Abstract

Philosophers who have a conception of morality that allows for an ultimate conflict between duty and self-interest inherit a most difficult problem: the problem of the unity of practical reason. As long as duty is thought of as an extension of self-interest, as apparently both Plato and Hobbes thought, no theoretical difficulty arises; practical reason is unified simply because duty and interest have the same goal. But once this kind of conceptual connection between duty and self-interest is severed, the task is to avoid the philosophical nemesis of dualism, a conception of practical reason in which an individual’s choice between doing his duty and securing his interests is necessarily arbitrary as a matter of practical justification. Moreover, the difficulty is compounded when morality is conceived in such a way that a person has a morality only if his moral concerns have justificatory priority among his practical concerns. When built into the concept of morality, this sort of justificatory priority might initially appear to restore the unity lost by practical reason with the severance of duty and interest. But so achieved, the unity bears all the marks of having been gained arbitrarily, for it can just as plausibly be said that a person is an egoist only if his own interests take justificatory priority among his practical concerns. Faced then with a decision about what he ought to do in a situation in which duty and interest are in conflict, the practical reasoner confronts a dilemma. In trying to decide what he ought to do, practical reason, in the form of morality, advises him to do one thing, yet in the form of self-interest, it advises him to do another. Therefore, like Humpty Dumpty, once practical reason is shattered by the separation of duty and interest, the practical reasoner’s problem is how to put things back together again.