  One reason to suppose that preferences are not basic is that it appears, within standard decision theory, that a very large number of basic pairwise preferences are required in order to settle facts about how much one prefers A to B for arbitrary objects A and B. That is, the facts about degrees of desire can only be generated from more basic facts about pairwise preferences given a truly enormous number of basic facts about pairwise preferences. Pollock (2006) argues that the number of such facts is on the order of a billion billions at the very least, just to encode the same facts about desire and preference that could readily be generated from just three hundred basic facts about desires. From the assumption that the basic psychological facts must be physically realized in the brain, Pollock concludes that it is psychologically realistic to believe in basic desires, not basic pairwise preferences.