There is no subject to which the writers of ethical textbooks have devoted more attention than that of the relations between pleasure and desire, and yet it is surprising how little agreement their efforts have produced in philosophical circles. This failure seems to me to be chiefly due to the fact that the question is only one among the many problems of conation, and can only be discussed in that context. In consequence, there remains a very wide gap between what psychologists have to say about the analysis of conation and what ethical writers have to say about the problems of moral psychology.1 My object in writing this article is to help to bring this deplorable state of affairs to an end by expounding a theory of the relations between pleasure and desire, which is based upon a careful analysis of the facts of conation.