Of all the axioms of utility theory, the completeness axiom is perhaps the most questionable. - Robert Aumann, Nobel Prize Winner One of the reasons you keep a well-stocked wallet in your pocket is because you don't know very much about yourself. Know thyself , as the Greeks say, and you can skimp on the amount of media-of-exchange you keep on hand. Greater self-awareness leads to a cleaner "mapping out" of an individual's tastes and the preferred timetable for the enjoyment of those tastes. For instance, a moment of self reflection might lead you to conclude that pistachio ice cream at 8:31 PM next Friday is the best possible state of the world. If a complete set of futures markets exists, you can purchase a futures contract that is time stamped to deliver pistachio ice cream at 8:31 PM Friday, guaranteeing ahead of time that your tastes will be satisfied. The problem is that introspection is difficult. We simply don't have the time, knowledge, or energy to ...