Comprehensibility rather than beauty

Abstract

Most scientists and philosophers of science recognize that, when it comes to accepting and rejecting theories in science, considerations that have to do with simplicity, unity, symmetry, elegance, beauty or explanatory power have an important role to play, in addition to empirical considerations. Until recently, however, no one has been able to give a satisfactory account of what simplicity (etc.) is, or how giving preference to simple theories is to be justified. But in last few years, two different but related accounts have appeared, both of which address above issues. On one hand, James McAllister has argued that aesthetic criteria in science reflect scientists' judgements about what kind of theory is most likely to be empirically successful, based on relative empirical success and failure of different kinds of theories in past. Scientists employ what McAllister dubs the aesthetic induction. On other hand, I have argued that we need to see science as making a hierarchy of metaphysical assumptions about comprehensibility and knowability of universe, these assumptions asserting less and less as one ascends hierarchy. One of more substantial of these assumptions is that universe is physically comprehensible. The key non-empirical feature a body of fundamental theories in physics must possess to be acceptable is unity. The better such a body of theory exemplifies metaphysical thesis that universe is physically comprehensible, in sense that it has a unified dynamic structure, so more acceptable such a body of theory is, from this standpoint. This affects not just theoretical physics, but whole of natural science. In this paper I compare and contrast, and try to assess impartially relative merits of, these two views.