It has long been believed that if man had a special function appropriate to him, and that if we could discover what it was, then we would be in a perfect position to solve all of the basic problems of ethics. For if we were, for example, shovels, and knew ourselves to be shovels, then we would also know that to spend our lives in digging would best serve our fundamental interests, realize our highest aspirations, and be in every respect the correct thing to do. Or so the theory goes; a theory which is shared, interestingly enough, by Aristotle and Sartre, even though they share little else, and even though one of them believes that man has a function and the other does not.