when you're actually innocent shouldn't be easy to face even with the highest possible dose of stoicism one could inject herself.

comment by komponisto · 2009-12-14T06:00:07.870Z · LW(p) · GW(p)

Post now revised in light of comments.

Replies from: None, Jack
comment by [deleted] · 2009-12-14T07:34:16.797Z · LW(p) · GW(p)

I posted this in response to the Hacker News thread but i wanted to cross-post it here. I appologise for not having read all the comments here first before responding. It seems your post is largely misrepresenting the facts of the case.

Have you read the judge's summary?

http://www.zimbio.com/Amanda+Knox/articles/58/Understanding+Micheli+2+Judge+Micheli+Rejected

A few key points in the prosecutions case:

  • 4 mixed DNA samples of the Knox and Kercher. Bloody footprints that match. Blood on the tap put Knox at the crime scene that evening or in the early morning.
  • A bloody bra in the washing machine
  • Attempts to frame an innocent man for the crime.
  • Repeated lying to authorities regarding her whereabouts. Still no fixed alibi.
  • Knox and Kercher's house was cleaned with bleach.
  • Sollecito's trainers were cleaned with bleach. A defect in the sole match a blood print on the scene. The decision went through going through 19 expert judges and 6 lay judges. Conviction was unanimous.
  • Eye witness putting all 3 suspects together outside the cottage that night, and the night previous.
  • Knox and Sollecito standing outside the crime scene when the police arrived with mop and bucket.

Certainly, we can ignore some of the strange behaviour of the convicted (the phone calls, the lies, her past). But the case is much stronger than what this article makes out. It's also worth pointing out that various aspects reported in the media aren't correct - such as the 14-hour interrogation and police violence.

Rational thought takes anyone first to the conclusion that there was more than one killer. Guede left the scene soon after the murder (eye witness reports; evidence of cleaning, Guede's own statement). It is clear the crime scene was later returned to, and altered to cover evidence (faked break-in; footprints; removal of bra from the body). With all the additional evidence against Knox and Sollecito, physical and circumstantial, clear motive, and consitantly irrational behaviour, gives a very strong prosecution case.

Whether they are guilty or not isn't for me to say, nor would i think i'm qualified enough to give such probabilities. But the case appears to be largely misrepresented in your blog post.

Replies from: rmattbill
comment by rmattbill · 2009-12-14T18:21:07.493Z · LW(p) · GW(p)

Hi Nick, While I appreciate that you don't seem to be one of the irrational Knox haters, your comments about the evidence contain a couple of errors, and the one that don't leave out some important facts which cast doubt on almost every single claim.

-Yes, Knox's DNA was founded mingled with Kercher's, but almost all of it was in the bathroom they shared. It would've been almost impossible NOT to find a few instances of their DNA mixed in such a small place, and a place where humans shed copious amounts of hair and skin cells, and even blood (shaving cuts, etc.).

-Not one shred of Knox's DNA was found in Kercher's room. The idea that she somehow managed to remove every microscopic shred of her DNA, while leaving Rudy Guede's behind, is completely implausible. This alone casts enormous doubt on the prosecution's theory. DNA in the bathroom simply proves Knox and Kercher lived together. A total lack of DNA in Kercher's room is compelling evidence she was not at the scene of the crime.

-No traces of bleach were found at the crime scene. Numerous rumors about bleach are clogging message boards all over the internet, including false stories about receipts which showed Knox buying bleach twice the morning after the murder, but those stories did not pan out and were not presented at trial. One witness emerged, seven months AFTER the murder, to say he saw Knox buy bleach in his store, but his co-worker said he was lying. This testimony must be treated skeptically, since no traces of bleach were found at the crime scene. The crime scene was extensively examined using Luminol, and in addition to revealing blood, Luminol illuminates trace amounts of bleach.

-The Albanian witness who says he says Knox and Sollecito with Guede is the only person to allege that the three knew each other, and his testimony at the trial was contradictory and underwhelming, to say the least. Throughout his interrogation and trial, Guede denied knowing Knox or Sollecito, and denied they were at the house. He knew what Amanda looked like, as he had twice visited the downstairs neighbors to play basketball, but didn't even know what Sollecito looked like.

-Knox and Sollecito had taken the mop to Sollecito's house to mop up water that had come from a broken pipe under the sink. Was any blood or DNA found on the mop?

-Whether or not the bloody footprint on the bath mat matches Sollecito or Guede is highly debatable. Another bloody footprint, found in Kercher's room, was a definitive match for Guede. Although people have posted claims about bloody footprints revealed using Luminol, those prints were left by sweat and oil, and tested negative for any trace of blood.

Briefly, on a few other points, the prosecution's fingerprint expert said it was not unusual that he didn't find usable prints for Knox in her own bedroom. There were lots of smeared prints (fingerprints, made by a tiny amount of oil on our skin, are easily disturbed), just no USABLE prints. Lots of smeared and partial prints is evidence the room was NOT wiped down, and he testified he saw no evidence of a wipe down.

Last, the so-called "fake" break-in is highly contentious issue and neither conclusion can be viewed as beyond doubt. The prosecution tried to say it's impossible to climb the wall (ignoring photos of a 40-year old Italian detective in dress slacks and dress shoes easily scaling the bars on the window below), but Judge Micheli dismissed them, noting that anyone in reasonable shape could've easily climbed into the window. Rudy Guede, who had committed at least three burglaries in the previous week, was 20 years old, and a former semi-pro athlete.

But again, I appreciate your rational approach to the evidence, and respect your opinion. It's nice to see someone on the internet talking about the evidence, and not just Knox's immature behavior.

Cheers, Matt

Replies from: Jack, None
comment by Jack · 2009-12-14T20:05:23.935Z · LW(p) · GW(p)

Rudy Guede, who had committed at least three burglaries in the previous week

Jeeze, how did I miss that. Do you have a link?

Edit: Also. New people! Welcome.

Replies from: rmattbill, AnnaGilmour, AnnaGilmour
comment by rmattbill · 2009-12-14T23:37:57.360Z · LW(p) · GW(p)

Sorry, my post contained an error. It was three burglaries in five weeks, not one week.

This is from an article at the Daily Mail entitled "Amanda Knox: The Troubling Doubts Over Foxy Knoxy's Role in Meredith Kercher's Murder."

Here's the link: http://www.dailymail.co.uk/news/article-1234298/Amanda-Knox-The-troubling-doubts-Foxy-Knoxys-role-Meredith-Kerchers-murder.html

And the pertinent text from the article:

On September 27, 2007 - five weeks before the killing - Perugia bar tender Cristian Tramantano heard a noise downstairs in his home and found Guede wandering around with a large knife. Tramantano recognised Guede from his work in a nightclub.

There was a confrontation between the two, which ended when Guede ran away. On four occasions, Tramantano went to Perugia's central police station to report the break-in, identify Guede as the culprit and to detail how the intruder was armed and threatened him.

On each occasion, he says he was ignored and the police refused to log his complaint.

The following weekend, there was a break-in at an English-speaking nursery school in Milan in which 2,000 euros and a digital camera were stolen. The school owner, Maria Antoinette Salvadori del Prato, reported it to her local police station.

Three weeks later, on Saturday, October 27 - one week before the murder - Mrs Prato arrived at the school early in the morning with a locksmith to replace the front door, only to be confronted by Guede standing in the main entrance.

Police were called and Guede questioned. A stolen laptop, digital camera and ten-inch kitchen knife were found in his backpack.

But instead of being arrested and charged, Guede was merely escorted to Milan central railway station and placed on a train back to Perugia.

In the interim, on the weekend of October 13, there had been a break-in at the office of lawyers Paolo Brocchi and Luigi Palazzoli, in which a firstfloor window was smashed - similar to the break-in at Meredith's house. A computer and other items were stolen.

They were later found in Guede's possession, but he was not arrested or charged.

Replies from: zero_call, AnnaGilmour
comment by zero_call · 2009-12-14T23:46:00.659Z · LW(p) · GW(p)

The Daily Mail is a British tabloid... frequently posting completely fraudulent information about football players, for example... check your sources friend...

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T00:59:20.179Z · LW(p) · GW(p)

The above quoted story was reported in more than just the Daily Mail. I will look for a few of the other articles.

comment by AnnaGilmour · 2009-12-15T00:57:58.986Z · LW(p) · GW(p)

I read three in the week leading up to the murder, as well. I should recheck that. But it is confirmed that he traveled with a 16 inch knife "for protection" and that he had various run-ins resulting in complaints to police that were ignored by the police.

comment by AnnaGilmour · 2009-12-15T17:14:17.616Z · LW(p) · GW(p)

For the most horrible information about Guede, read his journal. Not fun to read, as it is very dark, but reveals a telling psychological profile as well as shows his time line the night of the murder. His Skype conversation as well gives a lot of information.

On the other hand, if you read Raffaele's writing, it shows his innocence.

comment by AnnaGilmour · 2009-12-15T00:29:12.584Z · LW(p) · GW(p)

Yes... a huge fact that did not hit the headlines in any big way.

Replies from: Jack
comment by Jack · 2009-12-15T02:33:18.782Z · LW(p) · GW(p)

I'm still waiting on non-tabloid verification. A quick look at the paper's wikipedia page yields a long list of successful libel suits.

Replies from: AnnaGilmour, AnnaGilmour, AnnaGilmour, AnnaGilmour
comment by AnnaGilmour · 2009-12-15T17:11:00.785Z · LW(p) · GW(p)

Just one more comment. One more article, includes someone who knows Rudy who said he used cocaine.

http://www.telegraph.co.uk/news/worldnews/europe/italy/2976474/Meredith-Kercher-murder-trial-Rudy-Guede-was-violent-to-women.html

comment by AnnaGilmour · 2009-12-15T16:19:32.375Z · LW(p) · GW(p)

Sorry... I'm in the Pacific Time Zone... Just got back to the computer... I am looking into non Daily Mail/Mirror articles. Am at work, so have to look as I can. I do know it was part of the court record and that the kindergarten teacher testified and a police person might have as well. I am looking for something on the court record. Candace Dempsey of the Seattle Post Intelligencer was following that aspect of the case and wrote about it in her blog Italian Woman at the Table. Guede's criminal history is established as fact, as well as the police turning away reports about him.

comment by [deleted] · 2009-12-14T21:42:15.627Z · LW(p) · GW(p)

Thanks for taking your time with your thoughtful and detailed response. I will go through each point in turn below. It's worth mentioning now that I don't actually mean to argue for or against the conviction specifically; rather I feel the prosecution case is significantly stronger than US media has generally reported. Also I'm neither a lawyer, phorensic scientist or logician, so I apologize in advance for any technical mistakes. I'm just trying to assess the information myself that's available on the internet and come to an informed opinion.

Certainly some of the evidence appears flawed: the bra clasp, the alleged murder weapon, the eye witness. But we do know that the Judge, and a panel of 19 legal experts, admitted these as evidence. I can't really comment on whether the blood trace on the knife, for example, is sufficient enough to admit the evidence; similarly whether the bra clasp can become contaminated. But the evidence was admitted, and strongly contested, consider and eventually accepted by the panel and the jury.

  • The DNA evidence: Firstly, I think the important point is that 4 blood samples from the bathroom were found with mixed Knox-Kercher DNA. From truejustice.org: " Yes, it does seem that the investigative methods were sloppy and not all samples may be reliable (I acknowledge that there are some problems with the prosecution’s case). But I have yet to read even one article where a reputable DNA expert can explain why sloppy police procedures would result in four separate mixed blood samples".

  • Also this site (http://www.thedailybeast.com/blogs-and-stories/2009-05-24/will-dna-damn-amanda-knox-/), reporting on the Forensic biologist Patrizia Stefanoni testifying for 9 hours on the stand, notes "But perhaps more damning even than the knife was Stefanoni’s testimony that a mix of Knox’s DNA and Kercher’s blood was found on the floor in the bedroom of a third roommate, Filomena Romanelli [...] her window was broken with a large rock that prosecutors believe was used to stage a break-in. The mixed Knox-Kercher trace was found after investigators used luminol, a substance used in forensic science to bring out blood that had been cleaned up."

  • The bleach: The truejustice.org site has various mentions of use of bleach on the alleged murder weapon, shoes, and apartment (not crime scene), such as "A police officer who led a search of Sollecito’s apartment added weight to the prosecution’s assertion that the double DNA knife had been cleaned with bleach. He testified that he had been struck by 'the powerful smell of bleach'.". I agree this is far from damning evidence of a cleanup, and the lack of the recipe being produced at trial weakens this evidence substancially.

  • The Albanian witness: From the translation of the Micheli report, "Judge Micheli examines the evidence of Hekuran Kokomani and finds him far from discredited .. Hekuran Kokomani was in the vicinity of the cottage on both 31st Oct. and 1st Nov isn’t in doubt ... details which he gave of the breakdown of the car, the tow truck and the people involved weren’t known by anyone else.".

  • The police who found Knox and Sollecito at the crime scene were a different police force there on other business (the mobile phone/bomb hoax), so I assume at the time they didn't think much of it and so the mop wasn't detained as part of the crime scene. Sollecito said it was being used to mop up water that had come from a broken pipe under the sink; knox said it was to mop up water from the pasta spilt cooking the night before. Sollecito later sent an email saying they ate something other than pasta that night.

  • Your point that there were no bloody footprints that fit Knox/Sollecito doesn't match with what I'm reading from the report, including "bloody bare footprints which show up with luminol and fit Knox’s and Sollecito’s feet" by the front door, suggesting entry through that route, and "Bloody footprints made visible with luminol in Filomena’s room contain Meredith’s DNA". The source of this is all truejustice.org, but supposedly this is based on impartial translations of the freely available italian report. I have no other source to go on and don't speak Italian, do you think these are falsehoods? Are there alternative translations/summaries available?

  • Regarding the 'fake break-in', how did the defence respond to the claim that glass lay on top of clothes that had been disturbed during or after the attack?

  • Only final point, "Rudy Guede, who had committed at least three burglaries in the previous week", is there a source for this information?

Replies from: rmattbill, rmattbill
comment by rmattbill · 2009-12-15T07:35:41.566Z · LW(p) · GW(p)

Two more tidbits re: Kokomani (from annebremner.com):

To give you an example of how absurd it got, Kokomani said that when Amanda was yelling at him, he noticed a wide gap between her front teeth. So the judge asked Amanda to smile, and she did. There is no gap between her front teeth.

Nor could Kokomani have had a beer with Amanda and her Italian uncle in July of last year, as he claimed in court, because Amanda was not in Italy at that time and she does not have an Italian uncle.

comment by rmattbill · 2009-12-15T02:22:37.870Z · LW(p) · GW(p)

Hi Nick,

Thanks for the response.

Regarding the bleach, no evidence was ever presented that anything had been bleached. This story took on a life of it's own after the phony receipts story began circulating. I believe the Judge blocked at least one officer from testifying that he smelled bleach, and was only allowed to say that Sollecito's apartment smelled "clean," because the bleach smell was not listed in the initial report, and was added later, after the false reports about the receipts.

Despite the deference True Justice shows for every bit of evidence that favors Knox's guilt, Kokamani's testimony was ludicrous. He claimed that when he saw Knox, Sollecito and Guede together, that Sollecito (a meek computer nerd by all acounts), punched him in the face, and that Knox whipped out a 16 inch (!!!) knife, and said "Come here you! I'll show you!" and that he escaped by hurling olives and a cell phone at her. His testimony contradicted his original statement on many key points, and he had been arrested on drug charges before his testimony.

Regarding the footprints, my understanding is that two bloody shoe prints were found. One in Kercher's room that matched Rudy Guede, and another on the bath mat in the bathroom, that was a partial. From everything I've read, the partial print in the bathroom is a mess. It's certainly hard to tell anything from the photos. At various points, the prosecution said it was Knox's, then Guede's, then Sollecito's. The defenses expert witness made a strong case that it was Guede's, but I don't think anyone can conclusively prove anything one way or the other because it's only a partial print.

The other footprints were revealed by Luminol, but what True Justice leaves out is that every single one (except for the two I mentioned above), tested negative for the presence of blood. If the footprints weren't bloody, they don't really say anything about the crime, especially since Knox and Sollecito admit to being in the house that morning, before the body was discovered.

There are two good papers on the footprints at friendsofamandaknox dot org. Of course they're biased in Amanda's favor, but not any more so than True Justice is in the other direction.

I'm not surprised that some of Kercher's blood was mixed with Knox's DNA in the bathroom, since Knox's DNA could've come from anything. If a drop of blood splashed onto a dead skin cell of Knox's, the result would've been DNA from both women in the drop of blood. And that doesn't take into account the sloppy (by U.S. standards) forensics work done by the Italian police who could've easily, and innocently, intermingled DNA which is, often, invisible to the naked eye.

This is apparently what happened with the bra clasp which was left sitting on the floor for 47 days, was moved several times by unknown persons, and contains the DNA of at least three other people (and those people are not Kercher, Knox, Guede, or the other roommates or their boyfriends). The DNA either belongs to police who were not following procedure, or was picked up in the lab due to improper handling.

In the crime scene photos, it doesn't appear there is any glass on top of the clothes, nor did the police present photos of such a thing at trial. One of the biggest misconceptions is that the glass was on top of Kercher's clothes in her room. If this is true, the intruder could hardly have ripped Kercher's clothes off before breaking in through the window, but in fact the clothes were in Filomena's room. She testified she didn't leave any clothes out, hence the claim the break in was staged. But Filomena also could be wrong, she certainly wouldn't be the first witness to misremember something. Also, Filomena was allowed into her room no less than three times before the police finally sealed it, so it's hard to say exactly how the clothes and glass were intermingled before they were disturbed. It's possible the break-in was staged, but given Guede's past burglaries, and Occam's Razor, it seems likely that Guede broke into the house. If the break-in was staged, the prosecution did not manage to prove it beyond a reasonable doubt, at least not to my mind.

Last, I posted a separate comment with the link to the Daily Mail story about Guede's other break-ins.

Replies from: None, pataz1
comment by [deleted] · 2009-12-15T16:26:36.227Z · LW(p) · GW(p)

You seem to be privy to a lot of information that I'm not, were you at the trial, or otherwise have better knowledge that the sourced information on the internet? Or is it from reading the 100-page Judge's report of the Guede case? I haven't heard before many of the things you've mentioned in your previous post. Also, some of the things seem to contradict what I've quoted above, a lot coming from the translation of Judge's summary. For example:

  • " I believe the Judge blocked at least one officer from testifying that he smelled bleach"

  • The specific details of Kokamani's testimony.

  • Information like " At various points, the prosecution said it was Knox's, then Guede's, then Sollecito's".

  • The papers on friendsofamandaknox don't give any sources. How do we know the information is good? I'm sure we could level the same criticism to truejustice.org, but many of the details they have linked to outside sources.

  • That the mixed DNA can easily be explained away, and DNA can be easily contaminated (there are various expert witnesses at the Guede trial who state otherwise)

  • That the bra clasp contained DNA of 3 other people.

  • "it doesn't appear there is any glass on top of the clothes", this contradicts what I've read from the Judge's report. You then go on to explain how glass could have got on top of the clothes (filomena allowed back in to the room), so I'm not sure which you are stating?

  • Regarding the Daily Mail story - as other posters have mentioned, the Daily Mail certainly isn't a reliable news source, unfortunately. And in general, even a well respected media source alone probably isn't good enough as a source, given how misreported the case has been (like the bleach receipt, the 14-hour interrogation, etc)

So again, I'm still not sure the truejustice.org summary of the Judge's document on the Guede case should be considered reliable, do you doubt some of the points? I'm using this to base a lot of my reasoning.

If it is an accurate summary, then it represents the decision of a large panel of law experts, that disagree with many of your arguments. So it seems either you are suggested (a) this translation Judge's summary is inaccurate, or (b) you disagree with the decision of the Judge and panel on many key points. If it's (a), I would certainly like to read a better translation. If (b), why do you think you are better qualified to make decisions on forensic evidence than a panel of legal experts?

I think in the end I will have to wait 90 days for the summary of the case to be made publicly available to make my own decision on the likelihood of guilt. There are still great disparages between the "pro" and "con" sites about what happened in the court room, and exactly what evidence was and was not presented in court. You seem to disagree with the Judge's decisions in the G case a lot (that the break-in was not faked; that the DNA evidence is unreliable; that the eyewitness testimony should not be admitted as evidence). What we do know is that the Judge, along with a large panel of legal experts, did in fact accept this evidence. Is it not reasonable (and rational) for me to accept the decisions of experts in the field?

Replies from: pete22
comment by pete22 · 2009-12-15T17:57:40.333Z · LW(p) · GW(p)

I'm with Nick -- there are very few primary sources available in English, and none of the stuff people are linking to, even the articles in mainstream media, seems like a completely reliable source to me -- especially on all these he said/she said issues of what evidence was actually adduced in court and if so whether it was effectively refuted.

comment by pataz1 · 2009-12-16T23:42:04.076Z · LW(p) · GW(p)

Regarding luminol footprints, I've seen statements that essentially if the blood is so week that its only revealed by luminol, the its highly feasible that there won't be enough material to test for blood. Yes, the luminol can't prove the prints are blood. But they're there, only a few of them, in the immediate vicinity of the crime. As I posted in another post, what prompted police to look for them was the half-print in blood on the bath mat. Were were the rest of the bare foot-prints leading up to that bath mat? There weren't any visible in the bedroom, but smears could have wiped them away.

Applying rationality- If the footprints in the hall are Knox's from the shower that morning, then there must have been enough blood for knox to make 2 full left foot prints, yet so little blood that it wasn't visible to knox taking her shower, nor was there any sufficient amount to test for blood. Does that seem a rational argument?

If its some other substance, then the situation is that there just happens to be three bare foot prints limited to the area outside the door that are revealed in luminol, that are compatible with both Knox and Sollecito, but none other. That doesn't seem a rational argument either.

And regarding the floating DNA; there's sufficient Sollecito DNA floating around the house to be transferred to the bra clasp to be found "in abundant" measures, yet none really revealed elsewhere; yet the limited amounts congealed like a star being born to be found on the clasp. There's sufficient DNA of Knox to be found in multiple blood drops, including the bedroom with the breakin, yet we accept at face value the "no DNA in the bedroom" argument heard round the world.

As for the footprint comparison between Sollecito, Guede, and the Luminol print found at the friends of amanda knox website, I knew upon looking at it immediately that they were a little 'free' with resizing the prints of the defendants to fit the print on the mat. Knox and Sollecito have different sized feet, but they present them as the same.

comment by Jack · 2009-12-14T06:16:03.000Z · LW(p) · GW(p)

1.Small. Hardly different from the prior, which is dominated by the probability that someone in whatever reference class you would have put Amanda into on January 1, 2007 would commit murder within twelve months. Something on the order of 0.01 or 0.1 at most.

What information do these new priors reflect? Obviously 1-10% of upper-middle class female college students with no history of criminal activity won't commit murder over the next 12 months so I assume that these priors are taking something else into account- like the fact that she lived with a murder victim. But can you say what else you've included? (Or point me if you already have somewhere).

Replies from: komponisto
comment by komponisto · 2009-12-14T07:01:22.252Z · LW(p) · GW(p)

What's going on here is that I'm still trying to figure out how I want to revise that sentence. I may just go ahead and cross it out, since I think the whole issue of "what the prior should be" is a distraction.

EDIT: Done.

comment by Seth_Goldin · 2016-09-08T16:46:54.698Z · LW(p) · GW(p)

For those interested, Netflix has a new documentary out about the case: https://youtu.be/9r8LG_lCbac

comment by JohnBonaccorsi · 2014-02-03T09:23:00.021Z · LW(p) · GW(p)

Dear fellow-poster Desrtopa --

Something called a "karma problem" has prevented me from replying directly to your comment at 03 February 2014 08:52:06AM. In the hope you will spot it, my reply will be posted here. I'm afraid it's the last comment I'll have time for; your reply to it, should you choose to post one, will be the last word in our exchange.

Suppose that you were living in a rather more paranoid country, where the government suspected you of subversive activities. So, they took a current captive suspect, tortured them, and told them they'd stop if the suspect accused you. If the suspect caved, would you blame them for accusing you, or the government for making them do it?

I would hope my friends would know I would applaud their doing anything--even torturing me--to avoid being tortured themselves. That goes double for strangers.

PS At 02 February 2014 11:49:15PM, I wrote, with respect to Knox's accusation of Lumumba: "The utterance of such a false thing, outside, maybe, a literal torture chamber, is depraved." I withdraw the word "maybe."

PPS Let's consider your own personal experience, the stressful interrogation you underwent about the money you were suspected of taking. Were you tortured? Was Knox tortured? If Knox was of the view that she was tortured, she had a duty--not merely to herself but to everyone--to take the stand in her trial and say her story-changing and her accusation of Lumumba were products of torture.

Replies from: JohnBonaccorsi
comment by JohnBonaccorsi · 2014-02-05T04:01:17.971Z · LW(p) · GW(p)

Reply to myself:

I hereby withdraw every negative thing I have said about Amanda Knox at this website. In the period since I posted the comment immediately above, I could not drive from my mind a remark my fellow-poster Desrtopa made in a post at 03 February 2014 07:39:06AM. In effect, Desrtopa asked whether I would fault a person for giving changed-stories because of torture; if I wouldn't, why would I fault the person for giving changed-stories under interrogation so harsh that its effect on the person being questioned would be tantamount to that of torture? At the time, I avoided answering Desrtopa's question.

Just a few minutes ago, I read commentary by a "veteran FBI agent" named Steve Moore. The commentary was posted at http://www.injusticeinperugia.org/FBI7.html , which is a page of a website called Injustice in Perugia. Having known really nothing about interrogation before I read Moore's remarks--and having had no sense how a law-enforcement professional would evaluate various types of interrogation--I had no right to remark on Amanda Knox's performance under interrogation in this case. Moore's remarks have persuaded me of what Desrtopa was, in effect, asking me to consider, namely, that the interrogation of Knox was a disgrace. Moore's closing paragraph was as follows:

"This is an innocent college girl subjected to the most aggressive and heinous interrogation techniques the police could utilize (yet not leave marks.) She became confused, she empathized with her captors, she doubted herself in some ways, but in the end her strength of character and her unshakable knowledge of her innocence carried her through. It’s time that the real criminals were prosecuted."

In saying "the real criminals," Moore seems to have been speaking of the interrogators themselves. If that is, indeed, what he meant, I would say he used the right term.

Should the conviction of Amanda Knox be upheld, and should Italy request Knox's extradition from the United States, the U.S. government, I hope, will decline to extradite her. The U.S., in my estimation, should do much more that that to right the wrongs that have been done in this matter.

Replies from: komponisto
comment by komponisto · 2014-02-05T05:24:52.172Z · LW(p) · GW(p)

Congratulations on changing your mind!

You did it exactly right: you realized you lacked knowledge in a certain domain (interrogation, in this case), proceeded to learn something about it, and updated your previous opinions based on the information you received.

Less Wrong exists pretty much in order to help people become better at doing exactly that.

My hat is off to you, sir.

Replies from: JohnBonaccorsi
comment by JohnBonaccorsi · 2014-02-05T06:30:31.299Z · LW(p) · GW(p)

Thank you, komponisto. Congratulations to you on this fine essay. I think I must have first encountered it in December 2012, when I first learned of Less Wrong and came to see what the site was. Though I didn't do much to absorb the essay at that time, it stayed in my mind; the news the other day about Knox's re-conviction moved me to read it again. My mental process in response to that rereading has, in a sense, been recorded here, in my last few days' worth of exchanges with Less Wrong posters. When I posted my first comment in response to the essay, I wasn't sure it would be noticed, because the essay was more than four years old. Fortunately for me, Less Wrong's participants were paying attention.

comment by adrienm · 2010-01-16T01:08:52.391Z · LW(p) · GW(p)

Enter a comment here

Komponisto I have read your account and interpretations of the evidence, and am refreshed and somewhat relieved to finally find some sense of perspective regarding the events. I was troubled by the outcome of the trial, in my mind the events as they were presented simply did not correlate together. When events are correctly modelled, all additional evidence reinforces the hypothesis. Your Bayesian analysis brought a perspective to the likelihood of the various evidence aspects. The prosecutors presentation of the facts was full of inconsistencies. In addition perspective was not used in evaluating the various items of evidence against likely events. By creating such a fantastical scenario of an extreme sexual it seems the prosecution managed to distract the jury away from their normal perception of what is likely or otherwise to have happened. Note I am not implying such extreme acts of sexual behaviour are that uncommon, however I believe that amongst 20 year old female exchange students with normal family backgrounds, such extreme sexual practices are so rare as to be nonexistent. If one takes this view point and only then looks for evidence to support an event with such a high degree of improbability, then one needs to look for evidence that supports the claim far beyond that of any reasonable doubt. Certainly the circumstantial evidence presented to date is far too insufficient to outweigh this.

Replies from: bigjeff5
comment by bigjeff5 · 2011-03-02T19:08:02.462Z · LW(p) · GW(p)

Worse, there was no physical evidence of a forced sexual orgy, there was no evidence that Knox or Sollecito were interested in such an orgy, there wasn't even any evidence that they had the slightest inclination toward that kind of behavior.

In other words, it was a hypothesis drawn from nothing, created in order to support a larger hypothesis that was based on extremely weak evidence and made before a far more likely guilty party was known.

The massive amounts of evidence pointing to Guide should have made this possibility extremely unlikely, and without it there was absolutely no reason for Knox and Sollecito to be involved at all.

comment by AnnaGilmour · 2009-12-16T01:26:37.669Z · LW(p) · GW(p)

A fascinating look at Roman law versus Germanic:
"Italian Law and You - Welcome to the Jungle!" by Amanda Sorensen
http://www.bestofsicily.com/mag/art315.htm

comment by pete22 · 2009-12-14T20:52:49.121Z · LW(p) · GW(p)

By far the most important evidence in a murder investigation will therefore be the evidence that is the closest to the crime itself -- evidence on and around the victim, as well as details stored in the brains of people who were present during the act.

the evidence against Guédé is such that the hypothesis of her guilt is superfluous -- not needed -- in explaining the death of Meredith Kercher

I think you’re begging the question here. Those who are convinced that K&S are guilty seem to believe that the evidence from the crime scene itself suggests that Guede could not have been the only participant – i.e. his involvement does NOT completely explain the death of Meredith Kercher. They seem to believe this for two reasons:

  1. The various evidence at the crime scene itself of a clean up and/or staged break-in, things like the bra being cut off or the body being moved – hard to attribute to Guede because a. he wouldn’t have had time (is this true?), and b. little effort was taken to remove evidence against Guede himself, even very obvious things like flushing the toilet.

  2. I haven’t seen any commenters mention it here, but one of the anti-Amanda sites, in quoting the Micheli report, seemed to imply that Kercher’s injuries were inconsistent with a single attacker.

Your post appears to take for granted that these are not credible arguments, but they seem like a very significant part of the prosecution’s case – and the part that I found hardest to assess without English versions of the Micheli report and other source documents. Can you explain how you reached this level of confidence?

FWIW, I'm not an Amanda-hater …my prior probability of her guilt was 30%, and I'm ready to revise it down. I’m just not sure I fully understand your argument on this point.

Replies from: rmattbill, AnnaGilmour, komponisto, AnnaGilmour
comment by rmattbill · 2009-12-15T02:55:55.663Z · LW(p) · GW(p)

"little effort was taken to remove evidence against Guede himself, even very obvious things like flushing the toilet."

The assumption here is that Knox and Sollecito carefully removed their DNA, but did not remove Guede's. Isn't the more rational explanation for all of the evidence against Guede, and the lack of evidence against K&S, that Guede did it and K&S weren't even there, as they have always claimed, and as Guede claimed no less than 5 times?

Further, there's a lot of supposition about a "clean-up" floating around on the web, but no evidence of one. There's lot of talk about bleach, bleach receipts, bleach on the knife, etc., but no evidence was introduced to support any of these claims.

Another claim is no prints were found for Knox, therefore she must've wiped them down. This presumes, incorrectly as it turns out, that no unusable prints were found. In fact, lots of smeared, smudge, or partial prints were found. The prosecution's own expert witness on fingerprints, Giuseppe Privateri, testified he saw no sign of the place being wiped down for prints. There were lots of prints, just not a lot of usable ones, which is totally normal since the way we use our hands often causes the oils left behind to be smeared.

Also, to believe this theory of a clean-up, one has to believe that with Superman-like enhanced vision, Knox and Sollecito could see their fingerprints and DNA, and Guede's, and could selectively remove their without disturbing his. This seems far-fetched in the extreme.

In the bathroom, some of Kercher's blood was found mixed with Knox's DNA, probably from splashing onto a hair follicles or dead skin cell from Knox. Why didn't this happen in Kercher's room, where the orgy took place? No intermingling of sweat, saliva, or other bodily fluids- in an orgy?!?! It boggles the mind.

Last, a lamp from Knox's room, her only source of light, was found on the floor in Kercher's room, possibly put there by Guede as he tried to look for his possessions, or look for obvious signs. If Knox so carefully scrubbed Kercher's room she was able to eras every invisible spec of DNA, why would she leave her bedroom lamp behind?

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T16:23:21.772Z · LW(p) · GW(p)

The idea of a staged break in is unsubstantiated. There is a broken window. Mignini added the interpretation without evidence of such a thing. The two shards on top of the bed turned out to be polka dots on a piece of clothing.

comment by AnnaGilmour · 2009-12-14T21:02:35.267Z · LW(p) · GW(p)

One thing to remember is that Mignini fired the coroner doing autopsy investigation when that person said it was the injuries of a single perpetrator. He then hired someone who said it was more than one perpetrator. If you would like, I can find a link to back it up. So the original report said one person caused the injuries.

Replies from: Eliezer_Yudkowsky
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-14T21:16:51.164Z · LW(p) · GW(p)

Huh. I wondered if something like this might be the case, but then wondered if I was being selectively skeptical of the prosecution and trying to dismiss all of their evidence. Next time I'll remember to (a) trust myself a little more, and (b) remember that reality itself is consistent rather than fair, i.e., Knox obviously didn't do it, thus if the coroner says it's more than one perpetrator, I should (b1) construct a model in which the coroner is pressured (or fired and redealt) and (b2) penalize the probability of that model because (hopefully) most coroners aren't pressured.

Replies from: MichaelVassar
comment by MichaelVassar · 2009-12-15T10:05:56.969Z · LW(p) · GW(p)

I'm not sure how much hope fits into the Bayesian analysis. My impression is that doing things like pressuring coroners is routine in the US and probably in Italy as well. Of course, pressuring coroners is a special case of "doing things like pressuring coroners" and thus unlikely a-priori, but its not very unlikely a-priori and once the possibility is raised it doesn't call for much penalty.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T16:25:41.860Z · LW(p) · GW(p)

The significant factor though is not that the coroner was fired and replaced by someone who would report multiple perpetrators. The significant factor is that the original, unprompted, unbiased, objective analysis was that it was a single perpetrator.

Replies from: pete22
comment by pete22 · 2009-12-15T18:01:22.383Z · LW(p) · GW(p)

Anna, I'd be curious to see the link on this when you get a chance.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T18:08:18.563Z · LW(p) · GW(p)

If you type "Mignini fired coroner" into Google, a list of articles comes up. There were too many from which to choose.

Additionally, a great specific, scientific explanation and analysis on the LCN DNA gathering and testing can be found at ScienceSpheres by Mark Waterbury. He starts the blog that way. He has a PhD in materials science.

Replies from: pete22
comment by pete22 · 2009-12-15T19:36:58.206Z · LW(p) · GW(p)

I tried a Google search -- I get a few mentions of Mignini firing his coroner, but they either don't mention a reason or they say it was punishment for leaks to the press. None seem to be from impartial sources, i.e. one is from that truejustice site, another is an article in the Stranger (seattle weekly) by a friend of Amanda's ...the closest thing to a real news site was a Vanity Fair article, and like the others it doesn't mention the first coroner saying there was one assailant.

This is the problem I mentioned in another comment -- all of our info is second- or third-hand. I'm surprised at how comfortable people are citing this stuff. If this was a comparably public case in the US, there's a good chance the entire reports from both the old and new coroner would be on the Smoking Gun and we could be linking to them directly...

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T21:25:32.660Z · LW(p) · GW(p)

It was part of the trial, however, which is why people cite it.

Replies from: pete22
comment by pete22 · 2009-12-16T00:20:54.724Z · LW(p) · GW(p)

One thing to remember is that Mignini fired the coroner doing autopsy investigation when that person said it was the injuries of a single perpetrator. He then hired someone who said it was more than one perpetrator. If you would like, I can find a link to back it up. So the original report said one person caused the injuries.

Again, can you give us your source for this? I'm not doubting you, I just want to get an idea of where it comes from.

Replies from: AnnaGilmour, AnnaGilmour, AnnaGilmour
comment by AnnaGilmour · 2009-12-16T01:03:36.583Z · LW(p) · GW(p)

The following is from a recap of the defense's arguments on closing day. The recap was written by Kelly Brodbeck who was summarizing Ghirga's arguments. I think he got the rundown from a person present at the trial. This is the first thing I can cite. Will continue to look for more.

"He talked about how Mignini stated that the position and condition of Meredith showed that there was more than one person involved in the murder, but when the coroner Dr. Lali said that the body did not show that more than one person was involved, Mignini fired him and replaced him with someone who agreed with his assertions. He said “I wonder why he was really fired??” "

comment by AnnaGilmour · 2009-12-16T01:19:38.865Z · LW(p) · GW(p)

The lack of DNA evidence of a additional perpetrators corroborates the single suspect coroner's result.

comment by AnnaGilmour · 2009-12-16T00:56:21.990Z · LW(p) · GW(p)

No problem... I think even Mignini doesn't dispute it. But I'll seek it out.

comment by komponisto · 2009-12-15T02:37:50.282Z · LW(p) · GW(p)

The various evidence at the crime scene itself of a clean up and/or staged break-in, things like the bra being cut off or the body being moved

A bizarre or unexpected condition of the crime scene is not the explanandum here; Meredith's death is. One person is entirely sufficient to have killed Meredith, and the DNA evidence establishes with virtual certainty that Guede had the kind of contact with her necessary to accomplish this. Unless the evidence suggesting someone else was involved is of comparable power to the DNA evidence against Guede (something on the order of 30 bits), then (and this is the part people have trouble understanding) even paying attention to it at all is automatically hypothesis-privileging.

(EDIT: Eliezer corrects below. What I actually wanted to argue here was that, given the certainty of Guede's involvement, the lack of connection between him and Knox or Sollecito is strong evidence against their involvement -- probably enough on its own to outweigh the comparatively weak evidence against them provided by the alleged indications of multiple attackers at the crime scene.)

Yes, we might be curious about the unusual mechanics of the crime scene given only one person, but unless they are so strange that assuming someone else's guilt of murder (when we already have a suspect) would constitute a reasonable explanation for them, we have to regard the whole question as a distraction.

Replies from: Eliezer_Yudkowsky, pete22
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-15T04:34:37.716Z · LW(p) · GW(p)

Unless the evidence suggesting someone else was involved is of comparable power to the DNA evidence against Guede

Doesn't follow. You can have a lot of evidence for one true statement and then less evidence for another true statement.

Replies from: komponisto
comment by komponisto · 2009-12-15T04:43:23.302Z · LW(p) · GW(p)

Not sure I understand the objection. The point is that the evidence is extremely weak by comparison; not strong enough to justify any attention.

Replies from: Eliezer_Yudkowsky
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-15T17:53:29.962Z · LW(p) · GW(p)

Whether evidence is strong enough to justify attention is an absolute threshold. There is no "extremely weak by comparison". There is just "extremely weak".

Replies from: AnnaGilmour, komponisto
comment by AnnaGilmour · 2009-12-16T00:04:03.107Z · LW(p) · GW(p)

It is extremely weak on its own, and its weakness is compounded and confirmed by the strength of evidence of someone else. The reason for this is that the strong evidence sets up a perameter, a reference point of what is possible for evidence left behind. It puts lines on the thermeter by which to read the murcury. This is because there is also no evidence of collusion, so the physical evidence has to carry most of the weight, if not all. Otherwise, the prosecution's case operates via a tautology.

comment by komponisto · 2009-12-15T20:58:31.925Z · LW(p) · GW(p)

Huh? Attention isn't binary, off-or-on; like evidence itself, it's a quantifiable commodity. The stronger the evidence, the more attention. Right?

Replies from: Cyan
comment by Cyan · 2009-12-15T21:23:31.157Z · LW(p) · GW(p)

There will be some threshold of evidence below which a hypothesis ought to receive strictly zero attention. You could probably even formalize this in terms of bounded rationality.

Replies from: komponisto
comment by komponisto · 2009-12-15T21:36:54.354Z · LW(p) · GW(p)

Right, but I don't need to claim that the anti-Knox evidence is below that threshold. Unless, that is, we're talking about extremely imperfect less-than-Bayesian human minds, who can't intuitively perceive the difference in weight that a perfect Bayesian would assign to 30-bit evidence vs. 10-bit evidence.

comment by pete22 · 2009-12-15T04:47:03.278Z · LW(p) · GW(p)

You're right, this is the part I have trouble understanding. Partly because I have trouble separating the facts of this particular case from the theoretical point you're making. So if you'll humor me for a second: let's say you're the chief of police somewhere, and one of your detectives comes back from a murder scene and tells you "we've arrested a prime suspect and we've got very strong evidence against him, including an ironclad DNA match that ties him to the murder. but we don't think he acted alone, because of X, so we want to keep looking for another suspect."

It sounds like for almost any X, your response would be "Don't waste your time. Case closed. Your hypothesis that there was another killer is unnecessary to explain the victim's death." Is that correct? What kind of X would suffice for you to let your detectives keep investigating?

Replies from: komponisto
comment by komponisto · 2009-12-15T04:54:23.607Z · LW(p) · GW(p)

What kind of X would suffice for you to let your detectives keep investigating?

Two examples that come to mind immediately:

-Similarly incriminating DNA from someone else in addition to the prime suspect.

-Information acquired from the prime suspect himself that points to accomplices.

Replies from: pete22, pete22, pete22, pete22
comment by pete22 · 2009-12-15T05:02:29.373Z · LW(p) · GW(p)

That's setting the bar pretty high. What about witnesses who claim to have seen two men running from the scene, or heard multiple voices at the time of the murder?

Replies from: komponisto
comment by komponisto · 2009-12-15T05:13:49.443Z · LW(p) · GW(p)

Maybe. But remember that reality is consistent: If two people were at the scene committing the crime, why would there be vastly more evidence of one than the other?

Once you have the suspect, you can interrogate him to find out who he knows.

comment by pete22 · 2009-12-15T05:11:01.942Z · LW(p) · GW(p)

Come to think of it, why would a further (unknown) DNA sample even be enough? You've got an explanation for the crime. Surely there are far more likely priors than a double murder that would explain a second DNA sample, right? "Similarly incriminating" might not really be possible; much of what made the first sample so incriminating is that it matched a guy who you already had reason to suspect. Or did you mean that an unknown DNA sample would not suffice, only one that matched another suspect?

Replies from: komponisto
comment by komponisto · 2009-12-15T05:19:00.197Z · LW(p) · GW(p)

If the victim's body and surroundings contains DNA from two different individuals, that would suggest multiple attackers.

Replies from: pete22
comment by pete22 · 2009-12-15T20:01:08.661Z · LW(p) · GW(p)

OK, fair enough. I think I understand your standard better now. But let's go back to the actual case. Here's a quote from that truejustice site's summary of the Micheli report:

2) Judge Micheli explains that blood evidence proves that Meredith was wearing her bra when she was killed. Nor is it just the blood on her bra which demonstrates this. It’s also where the blood isn’t on her body. He says that Meredith was wearing her bra normally when she laid in the position in which she died, and she was still wearing it for quite some time after she was dead. Her bra strap marks and the position of her shoulder are imprinted in the pool of blood in that position. Meredith’s shoulder also shows the signs that she lay in that position for quite some time.

He asks the question: Who came back, cut off Meredith’s bra and moved her body some time later? It wasn’t Rudy Guede. He went home, cleaned himself up and went out on the town with his friends. Judge Micheli reasons in his report that it could only have been done by someone who knew about Meredith’s death and had an interest in arranging the scene in Meredith’s room. Seemingly who else but Amanda Knox?

She was apparently the only person in Perugia that night who could gain entry to the cottage. And the clasp which was cut with a knife when Meredith’s bra was removed was found on November 2nd when Meredith’s body was moved by the investigators. It was right under the pillow which was placed under Meredith when she was moved by someone from the position in which she died. On that clasp and its inch of fabric is the DNA of Raffaele Sollecito and Amanda Knox. Micheli reasons in his report that Raffaele and Amanda seemed to have returned to the cottage some time after Meredith was dead, cut off her bra, moved her body, and staged the scene in Meredith’s room.

At what point exactly do you part ways with Judge Micheli in that chain of reasoning? To me, his reasoning starts to sound stretched around the middle of the second paragraph. But it sounds like you might have a problem with this logic from the very beginning ...? Are you saying the evidence that the body had been moved is just not worth paying attention to?

Replies from: komponisto
comment by komponisto · 2009-12-15T22:18:44.446Z · LW(p) · GW(p)

Are you saying the evidence that the body had been moved is just not worth paying attention to?

If, starting from the premise of Guede's involvement, there are reasons to infer the involvement of someone else, then that sort of thing may very well be worth paying attention to. If the trail through Guede goes utterly cold, however, there comes a point where you just have to declare that Guede's actions + there's-something-we're-missing-about-that-other-"evidence" is a more parsimonious explanation of the data than Guede's actions + someone-like-Amanda-Knox-is-guilty.

In this situation, we should suspect that, if we bothered to investigate further, we would find that we were missing something. And sure enough, by golly, that's what often seems to happen.

Replies from: pete22
comment by pete22 · 2009-12-16T03:55:17.726Z · LW(p) · GW(p)

OK, but why do you keep saying "if"? The judge is making an argument on your terms. He is trying not to privilege the hypothesis. He is starting from the premise of Guede's involvement, and he does find a reason to infer the involvement of someone else. He does not conclude that the trail goes utterly cold, but instead that it leads convincingly to Raffaele and Amanda.

Now, you may disagree with this argument, but I still haven't heard the substance of your disagreement. All you've done is gainsay it.

Don't get me wrong -- I think your original post was a very good explanation of some huge conceptual problems in the way the case against K&S has come together. If I came in believing they were guilty, you would have raised massive doubts in my mind. And that's no small accomplishment on your part. But it doesn't follow that no case against them remains. In order to convince me, or anyone else who's around the average of 35%, that we should lower our odds to your 1-10% range, I think you have to address the facts more directly. It's not enough to say "there comes a point when you just have to declare..." or that certain DNA evidence "doesn't count."

If you were a defense attorney and we were jurors, then you're right, you'd have your acquittal. But it's not a juror's job to distinguish between a 1% and a 35% probability of guilt. To make that case, I don't think you can just point out weaknesses here and there in the prosecution's argument -- you need to lay out the strongest version of the prosecution's case, even if you have to put it together for them, and then show step-by-step why it doesn't lead to a probability higher than 1-10%.

I don't blame you for not doing that, because as I've been saying, the primary sources aren't available to do it -- at least not in objective, quality English translations. I'm just not sure how you can get to such low odds without taking a more granular approach. You've suggested that the correct prior is the (very low) odds of someone like Amanda committing homicide, and others have suggested that the correct prior is the (very high) odds of a convicted defendant in a modern legal system being guilty -- but these are two ends of a spectrum, not binary alternatives. Finding the correct point on that spectrum is equivalent to assessing the strength of the prosecution's case.

Replies from: komponisto
comment by komponisto · 2009-12-16T19:31:12.111Z · LW(p) · GW(p)

He is starting from the premise of Guede's involvement

No he isn't! He's starting from the premise that some investigator found the condition of Meredith's clothing and bloodstains to be unusual given the hypothesis of only one killer. As far as I can tell, he has failed to update properly on the lack of connection between Guede and anyone else who might be a suspect -- not to mention the lack of other evidence (e.g. DNA) that would indicate two or more killers.

In order to convince me, or anyone else who's around the average of 35%, that we should lower our odds to your 1-10% range, I think you have to address the facts more directly.

I'm starting to suspect that we may just have a disagreement about how strong the anti-Knox evidence is. Yes, I agree it isn't literally zero. But that's not the point. The point is that it is utterly dwarfed by the other evidence. Exactly how strong of a dwarfing is this? Well, that's what seems to be the point of contention. I claim the net evidence of Knox's guilt yields a probability of no more than 0.1; you're uncomfortable going below 0.35. The only way to resolve this would be to do some sort of rigorous calculation of the inferential power of clothing-mechanics-analysis evidence -- something which I think would take us too far away from our main topics here.

I suppose I can console myself with the fact that it's good news for Amanda and Raffaele (and bad news for the prosecution) if what are probably the most intelligent and sophisticated discussions of their case on the whole Internet consist of vociferous arguments about whether the probability of their guilt should be 0.35, 0.1, or even lower.

comment by pete22 · 2009-12-15T05:10:23.628Z · LW(p) · GW(p)

That's setting the bar pretty high. What about witnesses who claim to have seen two men running from the scene, or heard multiple voices at the time of the murder?

Replies from: Questor
comment by Questor · 2009-12-16T02:16:55.446Z · LW(p) · GW(p)

those would be the witnesses that appeared months later and whose testimony is doubtful. The running feet and scream women's story cannot be true... a reenactment later showed them to be impossible and they were actually not sure if it was Halloween the night before when there would have been a lot more rowdy students around... And the eyewitness was also discredited.

comment by pete22 · 2009-12-15T05:09:24.128Z · LW(p) · GW(p)

Come to think of it, why would a further (unknown) DNA sample even be enough? You've got an explanation for the crime. Surely there are far more likely priors than a double murder that would explain a second DNA sample, right? "Similarly incriminating" might not really be possible; much of what made the first sample so incriminating is that it matched a guy who you already had reason to suspect. Or did you mean that an unknown DNA sample would not suffice, only one that matched another suspect?

comment by AnnaGilmour · 2009-12-15T23:57:50.172Z · LW(p) · GW(p)

I don't believe there was a staged break-in, but even if there was, how does one logically go from "staged break-in" to Amanda staging it? I detect a logical gap.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-16T00:58:49.886Z · LW(p) · GW(p)

I am new to this site. Can someone elucidate for me why the statement above might have been seen as a minus? Just curious. I was asking for the logical link between the condition of the room and Amanda. One hasn't been provided, not even by the prosecution.

Replies from: pataz1
comment by pataz1 · 2009-12-16T23:24:09.803Z · LW(p) · GW(p)

Guede took off after the murder; his shoeprints in blood are found just outside the door, and in the kitchen leading to the entry door. He was seen a short time later in a club. The judge's rationale in writing in Guede's case was that Guede had no reason to come back and 'clean' anything or to stage a break-in.

There is half a bloody footprint found on the bathmat in the bathroom in the victim's blood, and no similar prints leading up to it, nor is there a similar print in the bedroom, though the blood was pretty smeared. This is what caused the police to do a luminol test.

The people who claim 100% guede did it, stop looking, can't really provide a clear sequence of events that cover the other evidence. Even this blogger looks only at the murder scene, and claims that since there isn't anything else in the room, stop looking.

If the footprint in on the bathroom mat is Guede's, why would he have taken his shoes off? Why would he have cleaned the other footprints? Why would he clean his footprints, but not the shoeprints leading out the door?

Luminol also revealed other prints (and according to my amateur look, lots of smearing) outside of knox's and the victim's door.

The dna of the victim & knox was found in the bedroom that had the purported break-in. The argument is this puts knox in this bedroom after the murder, but that's not a part of any of her stories. And its hard to accept the argument that knox's DNA is in such abundance such that it would be found mixed with the victims in the other bedroom, and at the same time put forth the contradictory argument that the lack of knox's DNA in the victim's room proves her innocent.

Others have made the argument that the height of the bedroom window, combine with the glass only partially broken, would have made it a highly improbable and dangerous option for someone to reach in and open the window that way. It was a single pane of glass apparently that only the bottom 1/3 was out; someone reaching in, it is argued, risked the rest of the glass crashing down on them guillotine style.

I see the primary argument put forth by the blogger here similar to the "No DNA" cry from the FOA; break it down into bits then attack a single part. Looking at anything like that, you can rationally justify just about anything.

Don't get me wrong- I recognize there are valid issues with the DNA found on the knife. The UK has established some procedures for acceptable LCN DNA testing; from all public reports the italian lab didn't follow these. A geneticist legal adviser in Australia wrote essentially an intro to LCN DNA testing sheet, which supports the questioning of the LCN DNA test; essentially if procedures similar to what the UK has outlined aren't followed, then how appropriate is it to rely on the LCN DNA test?

I also think that a dichotomy pervades these arguments; complete innocence, or every single one of them is so guilty they all had their hand on the knife the whole time. There are a number of scenarios of complicity that put Sollecito or Knox at the scene. The ruling of the jury in Italy essentially states that they believe that Knox and Sollecito are complicit in the crime.

Pat

comment by brazil84 · 2009-12-13T10:57:19.016Z · LW(p) · GW(p)

And by the way, if one takes your approach of starting from the crime scene and working backwards you must immediately confront the apparent staging of a break-in at the victim's residence. Which, if I recall correctly, was what initially made the Italian authorities suspicious of Amanda Knox.

Replies from: kodos96
comment by kodos96 · 2009-12-14T18:01:26.710Z · LW(p) · GW(p)

What exactly do you think makes it "apparently staged"? All the evidence I'm aware of is that it looked like a burglary cause it was a burglary.

Replies from: brazil84
comment by brazil84 · 2009-12-14T23:03:32.802Z · LW(p) · GW(p)

To avoid any confusion, can you tell me what you mean by "burglary"? Sorry to be pedantic, but the term apparently means different things to different people. To me, it means breaking into a structure for the purposes of committing a serious crime.

Replies from: BlackHumor, Blueberry
comment by BlackHumor · 2011-07-25T14:42:08.933Z · LW(p) · GW(p)

A murder is a serious crime. Guede clearly had to break into the house to commit the murder, so he also committed a burglary by your definition.

Which would mean there's no evidence that the burglary was staged, because that would mean that in addition to the burglary that Guede committed, ANOTHER burglary must have been staged by someone else. Which would usually be instantly eliminated by Occam's Razor unless there's a significant amount of evidence of two separate burglaries.

Replies from: brazil84
comment by brazil84 · 2011-07-30T02:17:45.029Z · LW(p) · GW(p)

My memory of the case has faded a bit, but as I recall there was evidence suggesting a staged burglary as opposed to a bona fide burglary. Also, Guede needn't have burgled the residence, he may have been invited in by someone who lived there.

comment by Blueberry · 2009-12-14T23:10:08.236Z · LW(p) · GW(p)

You forgot "in a dwelling during the nighttime." ;)

Replies from: brazil84
comment by brazil84 · 2009-12-14T23:32:34.489Z · LW(p) · GW(p)

Lol . . . . yes, that's the traditional formulation.

comment by Psychohistorian · 2009-12-13T06:15:25.736Z · LW(p) · GW(p)

Your point about privileging the hypothesis, and the fact that we feel a need to explain away weird facts in order to believe Knox's innocence, is excellent, though it gets rather buried in a very long post.

As far as the probability estimates go, I expect that many people (like me) did two things: erred on the side of underconfidence, and used numbers as conveying a general feeling. Particularly since it's a criminal case, it doesn't take much to disagree with a conviction. If I'd put the odds of Knox's guilt at .95, I'd say she'd been wrongly convicted, as 5% is extremely reasonable doubt - think that if that were our normal standard, we could have hundreds of thousands of totally innocent people imprisoned. So if people are somewhat like me, they probably just picked a low number to show "not guilty" and left it at that.

Of course, this is largely your point: given the evidence, there's really no reason those numbers should too much higher than they are for a random inhabitant of the city, so our willingness to compromise is itself a flaw, though, in this context, a flaw without adverse effect, as we'd still acquit.

Replies from: MendelSchmiedekamp
comment by MendelSchmiedekamp · 2009-12-13T06:37:33.591Z · LW(p) · GW(p)

there's really no reason those numbers should too much higher than they are for a random inhabitant of the city

Actually simply being in the local social network of the victim should increase the probability of involvement by a significant amount. This would of course be based on population, murder rates, and so on. And likely would also depend on estimates of criminology models for the crime in question.

comment by wedrifid · 2013-04-04T09:05:35.205Z · LW(p) · GW(p)

I have heard that the acquittal of Amanda Knox has been overturned. The sources I have found have mentioned the possibility that Knox could be extradited from the US back to Italy and don't rule that out as a possibility. I am hoping someone with an interest in the Knox case (Komponisto) or someone familiar with US laws could tell me whether that is a possibility.

This is relevant to me since simply labeling Italy as a corrupt state that I wouldn't ever visit costs very little (I have no particular reason to visit Italy). However if Knox is (or even could be) extradited from the USA then that is a problem with the legal system of the United States of America, not just of Italy. The USA is a place I may consider returning to so isn't so easily written off. The prospect of extradition means visiting a country carries all the risks of flaws in that country's legal system as well as all flaws in any country with which it has extradition treaties (subject to whatever filtering the details of those treaties entail).

I am also interested in whether the criticism of the wikipedia coverage is accurate. Wikipedia is a source that I frequently rely on for information. Anything which should increase or decrease the amount of trust I place in wikipedia as a source is useful to me.

Replies from: TimS, V_V, Kevin
comment by TimS · 2013-04-04T14:39:47.267Z · LW(p) · GW(p)

Briefly, the Italians would have to request extradition. If they did, the US would hold a hearing to determine if there was sufficient evidence to extradite. The standard at that hearing is roughly "Is P(guilty) > .25 ?"

Here is a news / opinion article that suggests the Italians are unlikely to ask for extradition, and the standard for extradition probably could not be met. It sounds basically right.

comment by V_V · 2014-02-03T00:35:25.954Z · LW(p) · GW(p)

This is relevant to me since simply labeling Italy as a corrupt state that I wouldn't ever visit costs very little (I have no particular reason to visit Italy). However if Knox is (or even could be) extradited from the USA then that is a problem with the legal system of the United States of America, not just of Italy. The USA is a place I may consider returning to so isn't so easily written off. The prospect of extradition means visiting a country carries all the risks of flaws in that country's legal system as well as all flaws in any country with which it has extradition treaties (subject to whatever filtering the details of those treaties entail).

Isn't that a bit of an overreaction?

I mean, no matter how bad this miscarriage of justice seems to be, the probability of being wrongly convicted of murder while visiting Italy is low, certainly much lower than the probability of being hit by a car.
But being extradited to Italy while visiting the US for a wrong conviction of murder, even if you have never visited Italy before? Probably less likely than being hit by a meteoroid.

Replies from: wedrifid
comment by wedrifid · 2014-02-03T05:50:15.636Z · LW(p) · GW(p)

Isn't that a bit of an overreaction?

I decline to go to Italy based on this and the other research it prompted. The nature of a power structure I am exposing myself to has significance to me even when I am relatively confident in my ability to keep myself self safe. For the same reason I would be unlikely to make a tourist visit a counter-factual USA which still kept all black people enslaved. I'm white so am unlikely to be enslaved but I would still hold what I see in contempt.

the probability of being wrongly convicted of murder while visiting Italy is low, certainly much lower than the probability of being hit by a car.

The information gained about the culture of Italy by the acceptance of ongoing public corruption is not limited to making predictions specific to whether I personally will be falsely convicted of murder.

Replies from: V_V
comment by V_V · 2014-02-03T11:10:33.664Z · LW(p) · GW(p)

So you are not going to visit Italy, and possibly the US, as a form of political protest?

Replies from: wedrifid
comment by wedrifid · 2014-02-03T15:37:30.611Z · LW(p) · GW(p)

So you are not going to visit Italy, and possibly the US, as a form of political protest?

That is not what I said. (I am departing this conversation.)

comment by Kevin · 2013-04-04T10:00:20.656Z · LW(p) · GW(p)

It's a possibility, I think, but it would be a very political issue if it happened, and I would expect the US Department of State to intervene to prevent it.

comment by [deleted] · 2011-06-16T10:04:42.478Z · LW(p) · GW(p)

This post is a year and a half old now, but I think this is still worth saying:

"But come on," says a voice in your head. "Does this really sound like the behavior of an innocent person?"

You have to shut that voice out. Ruthlessly. Because it has no way of knowing. That voice is designed to assess the motivations of members of an ancestral hunter-gather band. At best, it may have the ability to distinguish the correct murderer from between 2 and 100 possibilities -- 6 or 7 bits of inferential power on the absolute best of days. That may have worked in hunter-gatherer times, before more-closely-causally-linked physical evidence could hope to be evaluated. (Or maybe not -- but at least it got the genes passed on.)

This type of thing has no place on Less Wrong. You're telling us to ignore an intuition—not just to be skeptical of it, but to ignore it—because of what is, at best, an educated guess about how we evolved. If this intuition really is unreliable, then it ought to be possible to conduct some sort of experiment showing that it's unreliable. Until we see such an experiment, the best way to proceed is not by ignoring these intuitions, but by mere skepticism.

Replies from: komponisto
comment by komponisto · 2011-06-16T11:03:27.913Z · LW(p) · GW(p)

This type of thing has no place on Less Wrong. You're telling us to ignore an intuition—not just to be skeptical of it, but to ignore it—because of what is, at best, an educated guess about how we evolved.

This is not correct. I'm not telling you to ignore it; I'm telling you that it's worth no more than a few bits of evidence -- few enough to be swamped into unnoticeability by the other data in this context. And, as far as I know, the idea that we evolved in small bands has more than enough scientific support to be taken as a given.

"This type of thing has no place on Less Wrong" is far too harsh, even if you disagree. (It reminds me of "entirely wrong".) Do you have any important disagreement with me about the relative strengths of the evidence under discussion here?

Replies from: None
comment by [deleted] · 2011-06-16T11:53:57.595Z · LW(p) · GW(p)

This is not correct. I'm not telling you to ignore it; I'm telling you that it's worth no more than a few bits of evidence -- few enough to be swamped into unnoticeability by the other data in this context.

Well, would you agree that the phrase "shut that voice out, ruthlessly" could plausibly be interpreted as meaning "ignore that intuition entirely"? That was how I first interpreted it. Perhaps your post should be rephrased, so it's more clear that "shut that voice out, ruthlessly" actually means "recognize that that intuition is contradicted and outweighed by the other evidence".

If that is what you meant, then I agree with this part of your assessment.

"This type of thing has no place on Less Wrong" is far too harsh, even if you disagree.

Well, I do believe that we should not advise people to ignore their intuitions outright, unless we have a very strong argument for doing so. Naturally, this is irrelevant if you are not advising people to ignore their intuitions outright.

Replies from: MarkusRamikin, komponisto
comment by MarkusRamikin · 2011-06-16T13:32:13.122Z · LW(p) · GW(p)

Part of it appears to be Komponisto's style: the post is peppered with things like "completely", "utterly" "nothing", "ruthlessly", "gigantic".

However, I think "shut that voice out, ruthlessly" may be pretty good advice at least at some point in the thinking/decision process. Because even after you've taken everything (including that voice) into account, and concluded that the true answer is different than it "feels", and the intuition you feel is the result of an identified bias, your right answer might still "feel" wrong. The bias will keep injecting doubt, and it takes effort to shake it off. It's hard to get a heuristic to admit it when it's leading you astray. ;)

comment by komponisto · 2011-06-16T13:27:01.517Z · LW(p) · GW(p)

Well, would you agree that the phrase "shut that voice out, ruthlessly" could plausibly be interpreted as meaning "ignore that intuition entirely"?

Tabooing "ignore", I do not think "that intuition constitutes literally zero Bayesian evidence of guilt" is a reasonable interpretation of my phrase. "Your analysis of this case should be for all practical purposes the same as it would be if you didn't have that intuition" is more accurate (where "practical purposes" include things like deciding whether to regard Knox and Sollecito as "innocent" or "guilty", and how strong a level of rhetoric to permit oneself in expressing one's conclusion).

I think it is clear that this post is not about how to distinguish between the kind of extremely small differences in confidence levels that would be entailed by correctly factoring that intuition into one's calculation. Remember that the entire context here is a catastrophic failure of epistemic rationality -- with horrible consequences -- that resulted from people paying too much attention to these types of intuitions. They would have done much better to literally ignore it entirely. (If it actually raises the probability of guilt from 0.001 to 0.002, it would have been better for the police or jurors to have ignored it entirely and estimated 0.001 than to have taken it into account and estimated 0.99, as they effectively did, or 0.5+, as many others have done.)

comment by imgleader · 2010-03-06T15:46:44.274Z · LW(p) · GW(p)

I have a strong preference for the pragmatism of Occam's razor. If William of Occam had been the Knox case prosecutor it would have never come to trial. When supporting negative cultural stereotypes (i.e. promiscuity of American college girls) becomes more important than a rational outcome results like the Knox verdict arise as the judge overlooks evidence to punish the stereotype instead of the defendant.

comment by SforSingularity · 2009-12-27T20:05:16.161Z · LW(p) · GW(p)

I had heard about the case casually on the news a few months ago. It was obvious to me that Amanda Knox was innocent. My probability estimate of guilt was around 1%. This makes me one of the few people in reasonably good agreement with Eli's conclusion.

I know almost nothing of the facts of the case.

I only saw a photo of Amanda Knox's face. Girls with cute smiles like that don't brutally murder people. I was horrified to see that among 300 posts on Less Wrong, only two mentioned this, and it was to urge people to ignore the photos. Are they all too PC or something? Have they never read Eckman, or at least Gladwell? Perhaps Less Wrong commenters are distrustful of their instincts to the point of throwing out the baby with the bathwater.

http://www.amandadefensefund.org/Family_Photos.html

Perhaps it is confusing to people that the actual killer is probably a scary looking black guy with a sunken brow. Obviously most scary looking black guys with sunken brows never kill anyone. So that guy's appearance is only very weak evidence of his guilt. But wholesome-looking apple-cheeked college girls don't brutally murder people ever, pretty much. So that is strong evidence of her innocence.

Replies from: Eliezer_Yudkowsky, Alicorn, Jack, komponisto
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-27T20:27:31.377Z · LW(p) · GW(p)

Girls with cute smiles like that don't brutally murder people.

[citation needed]

Replies from: gwern
comment by gwern · 2009-12-27T20:37:34.916Z · LW(p) · GW(p)

Here's a correlation between ugliness and crime:

(30 seconds on Google.)

Replies from: Bo102010
comment by Bo102010 · 2009-12-27T22:44:33.926Z · LW(p) · GW(p)

Although "unattractive individuals commit more crime in comparison to average-looking ones, and very attractive individuals commit less crime in comparison to those who are average-looking" is evidence for SforSingularity's claim, his comment is absurd enough to be taken as satire.

Replies from: gwern
comment by gwern · 2009-12-28T00:53:24.482Z · LW(p) · GW(p)

It's clearly absurd to say that pretty girls never murder people. But allowing for the normal hyperbole and inexactitude of conversational English, I don't think that's what SforSingularity means, rather, 'pretty girls are one of the demographic least likely to be responsible for a brutal murder'.

This isn't too unreasonable.

  • First off, the number of murders so ascribable are small: females make up half the population and if we limit pretty to the top 5% or so (a reasonable guess at % for 'pretty enough that a guy will actively note and think "pretty!"'), we're already down to less than 2.5% of the population.
  • Second, women in general commit far fewer violent crimes than men. http://www.ncjrs.gov/html/ojjdp/jjbul2002_10_1/page4.html mentions that for juveniles, at one point, the male:female ratio was 22:1. Let's be conservative and put the young adult ratio at 5:1; now we're down to 0.4%.
  • Third, attractiveness is correlated with IQ, and IQ is well-known to correlate with lower crime rates. (see Wikipedia for a few links; IIRC, WP understates the case but I can't be fashed to dig up the stronger correlations). Let's cut another 10% off the rate, down to 0.36%.
  • Fourthly, attractiveness correlates to higher socioeconomic status through multiple mechanisms, which cuts down violent crime even further. (I don't think I need to adduce any citations for that!)

And so on. I've missed many factors (eg. maybe happier & less stressed people are more attractive, and that too is correlated to less propensity for murder; maybe pretty women have fewer violence-inducing mental diseases and substance abuse habits; etc.). But I've already knocked their murder rate way down. I suspect it has much further to go in a true reckoning.

Does his comment still look satirical to you?

Replies from: DanArmak, Douglas_Knight, Bo102010
comment by DanArmak · 2009-12-28T12:33:06.540Z · LW(p) · GW(p)

we limit pretty to the top 5% or so (a reasonable guess at % for 'pretty enough that a guy will actively note and think "pretty!"')

Interesting. When I read "pretty", I thought of a binary division (make guys judge "pretty or not") and I thought it would yield at least 30-40% as pretty. (Possibly much more, but I've a high degree of certainty that at least that much.)

Granted that your test is different than mine, what leads you to your 5% estimate, which looks low to me even with your test?

Replies from: Jack, gwern
comment by Jack · 2009-12-28T12:42:21.812Z · LW(p) · GW(p)

30-40% seems reasonable for Knox's age group (early twenties). Something closer to 5-10% seems reasonable for the entire female population. Keep in mind pretty people are almost certainly more visible than the non-pretty (especially if you have high socio-economic status).

Replies from: gwern, DanArmak
comment by gwern · 2010-01-01T23:20:43.493Z · LW(p) · GW(p)

I think 30-40% is unrealistic: something like 20-30% of females in that age group are overweight or obese, leaving 70-80% in an attractive weight bracket; are we really going to call half of those 'pretty'?

It may just be my media-biased high standards, but I don't think I'd call half of all thin young women that.

comment by DanArmak · 2009-12-28T12:56:36.081Z · LW(p) · GW(p)

Right... I was a fool to miss that. You're perfectly right of course.

Which leads us to the question of what "natural category" to put Knox in. Should it be "a pretty woman out of all women" or "a pretty young woman out of all young women"? Or lots of other options, of course. (We use some category the moment we compare her to women and not to all humans.)

But I'm sure this has been discussed, I haven't read all of this subthread...

comment by gwern · 2009-12-28T14:12:03.387Z · LW(p) · GW(p)

Here's one exercise: take your highschool yearbook, open one of the dense pages (with dozens of pics on it), and let your eye drift along the columns with no particular intent (this is hard); how many of the girls will actually catch your attention for being attractive and not for having, say, bizarre & outdated hairstyles? For me, it was less than 1 in 10. (One plain forgets about the bottom 50% and between that and 90% is the 'unoffensive' range.) Considering that my highschool was private and that selection effects were already operating, I have to revise the estimate further down; ~5% seemed good & is a nice round number.

Replies from: Technologos
comment by Technologos · 2009-12-28T15:47:49.351Z · LW(p) · GW(p)

For what it's worth, I remember a study on Stanford undergrads with what was essentially speed dating; men suggested their interest in a second date with ~90% of the women they met, and simultaneously their top criterion for that choice was attractiveness. Even granting that they had loose definitions caused by the study, I suspect that under Dan's metric (binary choice) a reasonably large minority might be tagged "pretty."

I also didn't get the impression from the photos on the website that anybody in the Knox case was pretty in the sense that you mean it--I think of your criterion as defining "remarkably pretty" rather than "pretty, if I had to choose," and I'd say you're probably right on <5% being remarkably pretty.

comment by Douglas_Knight · 2009-12-28T09:22:41.782Z · LW(p) · GW(p)

First off, the number of murders so ascribable are small: females make up half the population and if we limit pretty to the top 5%..., we're already down to less than 2.5% of the population.

That's like saying very few murders are committed by people named Amanda. That's OK, if you're very careful, but you have to, at least, weigh it against the very few murders by people named Rudy. 2-4 are OK, though.

Replies from: gwern
comment by gwern · 2013-04-03T18:00:51.055Z · LW(p) · GW(p)

Reference class tennis. Being an attractive female with a (formerly) well-off family is far more important a reference class than being named Amanda; and the corresponding reference class for Rudy would be being an unattractive man who is a poor African immigrant.

Replies from: Douglas_Knight
comment by Douglas_Knight · 2013-04-03T23:44:24.192Z · LW(p) · GW(p)

Reread your comment. What is the point of your your first bullet point that pretty girls are rare? That tells you nothing, just as the fact that Amandas are rare tells you nothing. Points 2-4 about the relative propensity to murder are relevant. But I'm explicitly talking about point 1 in isolation.

Replies from: gwern
comment by gwern · 2013-04-03T23:53:42.267Z · LW(p) · GW(p)

What is the point of your your first bullet point that pretty girls are rare? That tells you nothing, just as the fact that Amandas are rare tells you nothing.

Yes, it does. If there is any sort of inverse quasi-linear relationship between prettiness and propensity to murder, as one would expect, we would expect the reduction in murder rates compared to the average to be the largest at the extremes - that is, for rarely pretty girls we will expect rarely large effects.

Replies from: Douglas_Knight
comment by Douglas_Knight · 2013-04-04T00:18:20.607Z · LW(p) · GW(p)

That's not how you used it in your post. Seriously, just read your post. What do these numbers mean?

Replies from: gwern
comment by gwern · 2013-04-04T01:37:40.192Z · LW(p) · GW(p)

Seriously, just read your post.

I rather think I did, since I wrote it.

What do these numbers mean?

It means that we're talking about an extreme part of the population.

Replies from: ESRogs
comment by ESRogs · 2013-04-04T03:12:22.044Z · LW(p) · GW(p)

My own reading of the bullet points in the post is something like this:

1) Group X is a small fraction of the population.

2) Reason A why group X is disproportionately unlikely to commit murder.

3) Reason B why group X is disproportionately unlikely to commit murder.

4) Reason C why group X is disproportionately unlikely to commit murder.

In the great-grandparent comment above you list an additional reason why pretty girls would be disproportionately unlikely to commit murder, but that wasn't clear at least to me from the original post. So, I agree with Douglas_Knight that bullet point 1 seems to serve a different purpose from points 2 through 4.

comment by Bo102010 · 2009-12-28T01:14:46.027Z · LW(p) · GW(p)

I think the "My probability estimate of guilt was around 1%" bit is probably pretty spot on (for the reasons you state), and not absurd.

I think the "I only saw a photo of Amanda Knox's face. Girls with cute smiles like that don't brutally murder people" and "Perhaps it is confusing to people that the actual killer is probably a scary looking black guy with a sunken brow" bits are absurd-enough-to-be-satire.

comment by Alicorn · 2009-12-27T20:26:31.062Z · LW(p) · GW(p)

Via what mechanism does wholesome appearance and apple-cheekedness correlate with a disinclination to commit murder? For example, does a murderous disposition drain the blood from one's face? Or does having a cute smile prevent people from treating the person in such a way as to engender a murderous disposition from without? I wouldn't be exactly astonished to find a real, strong correlation between looking creepy and being dangerous. But I'd like to know how it works.

Replies from: SforSingularity
comment by SforSingularity · 2010-01-01T14:28:44.425Z · LW(p) · GW(p)

Think about it in evolutionary terms. Roughly speaking, taking the action of attempting to kill someone is risky. An attractive female body is pretty much a guaranteed win for the genes concerned, so it's pointless taking risks. [Note: I just made this up, it might be wrong, but definitely look for an evo-psych explanation]

This explanation also accounts for the lower violent crime rate amongst women, since women are, from a gene's point of view, a low risk strategy, whereas violence is a risky business: you might win, but then again, you might die.

It would also predict, other things equal, lower crime rates amongst physically attractive men.

comment by Jack · 2009-12-29T09:03:34.865Z · LW(p) · GW(p)

One of the comments about the photos was mine I believe. I tried to avoid the photos of both Knox and Kercher (though I failed spectacularly). The fact that Knox is pretty and has a cute smile is worth updating on, perhaps. But for me it would be better to be told those facts rather than figure them out by staring at pictures. Millions of years of evolution have made attractive girls my age more bias inducing than just about anything else in my life. For the lonely I imagine the effect is considerably more dramatic. Surely we don't think the men who wrote Knox letters telling her how beautiful they thought she was are seeing things clearly and objectively.

And everyone is programmed to have their protection instincts kick in on the sight of a young, baby- like face (this is why the facial expression of fear resembles the face of a baby).

Replies from: RonnyRaygun
comment by RonnyRaygun · 2010-01-10T21:02:49.703Z · LW(p) · GW(p)

Hello, everyone, my first post, and while I'm not sure it will be seen as entirely rational, here it is anyway :)

I don't know if attractive girls of Amanda Knox's age are more bias inducing. I would tend to think that cute faces do make people feel a certain protective, nurturing instinct. I also think, however, that SforSingularity has a point. I haven't seen any evidence to back it up, but I believe it is rare for "cute" girls to commit violent murder without severe provocation. That's not to say it doesn't happen.

From personal observation, it seems that people who look agressive are more likely to be agressive. Would this be due to the balance of testosterone / oestrogen in the womb, throughout childhood and adolescence, and into adulthood? It would be interesting to find out if studies have been done to prove or disprove this theory. Also, I certainly believe that the above assertions appear to be true in the animal kingdom. Agressive looking animals, almost without exception tend to be more agressive predators. We, both as individuals and as a species, are animals so I see no reason why the same shouldn't apply to us.

Finally, I recently read a study concerning the domestication of dogs. Dogs are known to have evolved from wolves (they can still interbreed very sucessfully) and the hypothesis was that humans selected the most docile wolves and bred them, as they would make better companions and would be easier to train.

To test this, a study was carried out on Russian Silver Foxes. For the last fifty years the most docile foxes have been selectively bred. The current generation is now incredibly docile, and actively seeks out human companionship, but more importantly, they look cute (i.e. they bring out a protective, nurturing instinct in their carers), and show little agression towards people or other animals.

Finally, I don't think any of the above has any bearing on the guilt of Amanda Knox. I am still absolutely amazed that a jury could have convicted her and Sollecito guilty based on the evidence provided.

Replies from: mattnewport, Jack, DanArmak
comment by mattnewport · 2010-01-10T21:23:18.537Z · LW(p) · GW(p)

From personal observation, it seems that people who look agressive are more likely to be agressive. Would this be due to the balance of testosterone / oestrogen in the womb, throughout childhood and adolescence, and into adulthood? It would be interesting to find out if studies have been done to prove or disprove this theory.

I don't know of any studies specifically on aggression but this recent study found evidence that people are able to make significantly better than chance personality judgements based on a single photograph.

Replies from: ideclarecrockerrules
comment by ideclarecrockerrules · 2010-01-10T21:29:46.243Z · LW(p) · GW(p)

Signaling may play a significant role in this.

Replies from: orthonormal
comment by orthonormal · 2010-01-16T03:43:54.622Z · LW(p) · GW(p)

As may microexpressions and other things of which we're not often consciously aware. This doesn't go to the level of a single photograph, but the (badly-named) truth wizards can "observe a videotape for a few seconds and amazingly they can describe eight details about the person on the tape."

We communicate more than we think.

Replies from: lispalien, komponisto
comment by lispalien · 2010-03-25T06:22:23.077Z · LW(p) · GW(p)

I followed this link, and found the blog of one of the "truth wizards" from the study. She writes about the Amanda Knox case. It seems to entirely focus on Amanda Knox.

Replies from: komponisto
comment by komponisto · 2010-03-25T17:44:06.787Z · LW(p) · GW(p)

This has been mentioned before; I'll reiterate my reaction in more detail here.

First of all, there is very little "Truth Wizard" analysis of Amanda Knox on that blog (whatever one thinks about the strength of such evidence in the first place). There are several posts about the case, but in only one of them does the author actually attempt to apply her own "lie-detecting" skills to Knox. (In particular, the most recent post on the case just consists of the author's commentary on someone else's argument that Knox is a sociopath; contrary to orthonormal, there is no claim by the author that she herself has detected sociopathy.)

The one post where the author does analyze Knox concerns her statement at Guede's trial, of which only audio (not video) is available. (Of Knox's videotaped testimony at her own trial, the author says: "...without hearing the questions asked of Knox, it is impossible to identify if she is lying." -- emphasis added.) Thus, there is no data about facial expression, which is apparently an important component of the author's technique. Hence confidence in this analysis must be presumably be lowered from what it would be if the author were working from a video recording.

But in any case, the reasoning in that post is awful. To the extent the author is skilled in detecting lies, she is obviously not particularly skilled in explaining how she arrives at her conclusions. Here is an example:

Does this make any sense? She couldn't remember because she was tired? It was the middle of the night? Does anyone believe this is a good reason for a lack of all memory? When Amanda is telling us this, a year has passed from the crime, so why doesn't she elaborate more in this statement? Why isn't she setting the record straight for the judge here and now?

The author seems to be expecting Amanda's memory of an incident to improve over time. Now, I'm not an expert on memory, but this is directly contrary to my understanding of how it works. In fact, (to invoke my own memory here) I distinctly recall Eliezer mentioning once that memories are re-created each time we remember something. If this is true, it implies that memories -- even if they become more vivid! -- would become less entangled with reality over time, not more; which is anyway what you would expect from....physics.

Here is another, well, "red flag", concerning Knox's account of being hit on the back of the head by a police officer:

So, what ended up happening was.... the fact that I had been pressured so much, and I was....(sigh), I was hit in the back of the head by one of the police officers...who said she was trying to make me...help me remember the truth.

She was pressured so much that she was hit on the back of the head? Does that make sense? Why does she change "make me" which is a strong statement to "help me", which is much softer? I find this odd. If someone is hitting me on the back of the head, they aren't "helping me" do anything. They are making me forcefully and brutally react. Why aren't her emotional memories matching her story?

The author completely misses the obvious interpretation (in the absence of prejudice), which is that the phrase "make me" reflected Amanda's emotional interpretation of the situation, but that she corrected it to "help me" in order to more accurately recount what the officer(s) actually said!

This kind of shoddy reasoning is, I regret to say, characteristic of the author's (rather limited) discussion of the case. Whatever truth-detecting skills she may possess, I don't think her posts have provided us with very much useful information at all.

Finally, I will point out that the author (who by the way links to True Justice but not to any pro-Knox site) claims not to have made an incorrect judgement in 5 years...and yet now lists this case among her "successes"! Obviously, that's more than a bit problematic. (It should be noted that not only is the appeals process ongoing, but the conviction only intensified the controversy, if anything.)

comment by komponisto · 2010-01-16T15:58:07.696Z · LW(p) · GW(p)

Link (1:44) for those interested in trying the video experiment on themselves in the present context.

For a much more extended sample, see here.

comment by Jack · 2010-01-10T21:44:39.754Z · LW(p) · GW(p)

Welcome! Feel free to introduce yourself here.

comment by DanArmak · 2010-01-10T22:24:53.526Z · LW(p) · GW(p)

my first post, and while I'm not sure it will be seen as entirely rational [....]

And then:

I haven't seen any evidence to back it up, but I believe [doesn't matter what exactly....]

Belief without evidence - that's irrationality, right there. You may be misunderstanding the meaning of "evidence" - especially as that word is used in this community.

Replies from: Jack
comment by Jack · 2010-01-10T22:32:46.741Z · LW(p) · GW(p)

I assume he means studies or 'scientific' evidence (as if there were some other kind).

Replies from: DanArmak
comment by DanArmak · 2010-01-10T22:39:22.647Z · LW(p) · GW(p)

The other kind is rational (Bayesian) evidence. That's what most people here mean by unqualified "evidence", I think.

Replies from: Jack
comment by Jack · 2010-01-10T23:02:36.064Z · LW(p) · GW(p)

Scientific evidence is Bayesian evidence, no? I was just implying that I didn't think there was a special category of evidence gathering delimited as 'science'.

Replies from: Technologos
comment by Technologos · 2010-01-10T23:14:37.709Z · LW(p) · GW(p)

Best I can tell, Science is just a particularly strong form (/subset) of Bayesian evidence. Since it attempts (when done well) to control for many potentially confounding factors and isolate true likelihoods, we can have more confidence in the strength of the evidence thus obtained than we could from general observations.

Replies from: Jack
comment by Jack · 2010-01-10T23:28:57.274Z · LW(p) · GW(p)

Yeah, though a lot of science is just building localized, domain specific ontologies (here's what kinds of fish there are, here's what kind of stars there are etc.) and I'm not sure this kind of scientific knowledge is much better than observations you or I make routinely. Also, some evidence gathering is every bit as powerful as science (or more so) and yet is rarely counted as a science ( advanced sports statistics or marketing studies for example).

comment by komponisto · 2009-12-29T07:11:09.588Z · LW(p) · GW(p)

My probability estimate of guilt was around 1%. This makes me one of the few people in reasonably good agreement with Eli's conclusion.

As far as I am aware, all we know about EY's number is that it is bounded from above by 15%.

Since the average estimate was 35% (and that was before this post, after reading which some people said they updated downward, and no one said they updated upward), it's fair to say a lot of people were in reasonably good agreement with EY's conclusion.

Perhaps Less Wrong commenters are distrustful of their instincts to the point of throwing out the baby with the bathwater.

I don't know whether SfS's comment is to be taken as attempted satire or not, but I did wonder if a sort of "Spock bias" might result in reluctance to update on the sort of evidence presented here or here. As it turned out, that didn't seem to be so much of an issue here on LW (for all that character assassination of Amanda played a role in the larger public's perception). By far the biggest obstacle to arriving at probability estimates close to mine was that old chestnut: trusting in the fundamental sanity of one's fellow humans. (The jury must have known something we didn't, and surely Judge Micheli knew what he was doing...)

Replies from: Eliezer_Yudkowsky
comment by Eliezer Yudkowsky (Eliezer_Yudkowsky) · 2009-12-29T08:32:45.486Z · LW(p) · GW(p)

The idea was that anything over 15% was wildly unreasonable.

comment by LauraABJ · 2009-12-13T21:41:26.900Z · LW(p) · GW(p)

Ok- many people have already pointed out that the prior should be probability of having committed murder if you live in the same house as someone murdered. Now, I would like to add that the psychological evidence shouldn't be completely and utterly discounted.

1) Knox knew Guede and Kercher, the murderer and the murdered, and is thus not random. This alone is reason for suspicion (though certainly not indictment).

2) Knox wrote a story about the drugging and rape of a young woman. Anyone have statistics on how many murderers have written such rape- fantasies or how many fantasy writers are violent offenders?

3) Knox really wasn't able to give a consistent story about her whereabouts. (I discount this a lot more now knowing her testimony was given under duress, but can't dismiss it entirely.)

Now, this doesn't add up to all that much, but certainly more than the p = 0.001 you are claiming. I think the odds are higher that she talked with Guede i n passing before he raped and murdered kercher than that she was there when it happened (due to absence of evidence and failure of guede to implicate her).

Replies from: Blueberry
comment by Blueberry · 2009-12-13T21:45:08.341Z · LW(p) · GW(p)

Knox wrote a story about the drugging and rape of a young woman.

Did she really? Link/cite please? Is the story available anywhere?

I realize it may affect probability calculations, but it just doesn't seem fair to use someone's fiction against him.

Replies from: Psychohistorian, LauraABJ
comment by Psychohistorian · 2009-12-23T19:37:42.993Z · LW(p) · GW(p)

It's doubly unfair in the context of an assignment. I wrote an incredibly gory horror story when I was in elementary school; I would probably have been sent to see the principle if it had happened today. It had nothing to do with me being a violent person and everything to do with me thinking that it was how one wrote an effective horror story.

More generally, deviant writing and fantasies tend to be way, way more common than you'd think (simply since people do a decent job of concealing them), so just because someone writes something unusual or has unusual fantasies, that does not strongly suggest that they actually engage in such behaviour.

As a simple example, people who run over hookers and take their money in Grand Theft Auto are probably much more likely to do so in real life than those who do not. However, the number of them who actually do so is so small that even this significant increase in probability is not very useful. Even if they are a hundred times as likely to do this, going from .0001% to .01% is not as big of an increase as, "They're a hundred times more likely!" sounds.

comment by LauraABJ · 2009-12-13T21:56:29.052Z · LW(p) · GW(p)

I can't find it- though the excerpts given in the NYTimes do sound more like a soap-opera than a rape-fantasy.

Replies from: Kevin
comment by Kevin · 2009-12-14T04:29:51.767Z · LW(p) · GW(p)

No link handy, but it was for a class assignment and Knox's story was by far not the most violent out of the stories written by her peers.

Replies from: wedrifid
comment by wedrifid · 2009-12-14T05:42:51.186Z · LW(p) · GW(p)

No link handy, but it was for a class assignment and Knox's story was by far not the most violent out of the stories written by her peers.

"I can't do the assignment miss, because I don't want to be imprisoned for murder!" I'm going to have children just so I can recommend that excuse to them.

comment by Quest4Truth · 2009-12-23T21:15:56.687Z · LW(p) · GW(p)

komponisto - you are a genius. For months I have felt that Amanda and Rafaelle were clearly innocent, but I could not properly rationalize or verbalize my feelings. How could the entire internet be wrong? How could the jury be unanimously wrong? Now I understand. Thank you and I love your blog. As others have noted, this site is the only place I have found cordial and intelligent debate among the opposing viewpoints.

comment by AnnaGilmour · 2009-12-16T01:25:33.214Z · LW(p) · GW(p)

I find the evidence of the conspicuousness of the prosecution's investigation and case for Amanda and Raffaele's guilt much more suspicious and compelling than the evidence left by Amanda and Raffaele. What would the probability/certainty numbers be on that?

comment by mariz · 2009-12-14T19:05:02.820Z · LW(p) · GW(p)

Posts like this are the reason I read this blog. Great job.

comment by Kevin · 2009-12-14T08:20:44.940Z · LW(p) · GW(p)

I think it's important to establish that it is likely that Knox and Sollecito could be lying about large portions of the night's events. Certainly they have told some lies. They were even legally allowed to lie as witnesses in Italian court. They may very well have been at the apartment before or even during the murder. It still does not make them guilty of murder.

comment by Bo102010 · 2009-12-14T01:55:06.711Z · LW(p) · GW(p)

This was a brilliant post. You deserve buckets of karma.

I didn't read the first part of the series until later - I wish I could have participated.

Replies from: komponisto
comment by komponisto · 2009-12-14T07:59:57.572Z · LW(p) · GW(p)

Upvoted for making me feel good, after I was bummed out for having overstated my case. :-)

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T00:31:40.896Z · LW(p) · GW(p)

I don't think you overstated your case. The point was that there is an almost absolute disparity of evidence between Guede's guilt and Amanda or Raffaele's guilt.

comment by ChristianKl · 2009-12-13T17:36:17.791Z · LW(p) · GW(p)

There something like a TV bias. In TV shows there often physical evidence at a crime scene that's needed for the narrative of the story. In real life there often isn't a lot of physical evidence.

That bias is strong enough to let some prospectors ask jurors about how much they watched shows like CSI to select jurors that don't believe that there has to be physical evidence.

To me it seems you are a victim of the bias that real life crime scenes look like TV crime scenes.

Replies from: wnoise, Jack, komponisto
comment by wnoise · 2009-12-13T17:51:12.322Z · LW(p) · GW(p)

They did find lots of crime-scene evidence in this case -- pointing toward Guede.

comment by Jack · 2009-12-14T07:50:51.249Z · LW(p) · GW(p)

Given the number of convicted people who were later exonerated by DNA evidence it isn't obvious to me that juries expecting physical evidence is a bad thing. One thing entailed by komponisto's discussion of the emphasis humans put social and mental facts is that the pre-CSI judicial system assigned too much weight to such facts and likely imprisoned innocent people. And it turns out they really did imprison innocent people. So maybe it is the judicial system's bias, not komponisto's...

Replies from: Unknowns
comment by Unknowns · 2009-12-14T07:53:15.577Z · LW(p) · GW(p)

Even so, the number of people exonerated by later DNA evidence is nowhere near 90%.

Replies from: Jack
comment by Jack · 2009-12-14T07:59:40.051Z · LW(p) · GW(p)

What is special about 90%?

Replies from: Unknowns
comment by Unknowns · 2009-12-14T08:01:48.483Z · LW(p) · GW(p)

We're discussing a claim that someone convicted of murder has a 90-99% chance of being innocent. That could be true, but not merely because they used evidence other than DNA evidence.

Replies from: Jack
comment by Jack · 2009-12-14T08:23:55.983Z · LW(p) · GW(p)

Oh. Obviously P(Guilty | untested DNA evidence) doesn't equal P(Guilty | no solid physical evidence of any kind & no motive & extensive physical evidence implicating someone else)... and I actually think .1 is too low a probability of Knox's guilt. I was just pointing out that the mere fact that CSI has lead to some jurors expecting physical evidence does not mean that those jurors are more biased than those content to convict without physical evidence. If we have an evolved bias to over-emphasize social and behavioral evidence then it is perfectly possible that watching CSI compensates for a bias rather than creates one.

comment by komponisto · 2009-12-14T07:24:07.558Z · LW(p) · GW(p)

In general (with a very few idiosyncratic exceptions), I despise crime shows, and have never seen an episode of CSI in my life.

comment by brazil84 · 2009-12-13T10:44:50.441Z · LW(p) · GW(p)

For what it's worth, I would have been much more inclined to agree with you before I became a practicing attorney. Having practiced law for many years, I've had many opportunities to assess a case based on hearing one (sometimes 2) sides of the story and then to learn a lot more about the case through the discovery process and then the trial process.

In short, I have a lot of practice in assessing peoples' guilt or innocence and I'm pretty confident that Amanda Knox was involved in the murder of her roommate.

Replies from: Jack
comment by Jack · 2009-12-13T12:00:49.226Z · LW(p) · GW(p)

Can you make explicit your intuitions? What experiences in particular lead you to think this?

Replies from: brazil84
comment by brazil84 · 2009-12-13T12:37:20.207Z · LW(p) · GW(p)

Well I've learned as an attorney that in general when people engage in a big or concerted effort to conceal, destroy, or manipulate evidence it's usually because the evidence is (or is perceived to be) damaging to their interests. Here, it seems pretty clear that Amanda Knox staged a break-in to her residence. Why would she do that if she were not involved in the murder?

At a minimum, she must have known before the police came that her roommate had met with serious misfortune. And how would she have known that if she had not been involved in the murder?

Similarly, it seems pretty clear that Knox attempted to manufacture an alibi by spinning a web of lies. Which is difficult to do nowadays since there are various electronic forms of evidence (cell phone records, internet records, etc.) to catch you up, which appears to be what happened.

I suppose it's possible she did all of this because she was innocent but still afraid the police would put the blame on her. But that doesn't make much sense since she could have easily pointed the finger at the African.

Replies from: Jack
comment by Jack · 2009-12-13T15:31:01.838Z · LW(p) · GW(p)

I'm pretty sure everyone agrees that if it is the case that Knox staged a break-in, knew before the police came that something happened to her roommate or tried to manufacture an alibi by spinning a web of lies then she is likely guilty. And we probably don't need experience as attorneys to tell us that. The question is whether or not the evidence in favor of those things outweighs the absence of physical evidence or any motive, and the fact that female college students don't commit many sexually motivated throat slittings. What evidence for the former exists and how that evidence should be interpreted doesn't appear to be a settled matter. At this point I'm not clear on what was misinformation and what wasn't. But even if a break-in was staged we have no particular evidence tying Knox to the staging. And the so-called "web of lies" is hard to distinguish from the tale of a scared and confused girl abused by police. She must have known something bad had happened to her roommate? This is big news to a lot of us, explain.

Replies from: brazil84, Unknowns
comment by brazil84 · 2009-12-13T15:55:27.238Z · LW(p) · GW(p)

"I'm pretty sure everyone agrees that if it is the case that Knox staged a break-in, knew before the police came that something happened to her roommate or tried to manufacture an alibi by spinning a web of lies then she is likely guilty."

I'm not sure if that's true, since the original poster did not really address the staging issue. There is a lot of evidence one can consider, and each of us can make our own judgment about what evidence is more important and what evidence is less important.

Anyway, let's break things down a bit, since your 3 "ifs" are not logically independent.

  1. Do you agree that if Amanda Knox staged a break-in, then she was probably involved in the murder?

  2. Do you agree that the evidence does in fact suggest that a break-in was staged?

  3. Do you agree that if a break-in was staged, the likely perpetrator (of the staged break-in) was somebody who had lawful access to the residence?

Replies from: Jack
comment by Jack · 2009-12-13T16:37:57.440Z · LW(p) · GW(p)

1, Yes.

  1. Whoever was in there appears to have made some effort to make things look like a burglary (that is the best explanation for the strewn clothes and the fact that nothing was missing). But that doesn't mean the window breaking was staged. I find the argument that the window as inaccessible and that the glass was on top of the clothing unpersuasive. I don't know if forensics got good photos of the glass, how much there was or if we're just relying on the word of the roommate.
  2. If the window breaking was staged then it was likely done by someone with lawful access- that could be Knox, someone with Knox's key, Sallecito, Guede invited up by Kercher, one of Kercher's friends, the landlord etc.
Replies from: McJustice, brazil84
comment by McJustice · 2010-01-03T00:30:38.014Z · LW(p) · GW(p)

I have not seen any evidence for a staged break in in Filomena's bedroom. And none was presented that was believable. A video was shown that appeared to show out of focus bits of glass on a dress... the idea being that the room was ransacked first and then glass fell on top from a staged window break. The problem with the blobs in the video was that they were not glass but polka dots on a an article of clothing as shown by other pictures of the same things. There is only Mignini's claim that it was based on the notion that nobody could have climbed in the window as well as him probably not liking it much since it did not fit his multi-person satanic orgy murder theory. And it is impressive that the alleged stager was so clever they managed to get glass only inside the room along with the rock... and as for nothing missing. Rudy liked to take money, phones, laptops and other things... From the burglaries we know of ( and allegations that he rifled through girls purses at Discos besides hassling the girls as well) he did not seem to take bulky items or valuable items like jewelry that could be fenced. We are not told what he did not take and cannot judge the value or utility of stealing them. He evidently did not find money there but he did later steal Meredith's rent money since his bloody fingerprints are on her purse. He did have money to spend at the disco and to flee to Germany and survive there for 2 weeks and the assumption is that it was Meredith's.

He may have been interrupted by Meredith coming home and after that had little interest in going back to a room he had already searched and did not find any money or items he may have wanted. After getting Meredith's money and raping her body and cleaning up (and he had over 2 or 3 hours to do all this) it is understandable he had less interest in rummaging through the other bedrooms and left to go to the Disco. He apparently stank according to the people who say him there so evidently did not go to his own flat first to shower.

comment by brazil84 · 2009-12-13T21:40:33.041Z · LW(p) · GW(p)

I'm a little confused by your answer to number 2. It sounds like you basically agree that somebody tried to stage a break-in. No?

Replies from: Jack
comment by Jack · 2009-12-14T01:23:54.172Z · LW(p) · GW(p)

Someone staged a burglary. It isn't necessarily the case that the broken window is part of a staged burglary rather then a way some intruder actually got in. Perhaps the murderer came in through the broken window but knew the victim and thought that making it look like a burglary would send the police in another direction.

Replies from: brazil84, kodos96
comment by brazil84 · 2009-12-14T02:31:03.630Z · LW(p) · GW(p)

Well that's an important point. As others and I have mentioned, there is a small universe of people who would have had much incentive to stage a burglary. And that universe includes Amanda Knox and her boyfriend.

(Further, without knowing anything more, Kercher's roommate(s) would be the strongest suspects of such a staging. Because (1) only a roommate wouldn't have to worry about another resident showing up and discovering him or her; and (2) a roommate would have the strongest incentive to try to point the police somewhere else. For example, if a casual acquaintance broke in through the window and murdered Kercher, what would that person have to gain by staging a burglary? In effect, they've already engaged in a burglary anyway.)

Anyway, if somebody from that limited universe of suspects is hiding something and can't account for his whereabouts at the time of the murder, it's pretty likely that they were involved in the staging/murder.

Replies from: AnnaGilmour, Jack
comment by AnnaGilmour · 2009-12-15T16:32:42.456Z · LW(p) · GW(p)

The idea of a staged burglary came from Mignini and was unsubstantiated. Since then, it has been debunked. He claimed it was staged due to two shards of glass on clothing. Those shards close up were revealed to be polka dots.

Replies from: brazil84, AnnaGilmour
comment by brazil84 · 2009-12-15T17:50:44.225Z · LW(p) · GW(p)

Well do you agree that one of the bedrooms had clothing and such strewn around it while the owner of the room testified that the room had been left orderly?

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T17:57:01.918Z · LW(p) · GW(p)

Logically, items strewn around the room does not implicate Amanda. The connection of the messy room and Amanda was invented by the prosecution. It could be explained by various means, namely, during the struggle with the perpetrator and Meredith, or more likely, the perpetrator looking for something to steal.

Replies from: brazil84
comment by brazil84 · 2009-12-15T18:10:28.650Z · LW(p) · GW(p)

I'm not sure what your point is. I thought you were claiming that there was essentially no evidence which reasonably supports the hypothesis that somebody staged a burglary or break-in.

Now it seems you admit that there is such evidence but believe it could be explained away.

Replies from: AnnaGilmour, wedrifid
comment by AnnaGilmour · 2009-12-15T18:17:51.487Z · LW(p) · GW(p)

I don't think there is evidence of a staged break-in. I think there is evidence of a break-in.

Replies from: brazil84
comment by brazil84 · 2009-12-15T18:20:03.763Z · LW(p) · GW(p)

Well do you agree that the room's occupant testified that there had been valuable items in plain view, none of which were taken?

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T18:38:59.211Z · LW(p) · GW(p)

I think he was looking for money. It was the 1st of the month and rent was due. Meredith had dated casually a guy downstairs and Rudy had hung out there. Also, I think it is likely he didn't expect to find anyone home and was interrupted when Meredith came home early, for an early night. I don't think he was planning to take objects, though might have if uninterrupted.

Replies from: AnnaGilmour, brazil84
comment by AnnaGilmour · 2009-12-15T18:42:02.654Z · LW(p) · GW(p)

Also, Meredith's $300 was missing, and somehow he had the money to ride a train the next day to Germany.

comment by brazil84 · 2009-12-15T18:51:14.493Z · LW(p) · GW(p)

I don't understand what point you are trying to make. There is a difference between saying that evidence can be explained away and saying that the evidence does not exist.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T19:00:42.518Z · LW(p) · GW(p)

To have evidence of a break-in is different than having evidence of a staged break-in. Since there is evidence of a break-in, but not any that would say it was staged, there is evidence of an invented idea of a staged break-in. I'm not saying that a lack of evidence of something being staged means it wasn't. But going the rules in the post, there is nothing that would indicate it was staged from the evidence itself. That part is fallacious. It exists in the mind of Mignini, not in the evidence.

Does that clarify what I mean?

Replies from: AnnaGilmour, brazil84
comment by AnnaGilmour · 2009-12-15T19:05:27.006Z · LW(p) · GW(p)

I'm sayinig he made up the staged part, since the evidence for a staging (rather than a break-in) did not exist in the crime scene. He imposed his ideas on the reality before him. He looked for things to support his idea, and those things were shown to be false or unrelated logically to Amanda.

comment by brazil84 · 2009-12-15T19:12:54.664Z · LW(p) · GW(p)

Not really. For example, the ransacking of a room but the failure to take valuable items in plain view is evidence of a staging. Yes, there are other explanations for this evidence but that does not mean it's not evidence of a staging.

Replies from: AnnaGilmour
comment by AnnaGilmour · 2009-12-15T21:05:31.295Z · LW(p) · GW(p)

In terms of the rules of the post, it takes a leap to get to the idea of a staging. One has to infer it. Amanda's DNA is not on the glass or the objects, anyway, even in the unlikely event that there was a staging.

Replies from: brazil84
comment by brazil84 · 2009-12-16T01:58:59.364Z · LW(p) · GW(p)

"In terms of the rules of the post, it takes a leap to get to the idea of a staging. One has to infer it."

Sorry, but I have no idea what this means. Interpreting evidence is always a matter of inference.

Replies from: AnnaGilmour, wedrifid
comment by AnnaGilmour · 2009-12-16T17:11:06.999Z · LW(p) · GW(p)

"Interpreting evidence is always a matter of inference."

Without physical evidence of something, how do you, except by imagination, come up with an explanation? Logic of the situation, yes. But this forms a tautology in this case. She broke the window and staged a break-in (though there is no physical evidence that suggests this) because... why? Because... someone wants it to look like she did the crime. My point was that komponisto showed how you have to have a reason in the situation itself to suggest it. This theory of the staged break-in is being used as a reason to suspect Amanda. The reason to suspect Amanda of a staged break-in is that more evidence is needed to implicate her in the crime. To say that "if Amanda staged a break-in, it would implicate her" may be true, but it would also be true of anyone. It could equally be true of the other two roommates, for example. The only thing that made Amanda stand out in this regard is that she was there first and that someone read into her behavior as significant.

This is how it seems to me.

Replies from: brazil84
comment by brazil84 · 2009-12-16T17:20:26.147Z · LW(p) · GW(p)

"The reason to suspect Amanda of a staged break-in is that more evidence is needed to implicate her in the crime."

That's one reason. A better reason to suspect Amanda of a staged break-in is to note that there is in fact evidence of a staged break-in and to observe that (1) it's mainly somebody who was closely associated with the victim who would have had a motive to do such a thing; and (2) Knox had a good opportunity to do so.

"only thing that made Amanda stand out in this regard "

stand out compared to whom?

comment by wedrifid · 2009-12-16T02:07:42.187Z · LW(p) · GW(p)

Sorry, but I have no idea what this means.

I find this hard to believe, particularly after the multiple explanations given to you. Even if these multiple explanations that leave open technicalities for exploitation by a reader who does not desire comprehension. I get the impression that you are being disingenuous. If not, please reread the grandparent again assuming the sentence "One has to infer it." was removed.

Replies from: brazil84
comment by brazil84 · 2009-12-16T02:14:56.916Z · LW(p) · GW(p)

"I find this hard to believe, particularly after the multiple explanations given to you."

There's no way to prove it. But let's do this:

Please give me a couple of examples of evidence and (possible) conclusions which "require a leap" as well as a couple of examples of evidence and (possible) conclusions which do NOT "require a leap."

That should make things clearer.

Replies from: wedrifid
comment by wedrifid · 2009-12-16T02:57:56.927Z · LW(p) · GW(p)
  1. The house has been reduced to a pile of charred debris -> There was a fire.
  2. The house has been reduced to a pile of charred debris -> There was arson.

Anna would obviously call 2) a leap but not 1). I am aware that a similar process of inference is involved, differing only by degree and yet I am still able to grasp what Anna is trying to say. That Anna has explained what she is trying to say multiple times helps, as does my IQ. Yet I don't think either of these things are required to get at least some idea of the intended meaning and certainly don't get the impression that you lack the intellectual resources to do so yourself, should you desire. Agreement, of course, is a different matter.

I will make these observations:

  • Evidence of a break in increases p(staged break in).
  • Evidence that the break in was staged increases p(guilt).

One line of reasoning is this:

  • Evidence of a break in increases p(a break in was staged).
  • Evidence that a break in was staged increases p(guilt).
  • There is evidence of a break in.
  • Therefore, the evidence of a break in increases p(guilt).

This does not follow. Evidence of a break in decreases p(guilt). That is precisely why someone would have motive to stage a break in! Anyone who attempted to increase the extent to which the above fallacious reasoning was applied would be doing something I disapproved of strongly.

Replies from: brazil84
comment by brazil84 · 2009-12-16T10:30:13.822Z · LW(p) · GW(p)

"The house has been reduced to a pile of charred debris -> There was a fire. The house has been reduced to a pile of charred debris -> There was arson. "

Well, what if a house has been reduced to a pile of charred debris and traces of some volatile flammable liquid are found there? It seems to me that by Anna's reasoning, it would be a "leap" to say that this is evidence of arson. And yet most reasonable people would agree that this is evidence of arson.

Anyway, I would appreciate it if you would assume I am trying to discuss this in good faith.

"One line of reasoning is this:

Evidence of a break in increases p(a break in was staged). Evidence that a break in was staged increases p(guilt). There is evidence of a break in. Therefore, the evidence of a break in increases p(guilt). "

I'm not sure that anyone is making that argument here. At any rate, I am not.

Replies from: wedrifid
comment by wedrifid · 2009-12-16T10:43:48.868Z · LW(p) · GW(p)

Well, what if a house has been reduced to a pile of charred debris and traces of some volatile flammable liquid are found there? It seems to me that by Anna's reasoning, it would be a "leap" to say that this is evidence of arson.

That would be evidence of arson. Anna's reasoning would not call this a leap. As a reminder, the position of Anna's that you were refuting in this branch of comments is this:

To have evidence of a break-in is different than having evidence of a staged break-in. Since there is evidence of a break-in, but not any that would say it was staged, there is evidence of an invented idea of a staged break-in.

You disagree elsewhere with the premise but here you are arguing against, and misunderstanding (whether motivated or not), the argument.

Replies from: brazil84
comment by brazil84 · 2009-12-16T11:12:14.203Z · LW(p) · GW(p)

"That would be evidence of arson"

Then again I do not understand Anna's distinction. If there is a ransacked room but no valuables are missing, even though those valuables were in plain view, that is evidence of staging. In the same way, a burned house with traces of volatile flammables present is evidence of arson. In either case, it's easy to explain away the evidence in a way which is consistent with some other conclusion. But in either case, the evidence raises the probability of the conclusion.

"As a reminder, the position of Anna's that you were refuting in this branch of comments is this:"

Would you mind pointing me to the post where I attempt to refute this? TIA

Replies from: wedrifid
comment by wedrifid · 2009-12-16T14:46:20.620Z · LW(p) · GW(p)

Would you mind pointing me to the post where I attempt to refute this? TIA

This thing that you did not attempt to refute. Hold that in your mind. Now, consider the thing that you didn't understand. Put the thing that you didn't refute in where the thing you didn't understand was. You can now comment on Anna's point in 'good faith'.

Replies from: brazil84
comment by brazil84 · 2009-12-16T17:05:08.751Z · LW(p) · GW(p)

I have no idea what your point is. Let's do it this way:

Please explain to me the fundamental difference between the following 2 claims :

(1) If there is a ransacked room but no valuables are missing, even though those valuables were in plain view, that is evidence of staging; and

(2) a burned house with traces of volatile flammables present is evidence of arson.

Replies from: wedrifid
comment by wedrifid · 2009-12-16T20:29:40.760Z · LW(p) · GW(p)

Please explain to me the fundamental difference between the following 2 claims

None.

I have no idea what your point is. Let's do it this way:

If you are interested in understanding the point being made then there is more than enough information available to you. I will not engage further.

Replies from: brazil84
comment by brazil84 · 2009-12-16T20:51:00.497Z · LW(p) · GW(p)

"None."

That's completely contradictory to your earlier statements. Before you explicitly said that that the arson example was NOT a leap by Anna's standards.

And yet the staging example IS a "leap" by Anna's standards.

And yet there are no fundamental differences between the two examples, according to you.

"If you are interested in understanding the point "

I am interested in understanding the point. And now the problem has become obvious: Your (apparent) position is self-contradictory.

"I will not engage further."

It's your choice, but I think it would be better for you to just acknowledge the contradiction in your position (actually Anna's position as explained by you) rather than pretend to yourself that I am being disingenous.

Replies from: wedrifid
comment by wedrifid · 2009-12-16T21:27:47.744Z · LW(p) · GW(p)

(actually Anna's position as explained by you)

A good clarification and I'll inject "the part of Anna's position in this branch".

That's completely contradictory to your earlier statements. Before you explicitly said that that the arson example was NOT a leap by Anna's standards.

You are wrong. I distinguish the acceptance of the premise from the validity of the intuitive leap to a particular conclusion.

Your (apparent) position is self-contradictory.

My position is highly specific, self contained, without self contradictions and really not even particularly novel.

I think it would be better for you to just acknowledge the contradiction in your position (actually Anna's position as explained by you) rather than pretend to yourself that I am being disingenous.

My description now would be far less complementary than that.

"I will not engage further."

I hereby lower the confidence I place in my predictions of what I may post in the future. My intuition appears to be founded on an incomplete model of likely responses of others.

Replies from: brazil84
comment by brazil84 · 2009-12-16T22:09:54.884Z · LW(p) · GW(p)

"You are wrong."

Lol, that's nonsense. Here is our exchange:

Sez I: Well, what if a house has been reduced to a pile of charred debris and traces of some volatile flammable liquid are found there? It seems to me that by Anna's reasoning, it would be a "leap" to say that this is evidence of arson.

Sez you: That would be evidence of arson. Anna's reasoning would not call this a leap.

Clearly you were saying that the Arson example is not a leap by Anna's standards.

Next, an earlier exchange between me and Anna:

Sez I: Not really. For example, the ransacking of a room but the failure to take valuable items in plain view is evidence of a staging. Yes, there are other explanations for this evidence but that does not mean it's not evidence of a staging.

Sez Anna: In terms of the rules of the post, it takes a leap to get to the idea of a staging.

So clearly the ransacking example is a "leap" by Anna's standards.

And yet you yourself admitted just a few posts back that fundamentally there is no difference between the 2 situations. Do I need to quote you?

It's comple