Rationality as a Virtue

Abstract

A concept that can be expressed by the term ‘rationality’ plays a central role in both epistemology and ethics—especially in formal epistemology and decision theory. It is argued here that when the term is used in this way, it expresses the concept of a kind of virtue, that has the central features that are ascribed to virtues by Plato and Aristotle, among others. Like other virtues, rationality comes in degrees. Just as Aristotle distinguished ‘just acts’ from acts that ‘manifest the virtue of justice’, we can distinguish the ‘abstract rationality’ from the manifestation of rational dispositions; this is the best account of the distinction between ‘propositional’ and ‘doxastic justification’. This approach also helps us to understand the relations between ‘rationality’ and ‘rational requirements’, and to answer further objections to the thesis that ‘rationality’ is a normative concept that are based on the principle that ‘ought’ implies ‘can’.