Racionalidade, definições, etc.

Um artigo que me fez lembrar muito do que se discute aqui - Rational != Self-interested, de Andrew Gelman:

I’ve said it before (along with Aaron Edlin and Noah Kaplan) and I’ll say it again. Rationality and self-interest are two dimensions of behavior. An action can be:
1. Rational and self-interested
2. Irrational and self-interested
3. Rational and altruistic
4. Irrational and altruistic.
It’s easy enough to come up with examples of all of these.

Before going on, let me just quickly deal with three issues that sometimes come up:
– Yes, these are really continuous scales, not binary.
– Sure, you can tautologically define all behavior as “rational” in that everything is done for some reason. But such an all-encompassing definition is not particularly interesting as it it drains all meaning from the term.
– Similarly, if you want you can tautologically define all behavior as self-interested, in the sense that if you do something nice for others that does not benefit yourself (for example, donate a kidney to some stranger), you must be doing it because you want to, so that’s self-interested. But, as I wrote a few years ago, the challenge in all such arguments is to avoid circularity. If selfishness means maximizing utility, and we always maximize utility (by definition, otherwise it isn’t our utility, right?), then we’re always selfish. But then that’s like, if everything in the world is the color red, would we have a word for “red” at all? I’m using self-interested in the more usual sense of giving instrumental benefits.

 To put it another way, if “selfish” means utility-maximization, which by definition is always being done (possibly to the extent of being second-order rational by rationally deciding not to spend the time to exactly optimize our utility function), then everything is selfish. Then let’s define a new term, “selfish2,” to represent behavior that benefits ourselves instrumentally without concern for the happiness of others. Then my point is that rationality is not the same as selfish2. (...)

Self-interest is the end, rationality is the means. You can pursue non-self-interested goals in rational or irrational ways, and you can pursue self-interested goals in rational or irrational ways.

[O ponto principal - e titulo - do post, de que "racional" é diferente de "interesse próprio" não tem nada a ver com a discussão que referi, mas os considerandos colaterais acabam por ter]