Substance: Its Nature and Existence investigates the very nature and existence of individual substances, including both living things and inanimate objects. It provides an accessible introduction to the history and contemporary debates of this important and often complex issue.

Starting with a critical survey of the main historical attempts by Aristotle, Descartes, Spinoza, Locke and Hume to provide an analysis of substance, the authors present the view that a substance must satisfy an independence condition which could not be satisfied by an insubstantial entity. Throughout the book, the authors also consider problems for the notion of substance raised by the unity of the parts of organisms and explore the problem of how we can actually know what kinds of physical substance there are.