Look, for thousands of generations, natural selection applied its limited quantity of optimization pressure toward refining the eye. But now it's at a point where natural selection only needs a few more bits of optimization to effect a huge vision improvement by turning a great-but-broken eye into a great eye.

The fact that most people have fantastic vision shows that this trait is high utility for natural selection to optimize. So it's astounding that natural selection doesn't think it's worth selecting for working fantastic eyes over broken fantastic eyes... (Read more)(Click to expand thread. ⌘F to Expand All)Cmd/Ctrl F to expand all comments on this post

Just because you can imagine a better eye, doesn't mean that evolution will select for it. Evolution only selects for things that help the organisms it's acting on produce children and grandchildren, and it seems at least plausible to me that perfect eyesight isn't in that category, in humans. Even before we invented glasses, living in groups would have allowed us to assign the individuals with the best eyesight to do the tasks that required it, leaving those with a tendency toward nearsightedness to do less demanding tasks and still contribute to the trib... (Read more)(Click to expand thread. ⌘F to Expand All)Cmd/Ctrl F to expand all comments on this post

Two Truths and a Lie

by Psychohistorian 10y23rd Dec 20091 min read67 comments

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Response to Man-with-a-hammer syndrome.

It's been claimed that there is no way to spot Affective Death Spirals, or cultish obsession with the One Big Idea of Everything. I'd like to posit a simple way to spot such error, with the caveat that it may not work for every case.

There's an old game called Two Truths and a Lie. I'd bet almost everyone's heard of it, but I'll summarize it just in case. A person makes three statements, and the other players must guess which of those statements is false. The statement-maker gets points for fooling people, people get points for not being fooled. That's it. I'd like to propose a rationalist's version of this game that should serve as a nifty check on certain Affective Death Spirals, runaway Theory-Of-Everythings, and Perfectly General Explanations. It's almost as simple.

Say you have a theory about human behaviour. Get a friend to do a little research and assert three factual claims about how people behave that your theory would realistically apply to. At least one of these claims must be false. See if you can explain every claim using your theory before learning which one's false. 

If you can come up with a convincing explanation for all three statements, you must be very cautious when using your One Theory. If it can explain falsehoods, there's a very high risk you're going to use it to justify whatever prior beliefs you have. Even worse, you may use it to infer facts about the world, even though it is clearly not consistent enough to do so reliably. You must exercise the utmost caution in applying your One Theory, if not abandon reliance on it altogether. If, on the other hand, you can't come up with a convincing way to explain some of the statements, and those turn out to be the false ones, then there's at least a chance you're on to something.

Come to think of it, this is an excellent challenge to any proponent of a Big Idea. Give them three facts, some of which are false, and see if their Idea can discriminate. Just remember to be ruthless when they get it wrong; it doesn't prove their idea is totally wrong, only that reliance upon it would be.

Edited to clarify: My argument is not that one should simply abandon a theory altogether. In some cases, this may be justified, if all the theory has going for it is its predictive power, and you show it lacks that, toss it. But in the case of broad, complex theories that actually can explain many divergent outcomes, this exercise should teach you not to rely on that theory as a means of inference. Yes, you should believe in evolution. No, you shouldn't make broad inferences about human behaviour without any data because they are consistent with evolution, unless your application of the theory of evolution is so precise and well-informed that you can consistently pass the Two-Truths-and-a-Lie Test.

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