"There are at least five kinds of uncertainty. The first is brute factual uncertainty (will there be a major earthquake in greater Los Angeles over the next decade?). The second is higher-order uncertainty about the cost of resolving first-order uncertainty (do I have time to ascertain the enemy's position before going into battle?). The third is strategic uncertainty due to multiple equilibria (do cartel members play tit-for-tat or sudden death?). The fourth is uncertainty due to asymmetric information (is my opponent irrational or only faking?). The fifth is uncertainty due to incomplete causal understanding (will tyrannical measures imposed by a dictator make the subjects more compliant or less?). The compound effect of these (and perhaps other) forms of uncertainty will, in most complex situations, tend to be overwhelming."
-- Jon Elster, "Rational Choice Theory: A Case of Excessive Ambition," American Political Science Review 94:3 (September 2000), 693.