Abstract: Examines the motivational power of practical reasoning. Two views are distinguished: “the antecedent motivation theory,” according to which, in actual human beings, all motivation nonaccidentally produced by practical reasoning issuing in a belief favoring a course of action derives, at least partly, from motivation already present in the agent; and “the cognitive engine theory,” according to which, in actual human beings, some instances of practical evaluative reasoning nonaccidentally produce motivation that does not derive at all from motivation already present. The former view is defended and the latter is criticized. Bernard Williams's defense of the former view is argued to be unsuccessful; alternative arguments for it are advanced.

Keywords: antecedent motivation theory, belief, cognitive engine theory, motivation, motivational power, practical reasoning, Bernard Williams,