Abstract

In general, properties realize certain roles in the workings of nature. For example, mass makes objects resist acceleration. But what is the relationship between these roles and the properties that realize them? According to ‘quidditism’, the roles are contingently realized by the properties that in fact realize them. Opponents charge that quidditism implies the existence of epiphenomenal and unknowable “quiddities” or “inner natures”. The purpose of this dissertation is to argue in favor of quidditism and explore its epistemic and pragmatic consequences.