Published online by Cambridge University Press: 01 January 2020
Since the time of Hume, many philosophers have thought it impossible to deduce an ‘Ought’ from an ‘Is,’ or in general to deduce ‘ethical sentences’ from purely ‘factual sentences.’ Some of these philosophers claim that this is due, not to any Special feature of ethics, but to a general feature of logic, namely, its conservativeness:
A conclusion containing an ‘ought’ cannot (as a matter of logic) be derived from ‘ought’-free premises. (The same, of course, goes for the other moral words.) Logic is conservative; the conclusions of a valid inference are contained within the premises. You don't get out what you haven't put in. Hence if ‘ought’ appears in the conclusion of an argument but not in the premises, the inference is not logically valid.’
1 Charles Pigden suggests that the idea goes back as far as Cudworth. See Pigden, C. ‘Logic and the Autonomy of Ethics,’ Australasian Journal of Philosophy 67 (1989) 127–51.CrossRefGoogle Scholar Pigden frames his discussion in terms of ‘moral propositions’ or ‘moral judgements.’ I find that terminology natural, but my main target, Toomas Karmo, frames his discussion in terms of ‘ethical sentences,’ so I shall do likewise.
2 Pigden, Charles ‘Naturalism,’ in Companion to Ethics, Singer, P. ed. (London: Blackwell 1991), 423.Google Scholar
3 Prior, A.N. ‘The Autonomy of Ethics’, Australasian Journal of Philosophy 38 (1960),CrossRefGoogle Scholar reprinted in A.N. Prior: Papers in Logic and Ethics Kenny, A. and Geach, P. eds. (London: Duckworth 1976), 90–3Google Scholar
4 Karmo, Toomas ‘Some Valid (but no Sound) Arguments Trivially Span the “Is”-“Ought” Gap’, Mind 97 (1988) 252-7,CrossRefGoogle Scholar at 253. Karmo attributes this argument to Danny Mond. A similar argument is developed independently in Nelson, Mark T. ‘Is it Always Fallacious to Derive Values from Facts?’ Argumentation 9 (1995) 553–62.CrossRefGoogle Scholar
5 Pigden, ‘Logic and the Autonomy of Ethics’, 132Google Scholar
6 Ibid., 133, ff. See also Pigden, ‘Naturalism’, 424.Google Scholar
7 Maitzen, Stephen ‘Closing the “Is”-“Ought” Gap’, Canadian Journal of Phüosophy 28 (1998) 349–66.CrossRefGoogle Scholar
8 Berkeley gives this argument for his skepticism about physical objects, though the form of his argument is not so explicit. See A Treatise Concerning the Principles of Human Knowledge, sections 18-21. An explicit version of the argument is applied to mind-independent physical objects in Stace, W.T. ‘The Refutation of Realism’, Mind 53 (1934) 145–55.CrossRefGoogle Scholar For a discussion of the argument as applied to physical objects, the past and personal identity, see Ayer, A.J. The Problem of Knowledge (Harmondsworth: Penguin 1956), 75–81.Google Scholar Something like this argument is applied to ethics in Sinnott-Armstrong, Walter ‘Moral Skepticism and Justification’ in Moral Knowledge? New Readings in Moral Epistemology, Sinnott-Armstrong, W. and Timmons, M. eds. (Oxford: Oxford University Press 1996), 3–48, especially 10-12.Google Scholar
9 I doubt that these domains can be non-arbitrarily partitioned, but I shall ignore this doubt for the sake of argument.
10 Pigden explicitly recognizes this connection between logical autonomy and skeptical arguments. See Pigden, ‘Logic and the Autonomy of Ethics’, 130, n. 6.Google Scholar
11 As an anonymous referee for this Journal pointed out to me, it should be noted that ethical autonomism is neither a necessary nor a sufficient condition for ethical skepticism. One might accept autonomism but hold that non-inf erential knowledge of ethics is possible. Equally, one might reject autonomism but hold that ethical knowledge fails for some other reason. For a Statement of the latter position, see Sinnott-Armstrong, Walter ‘From ‘Oughf to ‘Is’ in Moral Epistemology’, Argumentation 14 (2000) 159–74.CrossRefGoogle Scholar
12 This is misleading; it is not exactly a matter of becoming ethical. As I shall explain, the change is not over time, but over possible worlds.
13 Here he follows Humberstone, Lloyd ‘First Steps in Philosophical Taxonomy’, Canadiern Journal of Phüosophy 12 (1982) 467–78.Google Scholar
14 Karmo, ‘Some Valid’, 254Google Scholar
15 Ibid.
16 Ibid, 256.
17 I am assuming here simplistic stereotypes of Kant and Machiavelli; nothing hangs on this.
18 Humberstone, ‘First Steps’, 477. Note, however, that, instead of wanting his tools to support ethical skepticism, Humberstone actually wants them to presuppose it
19 Thanks to an anonymous referee for helping me to see this.
20 Maitzen frames his discussion in terms of ‘moral propositions’ instead of ‘ethical sentences’, but I have changed it to ‘ethical sentences’, to fit in with Karmo's wording.
21 A similar criterion is developed in Nelson, ‘Is it Always Fallacious to Derive Values from Facts?’
22 Using this result, Maitzen also manages to refute Karmo's overall conclusion by constructing a counterexample: a simple Is-to-Ought argument which can plausibly be regarded as sound, but whose premises can be shown to be purely non-ethical:
B1. Some ethical sentences are true.
B2. Either no ethical sentence is true, or torturing babies just for fun is wrong.
Therefore,
B3. Torturing babies just for fun is wrong.
This argument is valid via disjunctive elimination; the conclusion is an ‘uncontroversially ethical sentence’; (B2) has already been shown to be an ethical sentence, and is true according to both nihilistic and conventional Standards. Maitzen argues that (Bl) also is a non-ethical sentence, on the grounds that we must distinguish between ‘sentences o/ethics’ and ‘sentences about ethics.’ Sentences of ethics entail that some particular moral property is possessed by some object(s) or other. (Bl) entails no such thing, so it is better classified as a sentence about ethics, on a par with, say, ‘“Morality” often goes by the label “ethics.”’ See Maitzen, ‘Closing the “Is”-“Ought” Gap,’ 361.
23 The Katyn Massacre was the execution by the NKVD in April-May, 1940 of approximately 25,700 members of the Polish intelligentsia, including 14,700 prisoners of war, in a forest near the village of Katyn, near Smolensk, Russia.
24 Because p entails ∼((p->q) & ∼q).
25 Moreover, the separate conjuncts in (JS*2) are, on Karmo's criterion, clearly ethical sentences in w, so it would be very odd if their conjunction ceased to be an ethical sentence in wl! Any argument that (JS*2) is not an ethical sentence must face up to this odd implication.
26 For example: Searle's Is-to-Ought argument, which proceeds from one epistemologically unproblematic non-ethical sentence and a number of ceteris paribus qualifiers. See ‘How to Derive “Ought” from “Is/” Philosophical Review 63 (1964) reprinted in The Is/Ought Question, Hudson, W.D. ed. (London: Macmillan 1969), 120–34.Google Scholar
27 The writing of this essay was supported by the Institute of Faith and Learning at Baylor University. I thank the Institute and the Baylor Philosophy Department for their support, and Jennifer Jackson, Robin LePoidevin, Andrew McGonigal, Stephen Maitzen, Scott Shalkowski, and two anonymous referees for this Journal for helpful comments and discussion.