Is irrationality necessary?

Much has been made lately of the anti-science stance of a large segment of the US population. (See for example Chris Mooney’s book). The acceptance of anthropomorphic climate change or the theory of evolution is starkly divided by political inclinations. However, as I have argued in the past, seemingly irrational behavior can actually make sense from an evolutionary perspective. As I have posted on before, one of the best ways to find an optimal solution to a problem is to search randomly, the Markov Chain Monte Carlo method being the quintessential example. Randomness is useful for searching in places you wouldn’t normally go and in overcoming unwanted correlations, which I recently attributed to most of our current problems (see here). Thus, we may have been evolutionarily selected to have diverse viewpoints and degrees of rational thinking. Given some situation, there is only one rationally optimal response and in the case of incomplete information, which is almost always true, it could be wrong. Thus, when a group of individuals is presented with a challenge, it may be more optimal for the group if multiple strategies, including irrational ones, are tried rather than putting all the eggs into one rational basket. I truly doubt that Australia could have been discovered 60 thousand years ago without some irrationally risky decisions. Even within science, people pursue ideas based on tenuous hunches all the time. Many great discoveries were made because people ignored conventional rational wisdom and did something irrational. Many have failed as a result as well. However, society as a whole is arguably better since generally success goes global while failure stays local.

It is not even necessary to have great differences in cognitive abilities to produce a wide range in rationality. One only needs to have a reward system that is stimulated by a wide range of signals.  So while some children are strongly rewarded by finding self-consistent explanations to questions others are rewarded by acting rashly. Small initial differences would then amplify over time as the children seek environments that maximize their rewards. Sam Wang and Sandra Aamodt covered this in their book, Welcome to Your Brain. Thus you would end up with a society with a wide variety of rationality.



3 thoughts on “Is irrationality necessary?

  1. A semantic point: For an act to be irrational, it should be something that, based on facts and/or past experiences, is likely to lead to a non-optimal outcome. So based on the argument above, which I mostly agree with, none of these science-related behaviors or attitudes can even be labeled as irrational.


  2. @jon That was essentially my point. However, I would say a fair definition is that you can’t condition on outcome. Sometimes, bad decisions or mistakes work out. I would count those as irrational, although on the meta-level it is rational from the perspective of the group.


  3. a phrase i often hear is ‘the definition of insantity is to keep repeating what you have done even if it doesn’t produce the result you want’. insanity is seen, i think, as a kind of irrational behavior. from this view just about anything can be seen as irrational—eg the scientific search for the TOE, explaining bell’s theorem, studying the mind/cognition, seeking the beginning and end of the universe.

    ratiojnality seems to be contextual. a fly trying to get out a window may die before figuring out the correct way or if it futile, but that may be due to innate algorithms for behaviors as well as lack of ability to see the whole window or find the open one. but it in a sense can be seen as acting optimally.

    i dont think ir/rationality often can be defined —‘strategy of the genes”? those are always contextual—a pathogen may be more optimal / rational than someone with a PHD. math and logic may be the most rational since they are based on strict axioms, but then there are questions whether the axioms are optimal, and also the formalism (form of the argument such as leibniz versus newton versus current forms of calculus –or even computational versions, or figuring out geometry could be converted to algebra, like imaginary numbers).


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