Traditionally, philosophy held that truth is a relationship between the knower and the thing known, expressed as the agreement between the mind and reality. James rejects this theory in favor of one that sees truth as a process or an achievement of the human mind. In Lecture 6, James defines true ideas as “those that we can assimilate, validate, corroborate and verify. False ideas are those that we cannot” (77). This is a pragmatic definition—it expresses the practical effect that having true ideas has. James’s definition also implies that truth is the result of a process of thinking rather than a simple, immediate relationship with reality. This leads James to argue that:

The truth of an idea is not a stagnant property inherent in it. Truth happens to an idea. It becomes true, is made true by events. Its verity is in fact an event, a process: the process namely of its verifying itself, its veri-fication. Its validity is the process of its valid-ation (77–78).

James describes this “verification” as a “function of agreeable leading” (78), whereby the mind is guided through a chain of inference or logic from the original idea to other “parts of experience” (78) that harmonize with the idea.