1 Hume David, A Treatise of Human Nature, ed. Selby-Bigge L.A. (London: Oxford University Press, 1973), p. 469.
2 I think it arguable that this is how Hume meant us to understand “a deduction from.” Whatever precisely Hume may have had in mind in the passage quoted in the text above, it is surely plain that he did not mean to be drawing our attention merely to the fact that “ought” is not obtainable from “is” within (as it might be) first-order logic.
3 Or you might have appealed to Moore's G.E. ‘open question’ argument from Principia Ethica (London: Cambridge University Press, 1966), pp. 15ff. See also Ayer's A.J. Language, Truth and Logic (New York: Dover Publications, 1952), ch. VI.
4 Hitler tends to turn up as an example in defense of this view.
5 That is not true of many other current moral disputes, such as the disputes about abortion. The question whether the fetus is a person – which most participants take seriously – is neither straightforwardly factual, nor straightforwardly moral.
6 A different kind of straddle judgment (that is, judgment which is neither purely moral nor purely factual) was drawn attention to by Prior Arthur N. In “The Autonomy of Ethics,” reprinted in his collection of essays Papers in Logic and Ethics (Amherst: University of Massachusetts Press, 1976).
7 See her “Moral Arguments,” reprinted in her collection of essays Virtues and Vices (Oxford: Basil Blackwell, 1978). My quotations are all from p. 102 of that edition.
8 Williams Bernard, Ethics and the Limits of Philosophy (Cambridge: Harvard University Press, 1985), pp. 129, 140.
9 Compare Searle's John route from fact to value in his “How to Derive ‘Ought’ From ‘Is’,” Philosophical Review, vol. 73 (1964), pp. 43–58. Searle begins with what is on any view a statement of fact, “Jones uttered the words ‘I hereby promise to…’,” and at the end arrives at what is on any view a moral judgment, “Jones ought to….” He breaks the step from premise to conclusion into a series of sub-steps. It is certainly plausible to think that by the time we reach “Other things being equal, Jones ought….,” we have already reached a moral judgment.
I should say, however, that I do not here endorse Searle's explanation of what makes those sub-steps acceptable.
10 And the fact that the thick ethical concepts lend themselves to this kind of argument against The Fact-Value Thesis is not a fact about them by means of which they can be distinguished from concepts – such as ‘causes a person pain’ – which I take not to be ethical concepts at all, and a fortiori not to be thick ethical concepts.
11 The notion at work here is presumably the obverse of Ross's ‘prima facie duty’. (See Ross W.D., The Right and the Good (Oxford: Clarendon Press, 1930) Nobody regards Ross as having made that notion satisfactorily clear; everyone, I think, has a sense of what notion it is that he was trying to make clear.
12 Compare Hare R.M.: “it might be said that a principle of conduct was impossible to reject, if it were self-contradictory to reject it. But if it is self-contradictory to reject a principle, this can only be because the principle is analytic. But if it is analytic, it cannot have any content; it cannot tell me to do one thing rather than another.” The Language of Morals (New York: Oxford University Press, 1965), p. 41.
13 See Kripke Saul A., Naming and Necessity (Cambridge: Harvard University Press, 1980).
14 I should think it could be said, not merely that (3) through (3′″) are moral judgments that are non-trivial necessary truths, but also that it is not at all clear how their negations could be accommodated into what would be recognizable as a moral code.
In passing, that there are moral judgments that are non-trivial necessary truths is arguably something that Hume would have denied. As I said in note 2 above, it is surely plain that Hume was not, in the well-known passage I quoted, drawing our attention merely to the fact that “ought” is not obtainable from “is” within (as it might be) first-order logic; it is arguable that he would have denied that there is any necessary connection between “ought” and “is.” Hume went on to say:
But as authors do not commonly use this precaution, I shall presume to recommend it to the readers; and am persuaded, that this small attention wou'd subvert all the vulgar systems of morality, and let us see, that the distincion of vice and virtue is not founded merely on the relations of objects, nor is perceiv'd by reason. (Treatise, pp. 469–70)
Statements whose truth is “perceiv'd by reason” are statements whose truth (if they are true) we can come to know of a priori, and – following Kripke (in Naming and Necessity) – we nowadays distinguish between the a priori and the necessary. But it is arguable that Hume did not.
15 I said this because I am inclined to think it rare that disputants on this issue disagree because they disagree about whether human acts have causes. If a pair of disputants on this issue do disagree because they disagree about whether human acts have causes, then while their dispute is presumably not settleable by appeal to evidence about human acts (or anything else), the dispute between them is not purely moral. But it is, I think, far more common for disputants about capital punishment to agree that acts have causes, and to disagree only about the moral significance to be attached to that fact.
16 The term comes, of course, from Forster's E.M. Howard's End (Harmondsworth: Penguin Books, 1941).
17 Nor do they favor execution by ghastly means. But that, I fancy, is due more to a change in conception of how much pain and humiliation may be caused in the name of a public purpose than to a change in conception of what warrants killing.
18 I should perhaps say explicitly that the people I have in mind by “moral theorists” do not include those who are primarily interested in moral epistemology or moral metaphysics.
19 The method I described is very like the process Rawls describes as the effort to reach “reflective equilibrium,” with this proviso: on Rawls's account of the matter, everything is provisional, everything is open to revision, whereas I am suggesting that some moral judgments are necessary truths, and hence not open to revision. See A Theory of Justice (Cambridge: Harvard University Press, 1971) pp. 20, 48–51.
20 I am grateful to the other contributors to this volume for helpful criticism. I owe thanks also to Jonathan Bennett, David Brink, Derek Parfit, and Warren Quinn, who made helpful criticisms of earlier versions.