In this lecture, James illustrates how the pragmatic method can be applied to metaphysics. As a traditional branch of philosophy, metaphysics deals with fundamental principles such as being, existence, the nature of reality, etc. In popular usage, the word also tends to denote the more abstract or even abstruse side of philosophy. Here James engages with concepts that philosophers going back to the medieval Scholastics, and before that to Aristotle and other ancient Greek thinkers, have grappled with. He shows how pragmatism connects with these classical philosophical concerns and emphasizes the questions’ relevance for present-day debates.

First, James takes up the traditional metaphysical concept of substance. He explores how this concept relates to the question of materialism versus theism as rival explanations for how the world came to be.

Medieval Scholastic philosophy distinguished between substance—a term that denotes a thing—and attribute, which is quality inherent to the substance. For example, the attribute of hardness of a desk is inherent to its substance—wood. The philosophical thread goes on to argue that we can really only know attributes; our knowledge of substances derives from their attributes. Thus, only attributes have cash-value, or practicality—a key pragmatist idea (see Index of Terms for an explanation of cash-value).