Privileging the Hypothesis

John Wilkes Booth: You know you really ought to do something about that stomach.

Zangara: I do everything about the stomach!

Booth: Oh yes?

Zangara: I give up wine. No good! I give up smokes. No good! I quit my work. No good! I move Miami. No good! I TAKE APPENDIX OUT! No good! Nothing no good! Nothing! Nothing! Nothing!

Booth: Have you considered shooting Franklin Roosevelt?

Zangara: You think that help?

Booth: It couldn't hurt...

-- Assassins shows up how privileging hypotheses is done.

Just to confirm:

Another way of explaining the 'locating the hypothesis' concept would be to say: "When answering a question with a large number of possible answers, it takes more work to narrow down the possibilities (generate the reasonable hypotheses) than it does to test those hypotheses for correctness."

Is that right?

I agree that privileging a hypothesis is a common error. I don't agree that it applies in the example used, though.

If you have a tradition thousands of years old saying that a particular spot was the site of Nazareth in 4BC, or of Troy in 1200BC, it isn't irrational to privilege the hypothesis that that spot was indeed the site of Nazareth, or of Troy.

Similarly, when the entire world has used the single-world hypothesis almost exclusively until the recent past, it isn't unfairly privileging it to still consider it a major contender.

You might think this is more like evolution vs. creationism. I don't mean that we should keep teaching creationism in school as an alternative today. But we haven't got as strong an argument for many-worlds as we do for evolution.

Also, AFAIK there's just these 2 competing hypotheses: One-world, many-world. We don't have the 7-worlds hypothesis and the 23-worlds hypothesis and the pi-worlds hypothesis. We could have the countable-worlds hypothesis and the uncountable-worlds hypothesis, but AFAIK we don't even have those. How can you say it's irrational to consider 1 of the only 2 hypotheses available?

I don't know, this "Mortimer Q. Snodgrass" fellow seems pretty suspicious to me. I mean, a weird name like that is probably an alias. And "Ordinary Lane"? At a power of 2 no less? Tell me he plays tennis and I'll be convinced he did it.

I don't know if there's another name for privileging the hypothesis, but it seems closely related to anchoring, in that it involves establishing an unjustifiable "starting point" from which to search.

You are asserting a false duality. Either many-worlds, OR a collapse postulate. You use evidence AGAINST a collapse as evidence FOR many worlds, which is very weak evidence. Here is a third alternative- the wavefunction is not real- merely a mathematical formalism used to calculate probability distributions (this map doesn't have to be the territory). Here is a fourth- collapse is an approximation to a small, non-linear self-coupling in the equation that governs time evolution. Here is a fifth- evolution is governed by both the advanced and retarded Green function solution to the Schroedinger equation, and what appears to be collapse is a sort of beat-resonance between the two. Here is a sixth- there are(non-local) degrees of freedom apart from the wavefunction and 'collapse' occurs because our existing theory is confused about what devices actually measure. I could keep going.

Every one of the above has a huge advantage over many worlds- there is positive evidence to update in their favor. Because they accurately reproduce most of quantum mechanics, all that evidence that we can use to push us to "quantum mechanics is probably right" CAN lead us to any of the above theories.

Many worlds does NOT have Born probabilities, and so IT DOES NOT MAKE PREDICTIONS. No one knows how to use many worlds to do anything at all. So you are doing a very weird sort of Bayesian process- you use Copenhagen or one of the above theories' predictions to update your belief to "quantum mechanics is probably right." Now starting from this new belief, you use other facts to update to "many worlds is probably right." Unfortunately, you didn't notice that in switching to many worlds, all of that evidence that pointed to quantum mechanics is gone.

If you start from an agnostic prior, many world's has no predictions to push you in the direction of "this is the right theory."

I think that "privileging the hypothesis" is an example of special pleading (http://en.wikipedia.org/wiki/Special_pleading) being applied to the selection of a hypothesis, as opposed to the evaluation of the hypothesis.

And the corresponding anti-epistemology is to talk endlessly of "possibility" and how you "can't disprove" an idea

Something to point out to someone who says this is that 'possibility' is not a constraint - EVERYTHING is possible. As far as I know (and correct me if i'm wrong cause that would be a major fuckup), you can't assign a probability of zero to anything. You can't seperate the possible things from the impossible ones, and then focus only on the possible. 'Possible', by itself, applies to everything, so you don't say anything by declaring something 'possible'. It's only when you start talking about degrees of possibility that the word has any meaning.

I tend to think that the Bible and the Koran are sufficient evidence to draw our attention to the Jehovah and Allah hypotheses, respectively. Each is a substantial work of literature, claiming to have been inspired by direct communication from a higher power, and each has millions of adherents claiming that its teachings have made them better people. That isn't absolute proof, of course, but it sounds to me like enough to privilege the hypotheses.

Eliezer, speaking of "privileging the hypothesis," what do you think about the proscription in statistics against "data dredging," or using past data to support post hoc hypotheses suggested by the data? What do you think about the view of descriptive science being inferior to hypothesis-driven science?

Based on your analysis, it would indeed seem that a hypothesis that could be located prior to an experiment might be more probable than a hypothesis that could only be located after an experiment.

Yet is there an over-emphasis placed on the state of mind of the particular experimenter prior to data collection? What if another scientist on the other side of the world had a hypothesis, which our original experimenter only came to after doing a study looking at something else. Can the second scientist say that the study confirms his hypothesis (because he held it in advance), while the first scientist cannot (because he only came to his hypothesis after doing the study)?

What if the post-hoc-hypothesized effect is very strong and related to plausible mechanisms in the field? What if it showed up in lots of previous studies that were looking at other things?

EDIT: Non-Eliezer people are invited to reply to this comment also.

I think this is a great follow up to: http://lesswrong.com/lw/o3/superexponential_conceptspace_and_simple_words/ (scroll to the very end of that post)

ideological organisations like think tanks, political parties and religions do this

"But because of a historical accident, collapse postulates and single-world quantum mechanics are indeed on everyone's lips and in everyone's mind to be thought of"

I think there's more to it than historical accident. After all, it was a historical accident, of sorts, that people believed one could sail directly west from Europe to arrive in Asia, but once a continent was found in between it was no trouble at all to overturn that belief. Historical accident is not the only reason, or necessarily the major reason, that we are still struggling with single-world QM today. I think if we had started with Everett, and someone had later come up with Copenhagen, the latter would gain a nontrivial number of adherents. Note: this should not be taken as justifying Copenhagen in any way. I am merely saying that this particular analysis of the egregious error that is Copenhagen is not complete.

grand total of zero

I have perceived exactly one world all my life. Isn't that evidence that exactly one world exists?

It may be that privileging the hypothesis -- or, more specifically, unjustifiably promoting a hypothesis about the goodness of a particular product or service to people's attention -- is the business end of TV advertising.

In general I agree, and of course Copenhagen is nonsense, but I think you privilege the hypothesis of Many-Worlds over Bohm. You see, Bohm has an explanation for the Born probabilities---they are a stable equilibrium state called, appropriately, "quantum equilibrium". So there are not even any open questions.

And yes, Bohm is non-local, which you could say is a problem... or you could say it explains why quantum mechanics is different from classical mechanics. (Obviously no quantum theory is going to satisfy all our classical intuitions, or it wouldn't be a quantum theory at all!)

It doesn't fit with general relativity, you say? Yes, because none of them do. Quantum gravity doesn't... work, not with our current formalisms. This is the central problem of modern physics (that and dark energy, which most physicists think is related somehow).

Eliezer: privileging the hypothesis is known as the Prosecutor's fallacy. I like your name better though.

I see how this applies to different deities of the same complexity. What about the Maimonidean-type "negative theology" - http://en.wikipedia.org/wiki/Negative_theology#In_the_Jewish_tradition ? Basically this implies a perfectly simple diety "of reference class size 1". It seems harder to say that the hypothesis is arbitrary in this case.

Im just reading Thomas Schelling's Theory of Conflict and one of his key tenets is that providing an identifiable point around which the discussion can be centered will tend to lead the discussion to be centered around that (classical anchoring). However, he brings out that in many cases, having a "line in the sand" brings benefits to all sides by allowing intermediate deals to be struck when only extremes were possible before.

This article, however, clearly demonstrates that having a line in the sand can be just as bad as it can be good, as it is with all of biases. However, I really recommend Schelling hit on "what is good" (in the evolutionary sense) about this phenomenon.

The following formula is difficult to read at a first glance because of the unfortunate line break: (water -> ice cubes + electricity)

I was first trying to parse it as: water "minus" "is greater than" ice cubes...

The wikipedia article for Abductive Reasoning claims this sort of privileging the hypothesis can be seen as an instance of affirming the consequent.

Good post.

I'm not sure that 'privileging the hypothesis' deserves to be called a fallacy, though. It's only a bad idea because of the biases that humans happen to have. It can lead to misconceptions for us primates, but it's not a logical error in itself, is it?

Posthoc hypothesising is only a problem when you're using that hypothesis to analyse the same data that inspired it. Machine learning experts avoid this mistake by backtesting and foreward testing out of sample data.

Analysing unstructured data is useful for generating hypotheses, rather than for testing them to develop a model. Take computational epidemiology:

In contrast with traditional epidemiology, computational epidemiology looks for patterns in unstructured sources of data, such as social media. It can be thought of as the hypothesis-generating antecedent to hypothesis-testing methods such as national surveys and randomized controlled trials.

What do you think of Huw Price's suggestion (http://www.powells.com/biblio/72-9780195117981-0) that if one allows for the possibility of advanced action, it's possible to have paradox-free physics within a single universe, since Bell's theorem only proved the non-existence of non-local hidden variables?

I'd call this "Mistaking the Likelihood for the Posterior".

Poor Mortimer he always gets the blame. :)

Surely being a supervillain (possibly formerly) is worth a lot of evidence against Mortimer, though.

This isn't a fallacy; this is just trusting the information you're given. You've gamed the system to break expectations.

Someone tells me, "Don't touch the stove when it's red; it will burn your hand." That's the hypothesis. I'm assuming it's built on some experience and knowledge. Of course I'm going to privilege this particular hypothesis instead of the many others, like "When the stove is red, you will win the lottery," or "When the stove is red, you can't die." I'm trying to get up to speed on an ongoing situation, and so I'm going to trust that some hypotheses have already been discarded as useless by those who are informing me of the situation.

Someone who spends all day thinking about whether the Trinity exists is probably doing so because his parents raised him in Christianity, and so he is trusting his parents' wisdom, or he was told about Christianity from a missionary, who he trusts. We trust experts. I don't see this as a bad thing.

Speaking of privileging the hypothesis...

http://www.theonion.com/content/video/crime_reporter_finds_way_of

This is essentially an instance of availability bias. Of course, the most interesting case, rather than just a declarative hypothesis elevated among the other inhabitants of the hypothesis space for that particular question, models have other effects that go far beyond merely availability.

This is because our initial model won't just form the first thing we think of when we examine the question, but some of the very structures we use when we formulate the question. Indeed, how we handle our models is easily responsible for the majority of the biases that have been discussed here and at Overcoming Bias.

In the case of the models mentioned in this post about quantum mechanics - we can look at the first quantum mechanics interpretation as having its own version of hypothesis privilege. This means we should downgrade it. Of course we should also do the same with its immediate successor, Many Worlds (although perhaps not as much). After all, it is the interpretations we haven't thought of which are being penalized the most by the effect of privileging the hypothesis.

But to adequately apply this discounting beyond the direct route we need to understand the way which these model affect our thinking. How do these models encourage other models being developed, and how do they blind our cognitive architecture from different avenues?

This becomes even more pronounced when more is at stake than epistemic rationality. Since these two models are also sides (even fairly politely) in cultural and political conflicts, there are further biases that arise, as parts of these ideas become further tied to status, self-esteem, social behaviors, and habits.