Whether or not it amounts to a theory of truth or even a definition of "truth", my team customarily refers to the disquotational schema "'[P]' is true iff [P]" (where "[" and "]" are Quinean corner brackets; you know the drill) as a platitude (to wit, the "disquotational platitude", hereinafter DP) – i.e., something whose truth is not in dispute.
For example, I am inclined to say that this English sentence
(1) This is red.is true iff the object indicated is indeed red. Note that this does not solve our problem (below, concerning the status of (1) as an empirical statement or a semantic rule); but nobody said it would. All the schema does is disquote. After that you're on your own. If after being dumped into the object language we still don't know what to say about the reason we brought it up, that's not (1)'s fault, nor that of the schema. This may become clearer as we continue.
In particular, it seems to me not to matter to the truth value of (1) if it was meant as an ostensive definition of "red" rather than "just" an empirical observation about the thing indicated. If the thing isn't red then how can it function as part of an ostensive definition of "red"? And if it's red then (1) is true. When you ask me to bring you a red thing, the thing pointed to in (1) is not exempt simply because it's paradigmatic of redness. So it's red, and (1) is true, like I said.
Compare the meter stick. Sometimes people arguing in what they take to be a Wittgensteinian spirit deny that the meter stick is a meter long. As I recall, this is because (or at least if) to be "a meter long" just means that it is the same length as the meter stick, and what that means (on this view) is that if you hold it up to the meter stick they match; and of course you can't hold the meter stick itself up to the meter stick, so the idea that it is itself a meter long collapses into incoherence, making "the meter stick is a meter long" nonsensical, or at least sinnlos, and thus neither true nor false.
I get the point of saying this, which I take to be a healthy resistance to platonistic reification of things like "lengths"; but I don't think taking this line is worth it. Of course the meter stick is a meter long; that's why I can use it to measure off meter-long pieces of cloth (or wood, to make more meter sticks). There are better ways of resisting platonism than by this sort of semantic sleight-of-hand.
Note the form of that statement. Naturally most critics of this "Wittgensteinian" position are defenders of platonism in the relevant sense. If I just reject it in favor of "common sense" I look like one of these critics, or at best depriving our side of a potent weapon. Instead I say that weapon isn't worth it: it costs too much and we have better ones anyway. I'm still just as much a critic of platonism, and a follower of Wittgenstein in this respect, as anyone else.
Still, we need to account for the seeming imperviousness to empirical refutation of definitional statements; and that something is red is in most cases both contingent and empirically revisable, as are most uses of (1). This is what motivates the idea that (1) considered as a definition is neither true nor false, but instead a semantic rule for use of "red": revisable, if I want to change the way the "game" is played; but not empirically falsifiable – and thus, on this view, strictly nonsensical as an assertion of fact.
This is what I get from N.N.'s remarks on the Soh-Dan thread. The idea is also batted about by Wittgenstein in On Certainty: again, the idea is that such statements are neither true nor false, truth-values being reserved for statements which are, as we might say, moves in the game rather than rules setting out how the game (of indicating how things are by making true statements about them) is supposed to be played. But as I said, (1) doesn't seem to work for this. Let's try another sentence:
2) This color is red.I don't think this helps any. Its only function, as opposed to (1), would be to make clear that it is the color of the indicated object that you are calling "red", but it most likely already is – "red" is after all a common English color-word – and in our context it certainly is (unless you're pointing to a photograph of Red Auerbach, or indicating which sections of "The Communist Manifesto" are objectionable to your free-market sensibilites, or something). How about this one?
3) This color is called "red."This is the same as (2). Here the speaker is emphasizing the linguistic aspect of his statement, which of course you're always allowed to do; but it's still true if the thing is indeed red (that is, the color which English speakers call "red") and not otherwise, just like (1). Finally, in an effort to wrest control of the matter, we could try:
4) I will call this color "red."After trying to retreat from empirical statement (about the object and its color) to grammatical rule with (1) - (3), we finally come to a first-person statement – a statement not about the object, or even its color, but about me and my (subsequent) verbal behavior. This is what Daniel and N.N. go back and forth about on the thread.
One worry about this seems to be that if (4) is simply predictive of my future behavior, it doesn't mean what we want it to mean (this is N.N.'s point in certain comments). I myself wonder about the force of that italicized adverb.
Another reading can be paraphrased as "I intend to call this color 'red'". According to the DP, this is true iff you do indeed intend to call that color 'red'. (Again, the DP is remorselessly unhelpful here; but that's no reason to reject it as false. Instead, again, we just need to recognize that you get out what you put in, semantically speaking.) But then we get into the performative aspects of stating that you intend to do something, and what effect that has on the truth value of (4) – see esp. Daniel's remarks about Roedl there.
In any case, the trick here, for N.N. and his Hackensteinian friends, is to try to pack into the statement itself as an interpretation accomplie the idea that it is asserting a grammatical rule rather than making an empirical claim, and thus to indicate that responses of "no it isn't" will be met by "what do you mean, it isn't? I'm telling you how to use the word."
That's what leads us, finally, to N.N.'s example (replacing similar statements about bachelors, which he takes to be too baggage-laden for our purposes):
5) A blork is a purple flower.or
6) A blork is by definition a purple flower.Chew on that for now; I'll come back to talk about blorks later on.