This is true. But it does not mean that X is Y, which is where the claim becomes substantive. And it undermines your original point, which was that what it means e.g. to be a horse depends on how people use the word, which is false. — The Great Whatever

If the truth of "X is Y" is dependent on "X" meaning "Y", and if "X" meaning "Y" is dependent on how we use the word "X", then the truth of "X is Y" is dependent on how we use the word "X". And if that "X is Y" is true is that X is Y then that X is Y is dependent on how we use the word "X".

If the truth of "horses are equine animals" is dependent on "horse" meaning "equine animal", and if "horse" meaning "equine animal" is dependent on how we use the word "horse", then the truth of "horses are equine animals" is dependent on how we use the word "horse". And if that "horses are equine animals" is true is that horses are equine animals then that horses are equine animals is dependent on how we use the word "horse".

This is the consequence of Wittgenstein and Tarski.

And if that "X is Y" is true is that X is Y then that X is Y is dependent on how we use the word "X". — Michael

This is wrong. "X is Y" is not true just in case X is Y. The words can be used to mean anything you like, and in particular, if "X" and "Y" meant something other than they do now, the truth of "X is Y" would clearly in no way guarantee that X is Y.

For example, if "horse" meant "rabbit," "Horses are rabbits" would be a true sentence, and yet horses would not be rabbits (which is absurd). This is the prejudice that is mistaken.

And if that "horses are equine animals" is true is that horses are equine animals — Michael

Again, this is wrong. Horses are equine animals; this is not because of, or equal to, any words meaning the same thing. Horses are equine animals even if there is no language at all.

"X is Y" is true iff X is Y.

No. For example, in a language in which "horse" and "rabbit" are synonyms, "Horses are rabbits" is true, yet horses are not rabbits (which is absurd; horses are not rabbits, and changing words around will not make them rabbits).

"Horses are equine animals" is true iff horses are equine animals.

No. Horses are equine animals, period, regardless of whether any sentences are true at all. Horses being equine animals is in no way dependent on language, so their being equine animals cannot be equivalent to any sentence being true.

Horses were equine animals before there was any language, because to be an equine animal just is to be a horse, ergo, it is false that 'horses are equine animals iff "horses are equine animals" is true,' since they were equine animals (that is, they were horses), long before there were any sentences to be true.

Clearly this is a lost cause. Thanks for the discussion anyway.

Okay, let me try to break this down. You claim:

"Horses are equine animals" is true iff horses are equine animals.

Here is the proof that this is false. By the right-to-left of the biconditional, this follows:

If horses are equine animals, then "horses are equine animals" is true.

Now consider a case before the advent of language. Since there is no sentence "horses are equine animals," a fortiori such a sentence cannot be true. But then, by modus tollens, it follows that in this case, horses are not equine animals.

But to be a horse just is to be an equine animal. Therefore, it follows that in this case, horses are not horses.

But this is a contradiction; so you are wrong.

But to be a horse just is to be an equine animal. — The Great Whatever

Is what you say here true? If so, what does its truth have to do with horses being equine animals? Nothing? So I can, in principle, accept the truth of your claim "to be a horse just is to be an equine animal" but not accept that to be a horse just is to be an equine animal, or accept that to be a horse just is to be an equine animal but not accept the truth of your claim "to be a horse just us to be an equine animal"?

Doesn't this strike you as nonsensical?

Surely if I accept the truth of your claim "to be a horse just is to be an equine animal" then ipso facto I accept that to be a horse just is to be an equine animal, and vice versa.

The shema that Michael is making use of is the the T-shema used by Tarski to give a recursive definition of the predicate "... is true" for a given formal language. What figures on the right of the shema is a sentence expressed (i.e. used) in a meta-language independently understood by the theorist who understands, or stipulates, the meanings of the terms used in the formal language according to some specific semantic interpretation or model.

In the context of such a theory, it may be correct to say, for instance, that:

(1) "Horses are equine animals" is true iff horses are equine animals

According to the very same semantic model for the modern English language, one could translate this shema in French thus:

(2) "Horses are equine animals" est vrai ssi les chevaux sont des animaux équestres.

The same object language is the topic -- English -- but the meta-language has been switched to French. Yet the shema says exactly the same thing. This ought to be clear to TGW (and to Tarski and Wittgenstein), but it ought to be baffling to Michael, it seems to me.

Why ought it be baffling to me?

Why ought it be baffling to me? — Michael

That's because in the second shema -- (2) -- the sentence mentioned on the left has no incidence whatsoever on the meaning of "cheveaux" and "animaux equestres" as they are being used in the meta-language. But this is true also for the case of the first shema -- (1). It is, on the contrary, the independently understood meanings of the words used on the right hand side that are being relied on order to specify or define the meanings of the words of the object-language that are being mentioned (and not used) on the left hand side of the shema.

The main point is that the truth conditions expressed by the sentences being used on the right-hand side of both shemas only depend on what is the case in the world (i.e. the extra-linguistic world) regarding horses and equine animals, and don't depend on any kind of linguistic stipulation embodied in the truth theory which the T-shema is a theorem of.

The main point is that the truth of the claims expressed by the sentences being used on the right-hand side of both shemas only depend on what is the case in the world (i.e. the extra-linguistic world) regarding horses and equine animals, and doesn't depend on any kind of linguistic stipulation embodied in the truth theory which the T-shema is a theorem of. — Pierre-Normand

Doesn't this then entail that the below is correct?

"Horses are rabbits" is true iff horses are equine animals

Is what you say here true? — Michael

Yes, that's why I said it.

If so, what does its truth have to do with horses being equine animals? Nothing? — Michael

In the language as it is now used, it reports that horses are equine animals, which is true. This in no way means, as you think, that horses being equine animals is dependent upon the language I speak existing at all. They are, and always were, equine animals regardless.

So I can, in principle, accept the truth of your claim "to be a horse just is to be an equine animal" but not accept that to be a horse just is to be an equine animal, or accept that to be a horse just is to be an equine animal but not accept the truth of your claim "to be a horse just us to be an equine animal"?

In principle, yes, if the language were different! This is precisely the point. If 'horse' meant 'rabbit,' You could very well accept the claim that 'horses are rabbits' is true, yet for all that you would not accept, as you seem to think, that horses are rabbits. Rather, since 'horse' meant 'rabbit,' you would be accepting that rabbits are rabbits.

Doesn't this strike you as nonsensical? — Michael

No; I think, again, you are deeply confused about use and mention. The above argument, to which you are not responding, is meant to show this. But to bring it home, let me generalize to the worst case.

According to your claim, with the biconditional, for any sentence "P," if P, then it must be that "P" is true.

Now, it follows from this that before language existed, there was nothing, as follows:

Consider a case where there is no language, and so there are no sentences. You have agreed that whether a sentence is true or not depends on the way it is used; and since no language exists, a fortiori no language is used, and therefore no sentence is true. So I can take any P, and it will not hold, since nothing can hold unless the corresponding sentence "P" is true.

So since in such a case "something exists" is not true, since there are no sentences and so no true sentences, it follows that it is not the case that something exists.

And you can do the same for any sentence you like, to prove any absurdity you like.

Your problem is in thinking that everything depends on language as it is used now in order to be so; but it does not. And this is why the iff schema you present is clearly false.

Surely if I accept the truth of your claim "to be a horse just is to be an equine animal" then ipso facto I accept that to be a horse just is to be an equine animal, and vice versa. — Michael

You do, if the language is as it currently is, but counterfactually, if the words mean different things, you obviously do no such thing. Yet these counterfactual situations are precisely what is of interest in the iff claim.

Doesn't this then entail that the below is correct?

"Horses are rabbits" is true iff horses are equine animals — Michael

This might be true in relation to some language where "rabbits" is used to refer to what we are referring to, in English, with the phrase "equine animals". But I don't see your point. Horses still are equine animals whatever linguistic stipulations might be in use in this or whatever alternative linguistic community.

In the language as it is now used, it reports that horses are equine animals, which is true. This in no way means, as you think, that horses being equine animals is dependent upon the language I speak existing at all. They are, and always were, equine animals regardless. — The Great Whatever

You're still missing the point. You say that there were bachelors before we started using the word "bachelor". I ask you by what virtue. You say by virtue of there being unmarried men before we started using the word "bachelor". I ask you what unmarried men have to do with bachelors. You say that to be a bachelor just is to be an unmarried man. I ask you what makes this the case.

So what makes it the case that to be a bachelor just is to be an unmarried man? The fact that we use the terms "bachelor" and "unmarried man" to refer to the same sort of thing.

So what makes it the case that to be a bachelor just is to be an unmarried man? The fact that we use the terms "bachelor" and "unmarried man" to refer to the same sort of thing. — Michael

No, bachelors are unmarried men regardless of what words we used. The terms are synonymous now, which means that no matter what, bachelors are always unmarried men. This persists even if the language changes. It is not as if the way we use the words makes bachelors unmarried men; to be a bachelor simply is to be an unmarried man, period, regardless of what language is used. All the language does is decide that two terms hook up to the same interchangeable group.

You said that the truth of the sentence used on the right-hand side is determined by facts about the extra-linguistic world and not by whatever definitions were stipulated on the left-hand side. So even if the words "horse" and "rabbit" mentioned on the left-hand side mean what they do now, the sentence used on the right-hand is true iff horses are equine animals, and as horses are equine animals then the sentence used on the right-hand side is true. And if it's true then the sentence mentioned on the left-hand side is also true.

No, bachelors are unmarried men regardless of what words we used. — The Great Whatever

I'm saying that to be a bachelor is to be an unmarried man iff we use the words "bachelor" and "unmarried man" to talk about the same thing.

I'm not saying that those people who are bachelors are unmarried men iff we use the words "bachelor" and "unmarried man" to talk about the same thing.

You seem to think I'm saying the latter, but I'm not. I'm saying the former, which is different.

I'm saying that to be a bachelor is to be an unmarried man iff we use the words "bachelor" and "unmarried man" to talk about the same thing. — Michael

Nope. To be a bachelor is to be an unmarried man, period. In Rome, unmarried men were already bachelors, even though the terms were not used.

I'm not saying that those people who are bachelors are unmarried men iff we use the words "bachelor" and "unmarried man" to talk about the same thing.

You seem to think I'm saying the latter. — Michael

Explain to me how this differs from what you just said above. It seems to me you are just asserting then denying the same thing.

The sentence "to be X is to be Y" is equivalent to the sentence "'X' means 'Y'".

The sentence "Xs are Ys" is equivalent to the sentence "those things referred to by 'X' are those things referred to by 'Y'".

The sentence "to be X is to be Y" is equivalent to the sentence "'X' means 'Y'". — Michael

No, it isn't. To show this, it suffices to show that one can be true, while the other false.

Suppose that 'horse' meant 'rabbit.' Then to be a horse would not be to be a rabbit (which is absurd). To be a horse would still be to be a certain ind of animal, the same kind as before.

Suppose that 'horse' meant 'rabbit.' Then to be a horse would not be to be a rabbit (which is absurd). — The Great Whatever

The sentence mentioned is in the same language as the sentence used.

To be a horse would still be to be a certain ind of animal, the same kind as before.

If we change the meaning of "horse" then what it means to be a horse (in the updated language) is different to what it meant to be a horse (in the archaic language).

The fact that we use the terms "bachelor" and "unmarried man" to refer to the same sort of thing. — Michael

And the thing being referred to is non-linguistic. Tying this back to the Chinese Room argument, Searle's contention was that correctly outputting the right word in a given situation is not meaningful, because meaning is in the reference (to horses, rabbits, unmarried men). Meaning is about something, not when to use a symbol.

Consider that it's perfectly possible to say the right word in a conversation without knowing what it means. A person can fake knowing what a word means. So can a machine.

How does reference work? What sort of mechanism is required for words to refer to things? Can computers emulate that mechanism when using words?

If they don't, then why are talking about horses being equine animals, regardless of whether we decide to use the word "horse" differently at some future date?

What?

Just to be clear, what you're arguing is that meaning has nothing whatsoever to do with things themselves. Before there was any words for horses, there was no horse meaning, although those animals still existed. And if we decided to change all our horse language to talk about rabbits instead, then there would no longer be any horse meaning.

Although, there would still be horses, just not as we understand. Those animals would be incomprehensible to us.

If we change the meaning of "horse" then what it means to be a horse (in the updated language) is different to what it meant to be a horse (in the archaic language). — Michael

No. To be a horse is to be a certain kind of animal, regardless of the language. You cannot change what it is to be a horse by changing what you use 'horse' to refer to. If you could, then rabbits would become horses because you called them 'horse,' but they do not become horses, they remain rabbits. And you cannot say 'I don't mean a biological transformation...' because that is precisely what would be required. A rabbit could not change into a horse without changing biologically. That is, it could not change into a horse without changing into a horse.

Do you accept that to be un caballo is to be a horse?