Posts

Making Less Wrong Great Again 2016-06-01T04:34:35.320Z · score: -10 (53 votes)
Request for Steelman: Non-correspondence concepts of truth 2015-03-24T03:11:18.651Z · score: 13 (17 votes)
Ethics in a Feedback Loop: A Parable 2014-07-25T16:25:40.799Z · score: 9 (42 votes)

Comments

Comment by peergynt on On the importance of Less Wrong, or another single conversational locus · 2016-11-28T05:19:54.561Z · score: 8 (8 votes) · LW · GW

the tech support doesn't give a fuck, and will cite privacy concerns when you ask them for more direct access to the database

Seriously, who are these tech support people? Clearly this database belongs to the owner of less wrong (whoever that is). As far as I can tell, when moderators ask for data, they ask on behalf of the owners of that data. What is going on here? Has tech support gone rogue ? Why do they then get their contract renewed? Are they taking orders from some secret deep owners of LW that outrank the moderators ?

Comment by peergynt on On the importance of Less Wrong, or another single conversational locus · 2016-11-27T09:02:00.374Z · score: 42 (42 votes) · LW · GW

This is not going to happen unless you deal with the troll

Comment by peergynt on Making Less Wrong Great Again · 2016-06-02T05:23:19.662Z · score: 3 (3 votes) · LW · GW

I don't understand why this comment is downvoted and I want to go on record to say it wasn't me. I appreciate when people tell me why they downvote my posts.

I definitely did expect mixed reactions to the original post. I'll be honest and say that I'm surprised that people keep downvoting it to levels that I associate with malicious trolls, rather than let it stay hidden at -5 which seems appropriate for a failed attempt at humor. But it doesn't really matter, it would take much more than negative reactions to a joke to stop me from making Less Wrong great again :)

Comment by peergynt on Survey: What's the most negative*plausible cryonics-works story that you know? · 2015-12-23T23:05:43.063Z · score: 3 (3 votes) · LW · GW

Hi there, Mac. I'm a Matrix overlord. Can I have my 10 dollars, please?

Comment by peergynt on LINK: An example of the Pink Flamingo, the obvious-yet-overlooked cousin of the Black Swan · 2015-11-05T18:50:20.404Z · score: 3 (3 votes) · LW · GW

Could you specify whether you want answers as percentage probability, probabilities, odds, or expected number of launches? My answer was intended as a percentage

Comment by peergynt on Robert Aumann on Judaism · 2015-08-21T21:30:47.330Z · score: 4 (4 votes) · LW · GW

So there is free money to be had by posing as a rabbi and offering a bet to Robert Aumann?

Comment by peergynt on The Mr. Hyde of Oxytocin · 2015-05-10T17:31:29.109Z · score: 1 (1 votes) · LW · GW

Using OxyContin(tm) for a job interview seems like a distinctly bad idea. Particularly if the employer asks for drug screening.. If you absolutely have to, I suggest sticking with Oxytocin.

Comment by peergynt on Stupid Questions May 2015 · 2015-05-04T14:52:11.604Z · score: 1 (7 votes) · LW · GW

Why do you care about the 'original' meaning of the word?

Let's imagine we are arguing about trees falling in the forest. You are a lumberjack who relies on a piece of fancy expensive equipment that unfortunately tends to break if subjected to accoustic vibrations. You therefore create a map where the word "sound" means accoustic vibrations. This map works well for you and helps you resolve most disguised queries you could be interested in

Then you meet me. i make a living producing cochlear implants. My livelihood depends on making implants that reliably generate the qualia of sound. I therefore have a different map from you, where the word 'sound' means the subjective experience in a person's brain. This works well for the disguised queries that I care about.

If we meet at a cocktail party and you try to convince me that the 'original' meaning of sound is accoustic vibrations, this is not a dispute about the territory. What is happening is that you are arguing the primacy of your map over mine, which is a pure status challenge.

The purpose of categories in this context is to facilitate communication, ie transfer of information about the territory from one mind to another. Agreeing on a definition is sometimes important to avoid confusion over what is being said. However, if there is no such confusion, insisting on one definition over another is a pure monkey status game

Comment by peergynt on Stupid Questions May 2015 · 2015-05-03T04:12:24.954Z · score: 30 (34 votes) · LW · GW

What is the LessWrong-like answer to whether someone born a male but who identifies as female is indeed female?

The Lesswrong-like answer to whether a blue egg containing Palladium is indeed a blegg is "It depends on what your disguised query is".

If the disguised query is which pronoun you should use, I don't see any compelling reason not use the word that the person in question prefers. If you insist on using the pronoun associated with whatever disguised query you associate with sex/gender, this is at best an example of "defecting by accident".

Comment by peergynt on Wikipedia articles from the future · 2014-10-30T17:10:00.182Z · score: 2 (2 votes) · LW · GW

I can see why this would look strange to a German speaker. It was just intended as a joke/reference to the Wikipedia article on the Vienna Circle. I've fixed the grammar

Comment by peergynt on Wikipedia articles from the future · 2014-10-30T04:51:46.072Z · score: 0 (8 votes) · LW · GW

Less Wrong

Less Wrong (German: Weniger Falsch) was an association of philosophers gathered on the internet in 2007, chaired by Eliezer Yudkowsky. Among its members were Yvain, Lukeprog, Michael Vassar, Will Newsome and Gwern. PeerGynt was an eminent student at the time. He was allowed to participate in meetings, but was not a member of Less Wrong.

Members of Less Wrong had a common attitude towards philosophy, consisting of an applied rationalism drawn from Eliezer Yudkowsky, whose Sequences formed the basis for the group's philosophy. Less Wrong's influence on 21st century philosophy was immense, and much later work was in response to the group's thoughts.

The pre-history of Less Wrong began with blog posts on the philosophy of science and epistemology from 2006, promoted by Robin Hanson on Overcoming Bias.

(This is only half joking. If you want the rest of the future history of Less Wrong, it is available at http://en.wikipedia.org/wiki/Vienna_Circle . )

(Edited to fix Google Translate's German grammar)

Comment by peergynt on Rationality Quotes October 2014 · 2014-10-08T23:47:01.194Z · score: 1 (3 votes) · LW · GW

But some fences were created to serve interests that no longer exist: Hadrian's Wall, for one. The fact that someone >centuries ago built a fence to keep the northern barbarians out of Roman Britain does not mean that it presently >serves that purpose. Someone who observed Hadrian's Wall without knowledge of the Roman Empire, and thus the >wall's original purpose, might correctly conclude that it serves no current military purpose to England.

At the risk of generalizing from fictional evidence: This line of reasoning falls apart when it turns out that the true reason for the wall is to keep Ice Zombies out of your kingdom. Chesterton would surely have seen the need be damn sure that the true purpose is to keep the wildlings out, before agreeing to reduce the defense at the wall.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-29T21:15:52.605Z · score: 0 (0 votes) · LW · GW

You don't succeed in avoiding getting mind killed yourself. You switch for no reason towards real life.

Discussing the issue in terms of real life does not itself imply that I've been mindkilled (though it may increase the chance that the discussion ends up being subject to mindkill). If you think I have been mindkilled, please show me a specific instance where I used arguments as soldiers, or where I failed to update in response to a properly made argument.

General ethical consideration suggest that you only inflict pain on other humans if they consent.

That is a totally acceptable ethical view that is fully consistent with my parable. At no stage did I assert "Since we only care about Martians, it is acceptable for them to do anything they want to the Earthlings". Instead, I invited you to have discussion about what actions are ethical and which actions are not ethical. In such a discussion, one of the possible sides you can take is that the Martians should never tickle anyone without consent.

However, the real world implication of this assertion of it is that no man should attempt to interact with women unless they are certain that they are sufficiently high status to avoid seeming creepy.

(Note that I probably shouldn't have used "stinging pain" as an analogy for creepiness and social awkwardness. This was an overcompensation in order to avoid seeming biased in favor of men).

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-29T17:03:28.856Z · score: -1 (1 votes) · LW · GW

Sure. The point I was trying to make is that, while I see females as agents in real life, in this analogy I am discussing the ethics of a choice that is only made by men. The analogy therefore did not require a fully specified model of females as agents.

There are many true things in the world that I chose not to specify in the analogy. For any of those things, if you give me a specific reason why it is relevant to the choice made by the Green Martians, then it certainly should have been part of the analogy. However, there is no law of nature that says "females should always be fully specified as agents in any analogy"

Comment by peergynt on Open thread, July 28 - August 3, 2014 · 2014-07-29T15:33:39.919Z · score: 2 (4 votes) · LW · GW

It is true that some participants in the analogy are "non-player characters". That is because some ethical questions only have implications for the choices of a subset of the agents. It should be permissible to discuss these ethical questions. Doing this properly will require adding information about all stakeholders whenever it is relevant, but it does not necessarily require all stakeholders to be "playable" in the sense that they actively make ethical decisions.

It is also true that the women in my story have a preference on a single axis, and that in real life, they also have preferences on other axes. I did not specify those preferences in the analogy, because I did not see the point in adding complications that do not have relevance to the resolution of the ethical question, which is a choice faced only by Martians.

If you feel that there is an additional axis which has important implications for the ethical choice that the Green Martians are facing, please specify what that axis is and why it is important. This would be an important contribution to the discussion. Otherwise, this comes across as saying "you should have added additional complications that were not relevant, in order to sufficiently signal that women are important ethical agents and not objects".

The fact that women are important ethical agents is so obvious that it is not even worth debating. However, I shouldn't have to signal this at every opportunity as a precondition for taking part in the discussion, especially not when this would require me to add unnecessary information to the story.

As for why the women don't express their preference not to be tickled by green martians, this is simply because I took this preference to be obvious and common knowledge to all participants in the analogy.

Comment by peergynt on Open thread, July 28 - August 3, 2014 · 2014-07-28T21:29:21.641Z · score: 9 (11 votes) · LW · GW

I'm fairly sure this comment was not exactly intended as a compliment, but I can think of worse insults than having my writing put in the same category as Nick Bostrom. As the author of the first of these parables, even I recognize that these two stories differ very significantly in quality

The Blue and Green Martians parable was an attempt to discuss a question of ethics that is important to many members of this community, and which it is almost impossible to discuss elsewhere. The decision to use an analogy was an attempt to minimize mindkill. This did not succeed. However, I am fairly sure that if I had chosen not to use an analogy, the resulting flamewar would have been immense. This probably means that there are certain topics we just can't discuss, which feels distinctly suboptimal, but I'm not sure I have a better solution.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-27T00:51:38.122Z · score: 7 (9 votes) · LW · GW

It's been a day since this discussion peaked, and I've had a chance to think a little bit more about this on a meta-level:

First of all, having a community built around epistemic hygiene is extremely valuable. Discussions about topics that involve mindkill are incredibly unpleasant, and may make it impossible for such a community to be successful. I therefore fully understand people who want to keep these discussions away from Less Wrong, and I won't post again on this topic or any other mindkilling topic.

That said, I think the inability to discuss this rationally and dispassionately is a major problem for society in general, which may contribute to some individuals with abnormal psychology reacting in unpredictable ways. My only view on the object-level question is that low status men get a raw deal, that there is no good solution to the problem, and that PUA is probably very bad ethically. I have natural sympathy for low-status men, but I recognize that I may be biased because I have no experience seeing the situation from a female perspective. The post was an attempt to invite people to help me update my moral beliefs, by hearing from people who do not have those biases. Importantly, this could not have been done on any other website, because they would have been unable to convince me that their moral framework was coherent, that they are being honest about their ethical beliefs, or that they have made a good-faith effort to model low status males as relevant participants in the moral calculus.

There was some really good discussion in this thread, particularly Skeptical Lurker's comment, which may have made me aware of a contradiction in my worldview. I will keep thinking about what updates may be necessary. This is exactly the kind of feedback that I was hoping for - changing your mind is a good thing, and it is only possible if we can gave a genuine discussion as rationalists.

That said, for the Less Wrong community, the cost of these discussions probably outweighs the benefits.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-26T01:44:40.717Z · score: 1 (3 votes) · LW · GW

This is possible. Could someone please explain the important aspects of the PUA worldview that are being misrepresented? Particularly if they are relevant to the ethical question I am interested in? This would certainly help me clear up some confusion.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-26T01:33:56.098Z · score: -1 (1 votes) · LW · GW

Fair point - I should have phrased that differently. I think I intended that both in the weak sense "Our prior on moral statements should never be 0 or 1" and also in the slightly stronger sense "Ethics is difficult, so our priors should have high variance"

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-26T00:53:25.144Z · score: 7 (11 votes) · LW · GW

I want to point out that I, perhaps incorrectly, assumed this thought experiment could be interesting even to the anti-PUA crowd, because it would help them distill their thinking about whether they object to PUA on epistemic grounds ("they have incorrect beliefs about female psychology") or if they object on moral grounds ("they draw incorrect / evil conclusions about the ethical implications of the theory")

From the reactions, it is tempting to conclude that most people object to PUA partially on epistemic grounds. However, it is hard for me to understand why a disagreement about facts would lead to such heated debate in a community based around the Litany of Tarski.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T23:08:24.035Z · score: 5 (7 votes) · LW · GW

Your translation of the analogy takes the postition that the status dichotomy is a thing. The rest follows from that assumption.

No, it takes the position that there exist people who believe status dichotomy is a thing, and then explores some of the consequences if this belief were to be true.

Moreover, status dichotomy is very obviously a lossy compression. For some purposes, this construct will lose so much information as to be useless. For other purposes, the information that is lost by dichotomizing status is not essential, and so it may still be a useful model.

In order to convince me that dichotomous status is not a useful model when what we are interested in is exploring the ethical issues in this post, you would have to show me a situation where considering a continuous or multidimensional status construct is necessary in order to make an essential point with implications for the correct ethical choice. If you are able to do this, you will have contributed a lot to the conversation, and I will have learned something important.

Being a pleasant person to be around is beyond a man's responsibility?

No, what I meant was that a Martian cannot be held morally responsible for whether he is Green or Blue.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T22:10:57.819Z · score: -1 (1 votes) · LW · GW

I am a moral realist, I believe there exists an objective moral standard which is part of the territory. This is the moral standard we are talking about.

Obviously, we are unable to know whether our ethical maps correspond to the ethical territory. We should therefore update our priors about the ethical territory in response to good arguments and thought experiments. Throughout this discussion, I have made several updates to my beliefs.

If we don't believe there is such a thing as an objective ethical standard, if the territory doesn't exist, then I fail to see the point in even discussing ethics.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T21:58:10.175Z · score: 0 (2 votes) · LW · GW

Thank you, this is exactly the kind of discussion I was hoping for. I don't really have anything to add, I agree with essentially everything here. Can we can please keep the discussion at this level?

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T21:44:47.459Z · score: 0 (6 votes) · LW · GW

I am certainly learning from any useful comments that are made, regardless of which position they take. This is not one of those comments. It is also the only comment in the thread which I have downvoted - I am trying to have a discussion about ethics in a hypothetical world, not a flame war.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T21:34:46.339Z · score: 7 (9 votes) · LW · GW

Those are not my views:

First of all, I took no position on the truth value of the premises.

Secondly, I fully recognize that my analogy is a simplified map of a map. It does not accurately represent the full territory.

The question is whether the aspects of the territory that I have glossed over are important for the resolution of the ethical question. If there are any such aspects, please feel free to point them out. I do recognize that some of the aspects that have been pointed out, such as consent, are important. I have upvoted those comments and attempted to explain why I think you can make the argument that the analogy still has some validity.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T20:55:19.453Z · score: 10 (12 votes) · LW · GW

Let me just point out that the post was an attempt to discuss ethics in a hypothetical world where certain PUA claims about human psychology are true. I think this is an important question, and I did not want it to degenerate into a discussion about whether the claims themselves are true.

I tried my best to make the analogy as neutral as possible, by making women the "humans", describing the PUA strategies as having a real harmful effect on women, and generally making their dislike of PUA strategies seem entirely reasonable.

I don't see how the post is tendentious. I don't think the analogy has any obvious ethical solution, and I am genuinely asking people for insight into what the relevant ethics are in this hypothetical world. I don't see how I am leading people to give me validation on my views, because I am not even sure what my views are.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T19:22:11.576Z · score: 4 (6 votes) · LW · GW

OK, I really would prefer that this discussion stays on the abstract level, but in order to avoid confusion, I will provide a translation of the intended metaphors:

Green Martian = Low Status Male

Blue Martian = High Status Male

Earthling = Female

Tickling = Flirting (Including obnoxious strategies such as "negs" and "kino escalation")

The moderately painful sting of the tentacles of the Green Martian = Creepiness, Social Awkwardness, etc

Experimentation on Earthlings (defined in comments) = Sex

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T19:17:49.194Z · score: 1 (7 votes) · LW · GW

OK. Good point. I am going to specify that in this thought experiment, tickling is only effective if there is no explicit consent.

Edit: See definition of tickling here: http://lesswrong.com/lw/klx/ethics_in_a_feedback_loop_a_parable/b5ft?context=1#b5ft

Also, note that this is a thought experiment. The point of this comment is not to make a claim about the truth value of the statement "flirting is only effective if there is no explicit consent", but to explore the ethical consequences of a world in which this is true.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T18:06:55.577Z · score: 4 (6 votes) · LW · GW

I definitely see the humans as agents, whose preferences are morally relevant. In fact, the reason this is even ethically ambiguous in the first place, is that humans have a preference not to be tickled by green martians.

The reason humans come across as passive, is that I am specifically asking about the ethics of an action that is generally conducted by the active Martian to the passive human. It is at least theoretically possible that this question can be resolved without considering any ethical dilemmas that the humans face. This does not mean that the humans are not considered as important moral agents, only that their agency is not something that has any impact on the ethics of a choice made my Martians.

If you can think of a reason why having a full map of the ethical agency of the human is necessary to resolve the ethics of the choice faced by the Martian, I would be very interested in hearing it and will update accordingly.

Comment by peergynt on Ethics in a Feedback Loop: A Parable · 2014-07-25T17:09:50.051Z · score: 4 (8 votes) · LW · GW

In this society, it is generally accepted that tickling is not something that requires consent.

Even more than the Martians want to tickle humans, they want to carry them away to their mothership to experiment on them. Everyone agrees that experimentation on humans requires their consent. Part of the socially accepted foreplay that sometimes leads to humans giving their consent to be experimented on, consists of the martian tickling the human behind the ear.

Comment by peergynt on Why Eat Less Meat? · 2013-07-24T15:37:15.857Z · score: 6 (6 votes) · LW · GW

A source is "Allison, Richard. “Organic chicken production criticised for leaving a larger carbon footprint.” Poultry World. 1 Mar. 2007". This article is behind a paywall. I am pasting a table from the article:

AVERAGE ENVIRONMENTAL IMPACT FROM POULTRY PRODUCTION (% DIFFERENCE TO CONVENTIONAL) Organic Free range

Energy use +33% +25%

Global warming potential (CO2) +46% +20%

Eutrophication potential +75% +28%

Acidification potential +52% +33%

Pesticide use (dose/ha) -92% +12%

Note: This article is in a trade publication and could be biased. It is based on an original report which I could not locate, and which apparently has sparse data. Obviously, more research is needed.

My prior beliefs are not the result of scientific studies, but follow from the following observations:

(1) To reduce global warming, we need to maximize the number of calories produced per unit of CO2 emission

(2) The most effective way we can alter that ratio, is by reducing the amount of biochemical energy that is used to power the biochemical processes of farm animals over the course of their lives. This is primarily a function of duration of their lives.

(3) Factory farming achieves shorter duration, by having the animals grow more quickly

(4) Another way we can reduce the net amount of CO2 produced per unit food, is by reducing the amount of land used, thus allowing less deforestation.

(5) Factory farming achieves this by using less land

(6) I cannot see any other mechanisms that differ between factory farming and organic farming which would have a major net effect on the carbon cycle.

Comment by peergynt on Why Eat Less Meat? · 2013-07-24T00:05:03.186Z · score: 3 (9 votes) · LW · GW

I only think factory-farmed meat is the problem. I use "eat less meat" as a shorthand, since nearly all meat is factory-farmed meat.

Factory-farmed meat converts photosynthetic energy (grass) to food much more efficiently than free-range farming. Factory farming requires less inputs in terms of arable land and water, and emits less CO2. If everyone in the world ate non-factory farmed meat, we would have to cut down the Amazon many times over, thereby drastically reducing earth's capacity to convert CO2 back to carbohydrates.

When you decide whether your meat should be factory farmed or not, , there are consequences on two scales that are negatively correlated: Animal welfare and global warming. Which of these scales you give most weight to, will depend on your prior for anthropogenic global warming, on your beliefs about the consequences of global warming, and on the priority you give animals in your aggregation scheme over individuals with moral standing.

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-18T17:10:05.833Z · score: 0 (2 votes) · LW · GW

What is more ridiculous about MIMO than CICO? Conservation of matter, can't argue with that.

OK, I see the point. But multicellular life evolved as thermodynamic engines, not as fusion plants. Over billions of years, cells were surviving based on how efficiently they could extract thermodynamic energy from macronutrients, to power intracellular processes. This is what we are optimized for. If we had been able to use fusion power in our evolutionary past, MIMO would be a more appropriate level at which to draw your map.

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-18T14:54:30.027Z · score: 1 (3 votes) · LW · GW

There is obviously thermodynamic energy in food which is not absorbed in the gastrointestinal tract. Fiber is an example of this. Energy which is not absorbed is not listed on the nutrition label of food. When I say 'calories', I mean the biochemically available energy in absorbed macronutrients such as fat, carbohydrates, protein and alcohol.

Nobody doubts that thermogenesis uses energy. This is a special case of my mechanism 3. It is part of the 'energy used'. Again, if you want to convince me that you can eat 3000 calories of fat without gaining weight, you would have to make an argument that the proportion of fat in my diet has a causal effect on thermogenesis, ie, that my body will start running additional thermogenesis because I ate fat instead of carbohydrates.

Your claim that CICO is as helpful as MIMO is clearly ridiculous, and if you truly believe this, then supermodels eating tissue paper are more rational than you, as their beliefs will lead to more accurate predictions.

The point I am trying to make is that our body is an efficient engine due to evolutionary pressure, that energy doesn't just disappear (if it did, we would observe large amounts of unmetabolized macronutrients in urine), and that even if CICO is not the whole picture, it explains a very large part of the variation in body weight observed in human populations

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-17T19:25:39.511Z · score: 0 (0 votes) · LW · GW

OK. I'll accept your rephrasing. Let us assume that "calories out" is always difficult to estimate and depends on a lot of factors such as muscle mass and total calorie intake.

I took the original comment to mean that we can eat very large amounts of fat and protein, because our bodies would somehow react, in response to the proportion of different nutrients in our diet, and change how efficiently we use energy. I find it difficult to believe that this would explain much of change in body weight. I find it much easier to believe that it would change our appetites and thus reduce calorie intake.

I am certainly willing to update my priors if someone convinces me of a plausible mechanism by which proportion of each nutrient alters efficiency of energy use..

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-17T19:11:27.615Z · score: 1 (1 votes) · LW · GW

This article says that there is some non-absorption of fat in healthy people, and much greater non-absorption in people with cystic fibrosis.

If you want to convince me that I should consider this when I choose the fat/carbohydrate/protein content of my diet, you would have to make an argument that the percentage of fat that is not absorbed is a function of my diet, ie, causally related to what I choose to eat.

I'm not saying this is not theoretically possible, but my intuition tells me that the variation in absorbtion that is caused by diet, is unlikely to have a major impact in the final analysis

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-17T18:58:59.070Z · score: 0 (0 votes) · LW · GW

Thank you, that was helpful.

Note that I don't disagree with anything in that Mayo Clinic article. The point about "pounds of fat, muscle and water" is obviously true and does not contradict anything I said. The points about "metabolic rate" and "response to reduced calories" just seem to say that sometimes it is difficult to estimate the "calories out" part of the equation, and that it is endogenous to the system. This is also obviously true. I still find it difficult to believe that we can affect the metabolic rate to an extent that matters in the final analysis, based on the fat/protein/carbohydrate content of our diet..

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-17T18:29:51.327Z · score: 0 (0 votes) · LW · GW

By which mechanism do these nutrients get excreted? Urine? Bile? Non-absorption?

My impression is that carbohydrates in urine is something that we only see to a significant extent when blood glucose concentration is at diabetic levels. Protein and fat in urine occurs, but it doesn't seem to me that this happens to an extent where it can make a difference to the total energy picture

I don't think excreting them through bile would work, the nutrients would just be reabsorbed further down the gastrointestinal tract.

It is possible that at very high intake levels, there is significant non-absorption of fat. Maybe this happens in competitive eaters, but I am not convinced it can explain much at fat intake levels seen in ordinary people..

Comment by peergynt on How I Lost 100 Pounds Using TDT · 2013-07-17T15:27:50.968Z · score: 2 (10 votes) · LW · GW

I am not sure I am convinced by this argument, for the following reasons:

If you think of calorie content / thermodynamics as an upper bound on how much energy can be extracted from the food, you have to make an argument for what happens to the unused energy. Even if you are in a biochemical state where not all the energy is used, there is still energy floating around in your body in the form of carbohydrates, fat and protein. I can think of three possible mechanisms for what happens to this extra energy, and I am not convinced by any of them:

(1) Calories are excreted unused in their original form. However, I don't think this happens to a meaningful extent

(2) If there is excess fat, nutrients are broken down to molecular constituents in a less efficient mechanism of cellular metabolism, ie, producing less ATP. This is a little more plausible than 1, but I think it would be evolutionary maladaptive to reduce the fuel efficiency of your engine unless it was absolutely necessary. Note that there are cases when the body does reduce the fuel efficiency (such as anaerobic metabolism), but I can't see how this applies here

(3) (Added): If there is excess fat, the body begins to run processes that are not strictly necessary, thus using more fuel. However, I am not sure what these processes would be, or why they would be triggered by fat and not carbohydrates.

I find it plausible that increasing fat intake will help you lose weight due to regulatory pathways such as insulin, but I think this pathway operates almost exclusively through changes in appetite. I fail to see any arguments why we cannot use thermodynamics (calorie input/output) as a very good approximation of predicted weight change.

EDIT: This comment is being downvoted. I am happy to delete it if it doesn't add to the discussion, but it would help me immensely if someone could explain why my reasoning is wrong...

EDIT2: I am not sure if I misunderstand the karma system, but I don't think you are supposed to downvote someone for disagreeing with their conclusions. It is possible that I am wrong in my conclusions, but I don't think this in itself is reason for downvoting.

If you disagree with my arguments, you can dissect them in the comments. Reasonable arguments with incorrect conclusions are still valuable in a discussion, and if you show why they are wrong, you will not only help me update my priors, but also help reveal a flaw in how non-trolls come to their beliefs. Hiding the comment prevents this. I don't see any reason for downvoting, and I think the downvoters need to ask themselves if they are downvoting due to mood affiliation / cognitive bias.

Comment by peergynt on Simpson's Paradox · 2011-01-15T07:48:54.930Z · score: 7 (7 votes) · LW · GW

The OP's assertion is true. Stratifying on certain variables can introduce bias.

Consider that you have a cohort of initially healthy men, and you are trying to quantify the causal relationship between an exposure (eg eating hamburgers) and an outcome (eg death). You have also measured a third variable, which is angina pectoris (cardiovascular disease).

Assume that the true underlying causal structure, which you are unaware of, is that hamburgers cause cardiovascular disease, which subsequently causes death.

Now look at what happens if you stratify on cardiovascular disease: In the strata consisting of men who don’t have cardiovascular disease, you will find no cases of death. This will lead you to conclude that in men who don’t have cardiovascular disease, eating hamburgers does not cause death. This is false, as eating hamburgers will cause them to develop cardiovascular disease and then die.

What you have done in this situation, is stratify on a mediator, thereby “blocking” the pathway running through it. There are also many other situations in which adjusting for a variable introduces bias, but it gets more complicated from here.

For further information on this I suggest reading an upcoming book called “Causal Inference”, by James Robins and Miguel Hernan, who taught me this material. The first ten chapters are available for free online at http://www.hsph.harvard.edu/faculty/miguel-hernan/files/hernanrobins_v1.10.9.pdf .