AbstractExplanations and postulated mechanisms of motivation are traced from Hobbes to current cognitive formulations. Beginning with the hedonic principle, succeeding explanations of motivation have included drive theory, in terms of reflexive properties and in the Freudian notion of unconscious motivation, and current cognitive explanations, which have not yet been fully developed. It is hoped that the repeating cycle from rationality to irrationality and over again can be avoided in future explanations.