The relationship between the notion of identity and that of reason is complex and not easy to summarize. The two most obvious intersections between the concepts of reason and identity run through the field of logic and the many popular theories of human nature in the Western philosophical tradition. This entry provides a brief account of both the role of the law of identity in logic and the identification of the human being with a rational creature.

First, however, it may be useful to understand what is usually meant by reason. Although it has ...