Ancient Relativity

Relativity is the phenomenon that things relate to things: parents to their offspring; doubles to halves; larger things to smaller things. This book is about how ancient philosophers, particularly Plato, Aristotle, the Stoics, and Sextus Empiricus, understood this phenomenon and how their theories of relativity affected, and were affected by, their broader philosophical outlooks. Many scholars have thought that ancient thinkers were either fundamentally confused about the phenomenon of relativity, or held a view that is a trivial variation on a modern view. This book argues that neither is the case. In fact, ancient philosophers shared a close-knit family of views, referred to as ‘constitutive relativity’: a relative is not simply linked by a relation, but is constituted by it. The book shows that this view is present in Plato, and is exploited by him in some key arguments concerning the Forms and the partition of the soul. Aristotle adopts the constitutive view in his discussions of relativity in Categories 7 and the Topics, and retains the constitutive view in his later discussion in Metaphysics 5.15. The Relatives Argument of Aristotle’s lost work On Ideas also involves constitutive relativity. The book moves on to examine a complex report of Stoic relativity and the role relativity played in Stoic philosophy. Finally, the book discusses Sextus Empiricus’ way of thinking about relativity, which does not appeal to the nature of relatives, but rather to how we conceive of things as correlative.