Luke Fenton-Glynn (UCL): Unsharp Best System Chances

Luke Fenton-Glynn (UCL)

Title: ‘Unsharp Best System Chances’

Time: 5:15pm – 6:45pm

Abstract: Much recent philosophical attention has been devoted to variants on the Best System Analysis of laws and chance. In particular; philosophers have been interested in the prospects of such Best System Analyses (BSAs) for yielding *high-level* laws and chances. Nevertheless; a foundational worry about BSAs lurks: there do not appear to be uniquely appropriate measures of the degree to which a system exhibits theoretical virtues; such as simplicity and strength. Nor does there appear to be a uniquely correct exchange rate at which the theoretical virtues of simplicity; strength; and likelihood (or *fit*) trade off against one another in the determination of a best system. Moreover; it may be that there is no *robustly* best system: no system that comes out best under *any* reasonable measures of the theoretical virtues and exchange rate between them. This worry has been noted by several philosophers; with some arguing that there is indeed plausibly a set of tied-for-best systems for our world (specifically; a set of very good systems; but no robustly *best* system). Some have even argued that this entails that there are no Best System laws or chances in our world. I argue that; while it *is* plausible that there is a set of tied-for-best systems for our world; it doesn’t follow from this that there are no Best System chances. (As I will argue; the situation with regard to laws is more complex.) Rather; it follows that (some of) the Best System chances for our world are *unsharp*.