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Closing the 'Is'-'Ought' Gap

Published online by Cambridge University Press:  01 January 2020

Stephen Maitzen
Stephen Maitzen*
Affiliation:
Dalhousie University, Halifax, NS, B3H 3J5
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Extract

In a dense and fascinating article of some ten years ago, Toomas Karmo adds his voice to the chorus of philosophers who deny the possibility of soundly deriving ‘ought’ from ‘is.’ According to Karmo, no derivation containing an ethical conclusion and only non-ethical premises can possibly be sound, where ‘sound’ describes a deductively valid derivation all of whose premises are true. He also suggests that the only valid derivations of ‘ought’ from ‘is’ will be trivial ones. His argument has, to my knowledge, gone unrebutted; on the contrary, it has won recent endorsements, some philosophers evidently believing that he has finally put to rest the issue of the logical autonomy of ethics. Against that trend, I intend to rebut his argument, both by falsifying the taxonomy on which his argument relies and by offering a nontrivial and potentially sound ‘is’-‘ought’ derivation of my own.

Type
Research Article
Information
Canadian Journal of Philosophy , Volume 28 , Issue 3 , September 1998 , pp. 349 - 365
Copyright
Copyright © The Authors 1998

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References

1 ‘Some Valid (but no Sound) Arguments Trivially Span the “Is” -“Ought” Gap,’ Mind 97 (1988): 252-7; subsequent references to this article will give page numbers only. Other members of the chorus include Borowski, E. J. ‘Moral Autonomy Fights Back,’ Philosophy 55 (1980): 95–100Google Scholar; Humberstone, I. L. ‘First Steps in Philosophical Taxonomy,’ Canadian Journal of Philosophy 12 (1982): 467–78Google Scholar, and ‘A Study in Philosophical Taxonomy,’ Philosophical Studies 83 (1996): 121-69; and Pigden, Charles R. ‘Logic and the Autonomy of Ethics,’ Australasian Journal of Philosophy 67 (1989): 127–51CrossRefGoogle Scholar; as well as many of the authors cited in Nielsen, Kai ‘On Deriving an Ought from an Is: A Retrospective Look,’ Review of Metaphysics 32 (1979): 487–514; 487 n. 1.Google Scholar

2 For example, Humberstone, ‘A Study’: ‘As Karma shows, … no sound arguments with [only] non-ethical premises have an ethical conclusion’ (152).

3 Page 253. The numbering of the steps is mine.

4 In conformity with Karmo's usage, I will be using the expression ‘ethical sentence’ rather than what Karmo (252 n. 3) concedes ‘might seem more natural,’ the expression ‘ethical proposition.’

5 According to Karmo, ‘the debate [over the logical autonomy of ethics] has suffered from an apparent assumption that if there is a coherent notion of being-ethical, then [being-ethical) is [a noncontingent property) of sentences, rather than [a contingent one)’ (252). He cites Humberstone's ‘First Steps’ as also recognizing that some sentences are only contingently ethical (252 n. 2).

6 He gives these examples. ‘It ought to be the case that all New Zealanders are shot’ is, he says, uncontroversially ethical and, indeed, ‘ethical in every possible world.’ ‘Everything that Alfie says is true’ and the compound sentence ‘Either tea drinking is common in England or it ought to be the case that all New Zealanders are shot’ are not uncontroversially ethical; they are, he says, ethical in some worlds and non-ethical in others (254-5).

7 Even Karmo's ally Humberstone thinks that ‘further discussion of what [Karmo's] “ethical standards” are and precisely how they work is called for’ (‘A Study,’ 156).

8 Kanno says nothing to rule out sentences having both of those properties, but it seems to me he has to rule them out, for reasons I give in note 24. In any event, my argument requires that I deny the existence of any such sentences-a denial which, although contentious, is dialectically legitimate in that context, as I argue below.

9 I thank an anonymous referee from this journal for suggesting that I confront these peculiar aspects of Kanno's account.

10 From B3 we can, I take it, deduce an explicit ‘ought’-conclusion, e.g., the conclusion ‘One ought not torture babies just for fun.’ To those who object that B3 isn't explicitly an ‘ought’-conclusion and that it doesn't straightforwardly entail one either, I offer a modified version of my derivation that produces an explicit ‘ought’-conclusion without sacrificing plausibility in the premises:

(B1) Some ethical sentences, standardly construed, are true.

(B2*) Either no ethical sentence, standardly construed, is true, or one ought not torture babies just for fun.

□ Therefore: (83*) One ought not torture babies just for fun.

11 The logical form of the derivation is ‘ϕ; ∼ϕ v ψ; therefore, ψ.’ So-called ‘relevance’ logicians notoriously contest the validity of disjunctive syllogism, but even a relevance logician (who doubts that disjunctive syllogism is an exceptionless rule) should see nothing wrong, as regards relevance, in my particular use of disjunctive syllogism. More to the present point, I doubt that anyone believes in the logical autonomy of ethics principally because she is suspicious of disjunctive syllogism.

12 Those attracted to ethical noncognitivism will object to my rephrasing EN in this way. On the noncognitivist view, an ethical sentence, such as B3, can fail to be true without thereby being false, since on that view ethical sentences typically lack either of the two classical truth-values. It is obvious, however, from Karmo's talk of true and false ethical sentences that he means to set aside noncognitivism, at least for the purpose of demonstrating the logical autonomy of ethics. Perhaps setting it aside is one intended effect of his stipulation that we construe sentences, including ethical sentences, ‘with their standard meanings’ (255): it seems fair to say that ethical noncognitivism construes the meanings of ethical sentences in a nonstandard way or, perhaps, that noncognitivism considers the standard way of construing ethical sentences (i.e., as typically true or false) not to be the best way of construing them. In any event, I join Karmo here in setting noncognitivism aside.

13 Surely we do not require that any genuine ethical standard be defensible; otherwise, the phrase ‘defensible ethical standard’ would be redundant (which it isn't), and ‘indefensible ethical standard’ would be a contradiction in terms (which it isn't). At any rate, Karmo does not seem to require it; one of the ethical standards he discusses requires the shooting of all New Zealanders (254-6).

14 A remark of Humberstone's suggests that he allows for the nihilistic ethical standard: he mentions an ethical standard ‘according to which killing is not wrong (perhaps because nothing is)’ (‘A Study,’ 157).

15 I thank David Robb for pressing this version of the contrary view. Some of Kanno's remarks hint at something like this version. In the context of my disjunctive premise B2, consider this remark, applied to a different disjunctive premise: ‘[T]he disjunctive premiss is ethical in w. (The disjunctive premiss has a false first disjunct in w. Consequently, its truth or falsity in w turns on [the truth of its second disjunct and thus on] the question whether the correct ethical standard prescribes or, on the contrary, refrains from prescribing the exceptionless shooting of New Zealanders)’ (256). Kanno's problem (and the reason he cannot consistently accept this version of the contrary view) is that he does not reckon with a disjunctive premise one of whose disjuncts is EN itself.

16 F* has the consequence □ (∼EN⊃ (EN is an ethical sentence)), which implies DEN when conjoined with the result, □∼(EN is an ethical sentence), for which I argued earlier.

17 As recently as ‘A Study’, Humberstone explicitly endorses Kanno's false conclusion (which Humberstone calls ‘a pleasant feature’) that ‘the class of statements ethical (or, equivalently, non-ethical) in a world is closed under negation’( ‘A Study,’ 152).

18 To put it symbolically, ϕ is an ethical sentence only if (∃x) □ (ϕ ⊃ (Mx & (∃y)(Hyx))), where “Mx” abbreviates “x is a moral property,” and “Hyx” abbreviates “y possesses (property) x.” The variable x ranges over moral properties such as rightness, wrongness, obligatoriness, permissibility, justice, injustice, and so on; y ranges over such objects as individual persons, action-types (such as lying or killing), actiontokens (such as particular lies or killings﹜, institutions, practices, customs, and the like. This formula specifies a necessary condition and not, of course, a definition, but that way it avoids defining every impossible sentence, including “2+2=5,” as an ethical sentence.

19 The objection is a familiar one, but I owe it in this particular form to an anonymous referee from this journal.

20 The second premise of my derivation becomes even more plausible if we replace it With

(B2**) Either no ethical sentence, standardly construed, is true, or torturing babies just for fun is presumptively morally wrong,

since even those hedonistic utilitarians who allow for ‘utility monsters’ can accept B2**.

21 Regarding B1 (i.e., ∼EN) as (probably) false commits one to the (probable) truth of B2 (i.e., EN v B3), and regarding B2 as (probably) false commits one to the (probable) truth of (∼EN & ∼B3) and thus, of course, to the (probable) truth of Bl. By contrast, however, regarding B1 as (probably) true does not commit one to the (probable) falsity of B2, and regarding B2 as (probably) true does not commit one to the (probable) falsity of Bl.

22 I say ‘suggests’ because Karmo does not argue for the triviality of all valid ‘is’ - ‘ought’ derivations.

23 On the classical conception of validity (according to which a derivation is valid if and only if it is impossible for its premises all to be true and its conclusion false): (i) any derivation with logically impossible or mutually inconsistent premises is classically valid, no matter what its conclusion; (ii) any derivation whose conclusion is noncontingently true is classically valid, no matter what its premises (and classically sound provided only that its premises are true). My derivation is classically valid, but not in either of those trivial ways.

24 For this reason, and in order to steer clear of a logically trivial derivation of the ethical from the non-ethical, I have not used the following, even quicker, way of rebutting Karmo: if, as some philosophers maintain (e.g., Thomson, Judith Jarvis ‘The No Reason Thesis,’ Social Philosophy & Policy 7 [1989]: 1–21; 9)CrossRefGoogle Scholar, there are noncontingently ethical, noncontingently true sentences, then those ethical sentences will be trivially derivable from any sentences at all- and soundly (though often only trivially) derivable from any true sentences at all, including any true non-ethical sentences.

25 In my forthcoming paper ‘Moral Skepticism Totters.’

26 For helpful comments on earlier versions of this paper, I am grateful to my colleagues at Dalhousie University, to two anonymous referees from this journal and, as always, to Rohan Maitzen. Research for this paper was partially supported by a generous grant from the Faculty of Graduate Studies Research Development Fund at Dalhousie.