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.