The title of this paper is in many ways a bad one, but it does have the advantage of familiarity, and so indicates a well-known group of questions. The questions which philosophers who have talked about “Reason and Conduct” have really been discussing and which they help us to answer have been these: “What are the various ways in which the words “reasonable,” ‘wise,’ ‘foolish,’ etc., are used?” “In what senses may actions and choices be called ‘reasonable,’ and are these senses of ‘reasonable’ connected in any way, and if so in what way, with the senses in which beliefs and inferences may be called ‘reasonable’?” In other words our questions are, in a broad sense of the word, logical questions, not empirical ones. It is misleading to say, therefore, as philosophers commonly do, that we are discussing the relationship between Reason and Conduct, or that we are going into the question of whether Reason can or cannot be practical. Reason is the faculty of acting reasonably. If under “acting reasonably” we include only “inferring properly,” then Reason can only be logical. If under “acting reasonably” we also include making correct inductions and concocting good theories then Reason can also be scientific. If under “acting reasonably” we include “acting morally” or “doing one's duty,” then Reason can be practical. The dispute about whether Reason can be practical is not merely verbal but trivial, and only appears not to be trivial when we hypostatize this faculty Reason and suppose it to be a thing. It then looks as though our dispute is an empirical one about what this thing Reason can do.