is equivalent to questions that are explicitly about language, such as these:
Is the sentence “Mars was always either dry or not dry” true? (Does it express a truth as used in this context?)
Did Mars always belong either to the extension of the word “dry” or to the anti-extension of “dry” (as the word “dry” is used in this context)? (1970: 11).
But parallel reasoning would lead to the conclusion that the unphilosophical question “Was Mars always either uninhabited or not dry?” is also implicitly about language, since it is equivalent to these questions:
Is the sentence “Mars was always either uninhabited or not dry” true? (Does it express a truth as used in this context?)
Did Mars always belong either to the extension of the word “uninhabited” or to the anti-extension of “dry” (as the word “dry” is used in this context)?
Indeed, we could make parallel arguments for all everyday and scientific questions. Since they are not all about language in any distinctive sense, the reasoning does not show that the original question was about language in any distinctive sense. Even if the equivalences did show that the original question was in some sense implicitly about language, they could be read in both directions: they would also show that the explicitly metalinguistic questions were in an equally good sense implicitly not about language.
The equivalences between the questions are in any case uncontroversial only if the corresponding disquotational biconditionals are:
(T1) “Mars was always either dry or not dry” is true if and only if Mars was always either dry or not dry.
(T2a) For any time t, Mars belongs to the extension of “dry” at t if and only if Mars is dry at t.
(T2b) For any time t, Mars belongs to the anti-extension of “dry” at t if and only if Mars is not dry at t.
On the face of it, these biconditionals express at best contingent truths. For perhaps the word “dry” could have meant wet, in which case Mars would have belonged to the extension of “dry” when wet and to the anti-extension of “dry” when dry: for we use the word “dry” to mean dry even when we are talking about circumstances in which it would have meant something else, because we are not talking in those circumstances. If so, T2a and T2b do not express necessary truths. Similarly, perhaps the sentence “Mars was always either dry or not dry” could have failed to express a truth even though Mars was always either dry or not dry, since “always” could have meant never. On this reading, T1 does not express a necessary truth. We should not assume that a useful notion of aboutness would transfer across merely contingent biconditionals. Perhaps we can instead interpret T1, T2a, and T2b as expressing necessary truths by individuating linguistic expressions so that their semantic properties are essential to them; whether that requires treating the quoted expressions as necessary existents is a delicate matter. In any case, some theorists of vagueness have denied even the actual truth of biconditionals such as T1, T2a, and T2b; they might respond to the original question in one way and to the explicitly metalinguistic questions in another.4 Thus the questions are not pragmatically, dialectically or methodologically equivalent within the context of debates on vagueness. For present purposes, we need not resolve the status of the disquotational biconditionals, because we have already seen that the sense in which they make the original question implicitly about words is too indiscriminate to be useful.
We can argue more directly that the original question is not implicitly about the word “dry” by appeal to a translation test. For consider the translation of the original question into another language, such as Serbian:
Da li je Mars uvek bio suv ili nije bio suv?
The Serbian translation is not implicitly about the English word “dry.” But since the questions in the two languages mean the same, what they are implicitly about (in the same context) should also be the same. Therefore, the original question is not implicitly about the word “dry.” By similar reasoning, it is not about any word of English or any other language. Of course, given the informality of the notion of implicit aboutness, the argument is not fully rigorous. Nevertheless, the translation test emphasizes how far one would have to water down the notion of reference in order to reach a notion of implicit aboutness on which the original question would be implicitly about a word.
The translation test does not show that the original question is not implicitly about a concept, something like the meaning of a word rather than the word itself, for the English word “dry” and its Serbian synonym “suv” both express the concept dry. But what basis is there for the claim that the original question is implicitly about the concept dry? We might argue that the original question is in some sense equivalent to a metaconceptual question:
Did Mars always belong either to the extension of the concept dry or to the anti-extension of dry?
For we might apply the notions of extension and anti-extension to concepts by means of biconditionals similar to T2a and T2b respectively:
(TC2a) For any time t, Mars belongs to the extension of dry at t if and only if Mars is dry at t.
(TC2b) For any time t, Mars belongs to the anti-extension of dry at t if and only if Mars is not dry at t.
TC2a and TC2b can express necessary truths more easily than T2a and T2b can, for the apparently contingent relation between words and their meanings has no straightforward analogue for concepts. Concepts are individuated semantically: rather than merely having meanings, they are meanings, or something like them.5 Nevertheless, the argument that the original question is implicitly about the concept dry in virtue of being equivalent to the metaconceptual question wildly overgeneralizes, just like the argument that the original question is implicitly about the word “dry” in virtue of being equivalent to the metalinguistic question. For parallel reasoning would lead to the conclusion that the unphilosophical question “Was Mars always either uninhabited or not dry?” is implicitly about the concept dry, and likewise for any other unphilosophical question. Since those questions are not about concepts in any distinctive sense, the original reasoning does not show that the original question is about concepts in any distinctive sense. Even if the equivalences did show that the original question was in some sense implicitly about thought, they can be read in both directions: they would also equally show that the explicitly metaconceptual questions were in an equally good sense implicitly not about thought.
A Fregean might argue: the original question is explicitly about the concept dry, because it contains the predicate “… is dry” (in the past tense), which refers to the concept dry. In that sense, the question “Was Mars always either uninhabited or not dry?” would also be explicitly about the concept dry. However, the Fregean is not using the word “concept” with its contemporary meaning, on which concepts are something like mental or semantic representations, closer to the realm of sense than to that of reference. The Fregean referent of a predicate (a Fregean concept) is simply the function that maps everything to which the predicate applies to the true and everything else to the false: it could be treated as the extension of the predicate, except that in Fregean terms it is a function rather than an object. If the predicate refers to the property of dryness or to the set of dry things, then the original question is about the property of dryness or the set of dry things, but that has no tendency to show that it is about thought. Similarly, the Fregean claim has no tendency to show that the question is about thought, for the Fregean concept is in the realm of reference, not in the realm of thought. Like the property and the set, it is no sense but something to which a sense may determine reference. Since it is no sense, it
