Rationality in medicine is frequently construed as hypothetico-deductive. This article argues that such a model gives a distorted view of the rational character of an enterprise that makes judgments about individual human well-being. Medicine as a science is a practical human science. Seen as such, its rational orientation is one that applies general knowledge to particular situations. It is argued that such an orientation is not deductive but interpretative. The Aristotelian concept of practical wisdom ('phronesis') is used as a model of the rational orientation of clinical judgment.