Last updated 03/18/07.
Published on: February 17, 2000
Ask your average person what rationality is, and they will inevitably come up with a charicature, like Spock from Star Trek, Sherlock Holmes, Mentor of Arisia, or some other fictional character. Political and philosophical arguments are full of claims about rationality of postions, all contradicting each other. What do we really mean by the word rational?
Usually, "rationality" is a Humpty-Dumpty word, that means whatever the user finds is convenient to club his oponents with. Either by defining rationality to specifically disclude an opponent's methods (as objectivists do) or by making rationality so diffuse that all the users methods are included (much the same way new-agers use the term "energy".)
Pop quiz time: Which of these would you call rationality? Deduction, induction, abduction, science, experimentation, heuristics, tradition, faith, imitation, guesswork, dreaming, tripping, learned reflex, unlearned reflex, tropism, metabolism? The list can go on very extensively.
Trick question! There is extensive debate among philosophers and scientists as to just what rationality really is. I think we simply ought to agree that when we use a contestable word like "rationality", we state what sense we're using it in. Just as economists have to specify whether they mean Pareto efficient or Caldor-Hicks efficient or one of the myriad other forms of efficiency they have defined.
Real-life thinking incorporates all of those listed methods, and perhaps many more. How would we decide which are more rational?
Perhaps the answer lies in WHEN they are used, under what conditions. What we would call rational then would be the methodology which gives the best results. For example, deduction in mathematics, but in situations with very incomplete information and little time to make a decision, a heuristic like one of the informal fallacies could give a decision where deduction just can't work. Quite a bit of research is being performed on how people really do think, and how reliable the results are. Three recent books are:
Simple Heuristics That Make Us Smart
by Gerd Gigerenzer et al.
How We Know What Isn't So : The Fallibility of Human Reason in Everyday Life by Thomas Gilovich
Inevitable Illusions : How Mistakes of Reason Rule Our Minds by Massimo Piattelli-Palmarini
or you can search the subject Reasoning.
For example, the first book describes some very simple methods of making judgements that, seem to be used by humans, require very little information, require very little calculation, and perform comparably to very sophisticated regressions in certain common sorts of environments. Interestingly, some of these are non-monotonic, ie. given the same data but reordered, some of the heuristics can give diffferent answers (because stopping rules are triggered before all the data is processed.)
But underlying all judgements of "rationality" are the assumptions that go in to the model by which we evaluate the results. For example, if we are looking for the "rational maximizer" of some economic theory (which doesn't match actual human behavior very well.)
We've still got a huge, incommensurate bundle of things that we call "rationality". If we put any two people to the same problem, likely they will use different "rational" methods to solve it, and get different results. I'm not sure we'll be able to use such a term for anything profitable: and indeed, I think that's where a huge amount of fallacy lies in philosophy.
When we actually examine what we're likely to call "rationality", we've got an amazing waffle-word, that can shift in meaning to make almost any argument "work". When people try to pin it down too exactly, they end up excluding a great deal of actual human behavior, which ends up making their argument invalid for that reason.
In short, "rational" is a call for raising skeptical hackles, especially when used in an adversarial context.
Copyright 2001 by Mike Huben ( firstname.lastname@example.org ).