A claim on which certainly all moral philosophers agree is that moral judgments are practical, which is to say that they must be capable in some sense of guiding or influencing human behaviour. There is a difference of opinion among philosophers, however, on exactly how moral judgments have this power and on what consequences (if any) this has for the analysis of moral judgments, with one group holding that the practicality of moral judgments requires a very intimate relation to action which in turn radically affects their analysis, while the other sees no such consequences. This dispute, which has occurred in various forms throughout the history of philosophy, has been renewed in recent years by discussions of the relation between obligation and motivation, which are reviewed by William Frankena in and Motivation in Recent Moral Philosophy '.1 In this article he expresses the general issue in the following way : Many moral philosophers have said or implied that it is in some sense logically possible for an agent to have or see that he has an obligation even if he has no motivation, actual or dispositional, for doing the action in question; many others have said or implied that this is paradoxical and not logically possible. The former are convinced that no reference to the existence of motives in the agent involved need be made in the analysis of a moral judgment; the latter are equally convinced that such a reference is necessarily there.2 These two positions he calls externalism and internalism respectively, for, he says, the opposition in question is between those who regard motivation as external and those who regard it as internal to obligation .3 Frankena does not present these two positions as differing responses to the demand that moral judgments be practical, but he acknowledges that this is one aspect of the problem of obligation and motivation when he writes: . . . the issue is not whether morality is to be practical. Both parties agree that it is to be practical in the sense of governing and guiding human behaviour. . . . But the one party insists that judgments of obligation must be practical in the further sense that their being efficacious in influencing behaviour is somehow logically internal to lWilliam K. Frankena, Obligation and Motivation in Recent Moral Philosophy , in Essays in Moral Philosophy, ed. by A. I. Melden (Seattle, 1958), pp. 40-81 (henceforth referred to as and Motivation ). Although Frankena discusses only the recent literature, he professes to see the same problem in Aristotle's critique of Plato's idea of the good and in Hume's denial of reason in ethics. Among recent writers, many of whom will be discussed in this paper, W. D. Falk in particular, from whom Frankena derives the terms externalism and internalism, has contributed to clarifying the controversy. See W. D. Falk, 'Ought' and Motivation , Proceedings of the Aristotelian Society, 1947-48, pp. 111-138. 2Frankena, and Motivation , p. 40. 8lbid., pp. 40-1.