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In Defense of Truth-Value

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In Defense of Truth-Value CHAPTER 4 IN DEFENSE OF TRUTH-VALUE NTV owes much of its popularity, as well as its birth, to E.W. Adams --somewhat ironically, since his paper kicked off the contemporary literature on the truth conditions of conditionals.1 Dormant for some years, NTV was revived by Gibbard (1981) and further fomented by Appiah (1985), Edgington (1986) and Bennett (1988). As I have said, I reject NTV. In this chapter I shall offer some arguments against it, and then rebut the arguments for it, so that I may move on to my further truth-conditional investigations with a clear conscience. One qualification:2 I have characterized “NTV” as the thesis that indicative conditionals have no truth-values. Against that, it may be that all indicative conditionals have truth-values, but it may also be that some indicatives have truth-values and some do not. Suppose, for example, that Emotivism is true and moral judgments lack truth-value. Then a conditional with a moral judgment for a consequent (“If he has lied to his mother, that is morally wrong”) would presumably lack truth-value also, even if NTV is generally false. We should understand NTV firmly as the claim that no indicative conditional has a truth-value. But even here there are subtleties, because still in the spirit of NTV, someone might grant that noncontingent conditionals, perhaps just those that are logical truths or their negations, have truth-values even though contingent conditionals do not. I shall take this up below, in the form of an objection. Contra NTV The arguments against NTV are as follows. 1. Philosophical peculiarity. Of course some philosophers question the truth- conditional view of meaning (some question even the health of the very notion of truth). But if one accepts the truth-conditional view generally, as I do, the suggestion that, alone among 83 English declarative sentences, indicative conditionals by their nature lack truth-values is peculiar to say the least. Why would just one type of sentence, though “assertible” under specifiable conditions, be barred from truth and falsity, especially when sentences of that type admittedly have probabilities, interact in truth-seeking discourse with uncontroversially truth-valued sentences, are agreed on or disagreed over, figure in valid argument, etc.? Moreover it is very odd to talk, as Adams and Gibbard do, of a sentence’s “probability” when that term does not mean probability of being true. Further, NTV denies indicative conditionals a home in possible- worlds semantics or in any other version of a propositional theory of meaning, since as Gibbard himself puts it, NTV holds that indicatives (alone among English sentences as I said) do not express propositions at all. Even if one rejects all propositional and truth-conditional theories and inclines toward pure assertibility semantics for all of natural language, one will be hard put to explain why the assertibility-not-truth view should be so much more obviously right for indicative conditionals than for any other sentence. And consider again the matter of indicatives that are logically or otherwise necessarily true, or (not to beg the question) that would normally be regarded even by someone otherwise inclined toward NTV as being noncontingent and maximally assertible (assertible no matter what). I think NTV ought to make an exception here; if one is generally a truth-conditional semanticist and one’s usual logic is based on the idea of truth preservation, then a sentence derivable from no premises or ruled true by one’s semantics alone should be counted as true. But this would increase the philosophical peculiarity of the now thus restricted NTV: Why would just the class of contingent indicatives be so strongly set apart from other English sentences, including even necessary indicatives? 2. Linguistic bizarreness. The claim that ordinary conditional sentences lack truth- values is grossly implausible on linguistic grounds. If we maintain that a conditional like (1a) lacks truth-value even though the corresponding temporal sentence (1b) has one, we shall have to attribute that vast semantic difference solely to the lexical difference between “if” and 84 “when.” (1) a. I will leave if you leave. b. I will leave when you leave. NTV advocates are going to have to explain how it is that those two words could have virtually the same syntax but differ so drastically in their semantic treatment. Moreover and more to the point, Chapters 1 and 2 have argued that “if” and “when” exhibit dramatic semantic similarities as well, especially in regard to modification, pronominalization, and relativization (the second and third of these both requiring semantical coreference). It would be amazing if (1a) and (1b) were semantically as similar as they have been shown to be, and yet (1a) did not even have a truth condition at all.3 And consider the locution “if and when,” as in “If and when she submits a paper, we’ll read it within a month”; does NTV award that sentence a truth-value, or not? Further, NTV would have to be extended to “unless” sentences (cf. “unless and until”) and to all variants of the “in the event that” construction (“I’ll leave in the event that she does,” “In that case I’ll leave too,” etc.), as well as “on the condition that” and the like. The crass unlinguisticness of NTV becomes all the more evident when one applies it to the numerous languages that employ the same word for our “if” and “when.”4 NTV would have it that a temporal/conditional sentence of such a language has a truth condition when understood temporally, but entirely lacks one when understood conditionally. Yet speakers of such languages usually do not trouble to notice the distinction, treating “when” as simply a factive variant of “if;” the distinction is virtually pragmatic, resolved automatically by context without anyone’s noticing. Suppose you tried to tell a linguist who is a native speaker of such a language that actually the ambiguity is very dramatic, not just semantic but hyper- or metasemantic in that one of the two readings has an entirely different kind of meaning from the other’s. The linguist would think you were crazy. 85 3. Conditional speech acts. Conditionals can be used to perform speech acts among whose felicity conditions are sincerity and truth. Promising and vowing are the obvious examples: (2) MARSHA: And what if I leave? Can I count on you? JOHN: I swear it: In that case, I’ll leave with you. A truth-valueless, indeed truth-conditionless, sentence, is not a good one with which to undertake profound obligations. Suppose Marsha leaves, but John breaks his promise and stays. How can the notion of breaking a promise be explained except in terms of the truth-value of the promise’s complement? (The NTV defender is not without resources here. S/he could appeal to the idea of a conditional promise and maintain that for a conditional promise, to break it is only: not to make its consequent false when its antecedent is true. But some such extra apparatus is required, and it is a bit ad hoc.) These first three considerations of prima facie plausibility are hardly decisive. They could be overridden by a convincing direct argument for NTV. But a convincing direct argument would be needed. 4. The many parallels between indicatives and subjunctives. On the assumption (granted by Gibbard and uncontested by Adams) that subjunctive conditionals have truth conditions of the usual sort, NTV entails that indicative conditionals and subjunctives differ from each other in as fundamental a semantical way as any types of sentence could possibly differ from each other. (Gibbard seems to acknowledge this: He maintains that the superficial similarities between indicatives and subjunctives “hide... a profound semantic difference” and are “little more than a coincidence” (p. 211). If Gibbard did not exist, I would have to invent him.) But that consequence of NTV makes nonsense of the glaring parallels and analogies between indicatives and subjunctives.5 Indicatives and subjunctives are expressed by the same 86 lexemes, not only in English but in most other languages. Indicatives and subjunctives have the same syntax but for their distinctive tense and aspect differences, including their modification by “only” and “even.” More importantly, they have virtually the same logic. And they admit almost all the same paraphrases. All this is surprising, to say the least, if the two kinds of sentences differ semantically as far as any kinds of sentences might possibly differ. The matter is aggravated if we are persuaded by Dudman’s (1983, 1984a) argument that future indicatives and the corresponding future subjunctives are semantically identical (more on this in Chapter 7). The NTV defender would have to narrow her/his thesis, and maintain just that nonfuture indicatives lack truth-value. Thus, s/he would have to hold that “If you dropped that vase [at time t], your father found out” lacks truth-value, even though “If you drop that vase, your father will find out” said prior to t is true (or false). It is hard to believe that those two sentences bear “a profound semantic difference” from each other and that their similarities are “little more than a coincidence.” 5. Embedding phenomena. Indicative conditionals embed in longer sentences, both longer conditionals and complex sentences of other sorts--including, Kremer (1987) points out, propositional-attitude constructions other than belief contexts.6 That fact creates two problems for NTV: (i) When a conditional occurs embedded in that way, it is not asserted, and so we will need rules for projecting assertibility values through sentential compounding that do not presuppose that indicative conditionals ever are actually asserted.
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