My definition differs from the one in Wikipedia because I require that your goals not call for any particular ritual of cognition. When you care more about winning then about any particular way of thinking - and "winning" is not defined in such a way as to require in advance any particular method of thinking - then you are pursuing rationality.

This, in turn, ends up implying epistemic rationality: if the definition of "winning" doesn't require believing false things, then you can generally expect to do better (on average) by believing ... (read more)

Eliezer said: This, in turn, ends up implying epistemic rationality: if the definition of "winning" doesn't require believing false things, then you can generally expect to do better (on average) by believing true things than false things - certainly in real life, despite various elaborate philosophical thought experiments designed from omniscient truth-believing third-person standpoints.


I think this is overstated. Why should we only care what works "generally," rather than what works well in specific subdomains? If rationality mean... (read more)

3CronoDAS11yRegarding "rationalists should win" - that still leaves us with the problem of distinguishing between someone who won because he was rational and someone who was irrational but won because of sheer dumb luck. For example, buying lottery tickets is (almost always) a negative EV proposition - but some people do win the lottery. Was it irrational for lottery winners to have bought those specific tickets, which did indeed win? Given a sufficiently large sample, the most spectacular successes are going to be those who pursued opportunities with the highest possible payoff regardless of the potential downside or even the expected value... for every spectacular success, there are probably several times as many spectacular failures.
6RobinHanson11yFor most people, most of the things they want do in fact prefer some ways of thinking, so your definition requires us to consider a counterfactual pretty far from ordinary experience. In contrast, defining in terms of accuracy-seeking is simple and accessible. If this site is going to use the word "rational" a lot, we'd better have a simple clear definition or we'll be arguing this definitional stuff endlessly.

The Costs of Rationality

by RobinHanson 1 min read3rd Mar 200981 comments


The word "rational" is overloaded with associations, so let me be clear: to me [here], more "rational" means better believing what is true, given one's limited info and analysis resources. 

Rationality certainly can have instrumental advantages.  There are plenty of situations where being more rational helps one achieve a wide range of goals.  In those situtations, "winnners", i.e., those who better achieve their goals, should tend to be more rational.  In such cases, we might even estimate someone's rationality by looking at his or her "residual" belief-mediated success, i.e., after explaining that success via other observable factors.

But note: we humans were designed in many ways not to be rational, because believing the truth often got in the way of achieving goals evolution had for us.  So it is important for everyone who intends to seek truth to clearly understand: rationality has costs, not only in time and effort to achieve it, but also in conflicts with other common goals.

Yes, rationality might help you win that game or argument, get promoted, or win her heart.  Or more rationality for you might hinder those outcomes.  If what you really want is love, respect, beauty, inspiration, meaning, satisfaction, or success, as commonly understood, we just cannot assure you that rationality is your best approach toward those ends.  In fact we often know it is not.

The truth may well be messy, ugly, or dispriting; knowing it make you less popular, loved, or successful.  These are actually pretty likely outcomes in many identifiable situations.  You may think you want to know the truth no matter what, but how sure can you really be of that?  Maybe you just like the heroic image of someone who wants the truth no matter what; or maybe you only really want to know the truth if it is the bright shining glory you hope for. 

Be warned; the truth just is what it is.  If just knowing the truth is not reward enough, perhaps you'd be better off not knowing.  Before you join us in this quixotic quest, ask yourself: do you really want to be generally rational, on all topics?  Or might you be better off limiting your rationality to the usual practical topics where rationality is respected and welcomed?