The “Is-Ought” Passage

Abstract

No discussion of Hume’s ethics, and particularly of his considerations of the role of reason in moral decisions, could be considered adequate if it did not take into account the famous “is-ought” passage. It is with this passage that this chapter deals. There are at least two good reasons for devoting a separate chapter to the discussion of this passage. First of all, in the preceding chapter, I pointed out how the arguments of section I, those directed against the rationalists, bear out my thesis that Hume is (a) primiraly concerned with exciting reasons and disregards justifying reasons, and (b) that he contends that reason is not the source of moral distinctions because reason cannot cause actions. The last chapter further illustrated that Hume, in collapsing justifying and exciting reasons, i.e., in considering exciting reasons as the only type of reasons that justify the course of action taken, has inextricably bound up the notion of obligation with the notion of having a cause for doing an act. And this means that a motive is necessary in order for there to be an obligation. All of the arguments of section I rest on these points, and by analyzing these arguments Hume offers against the rationalists I tried to substantiate my arguments of Chapters III and IV. But the “is-ought” passage, though it is in section I, does not, on the face of it, seem to involve these points. The “is-ought” passage seems, to many commentators and ethicists, to make an argument that is obvious in meaning just from considering the paragraph itself. Most anti-naturalists, for example, appeal to Hume’s “is-ought” passage as the first clear statement of the position that from factual assertions we cannot deduce moral assertions. This passage is, consequently, probably the most quoted passage of Book III. However, what Hume means in this passage is not altogether clear, as I shall point out, and this passage, if we are to understand what Hume meant by it, must be interpreted in light of his previous considerations in section I. I think we will find that Hume is really unaware of the naturalist-anti-naturalist controversy, and intends to say nothing on such an issue.