8/07/2010

New theory on human reasoning: We evolved to argue, not to be right

The argument of this Newsweek article on why we reason badly seems pretty stupid. It posits that we commit logical fallacies because they make us sound more convincing to other people. (Note that it never explains why we would find an illogical argument more persuasive in the first place. Which, if you think about it, is the same question in a different guise. So, instead of explaining why humans are illogical, the article actually defers the question while pretending to answer it).

Let's grant that a fallacious argument makes us sound more convincing when we argue with other people (I agree that it often does). Why would we have evolved to argue with each other? Even assuming that speech evolved long enough ago that we would evolve other abilities in response to having it, what reason do we have to privilege arguing as so important to survival? (IMO, this is the fallacy of assuming that because something is the case now, it must have been in the distant past).

I think it's more likely that we evolved to reason roughly and inaccurately without looking for counterexamples because that's what's necessary to act in a world that changes quickly and unpredictably. (Think about how many people would be crushed in avalanches or eaten by saber-toothed tigers while sitting around trying to think up a counterexample).