Definitions of Rationality in Philosophy, Cognitive Science, and Lay Discourse

Abstract

Because rationality is an issue across many disciplines, it has acquired many different definitions. This chapter describes definitions of rationality from cognitive science that are amenable to a program of measuring individual differences. Definitions of both epistemic and instrumental rationality are described in terms in terms of axiomatic utility theory and probability theory. It is argued that the wide range of tasks investigated in the heuristics and biases literature captures most aspects of epistemic and instrumental rationality.