The "this sentence" is a recursive reference. — Michael

OK. You don't mean "recursive". You mean "self-referential". In that case, sure, if the sentence is allowed to claim of itself that it is to be understood in accordance with the linguistic stipulations stated in the antecedent, then, it is true. But it is then equivalent to the following:

(1) If "horses" and "rabbits" are synonymous in some language (that has the same syntax and verbs as English), then, in that language, "horses are rabbits" expresses a true claim.

If you would always say it that way that wouldn't invite any equivocation. But I am usure what philosophical lesson could be drawn from this trivial claim.

Yes, "self-referential". Thanks.

Apply the logic to English, where English is both mentioned and used. If "horses" and "equine animals" are synonymous then "horses are equine animals" is true. If "horses are equine animals" is true then horses are equine animals. Therefore if "horses" and "equine animals" are synonymous then horses are equine animals.

Now inject some Wittgenstein. If we use the words "horses" and "equine animals" in the same way then "horses" and "equine animals" are synonymous. Therefore if we use the words "horses" and "equine animals" in the same way then horses are equine animals.

This is what I've been trying to say. The Great Whatever doesn't like it.

If I say that "horse" denotes having properties A, B, and C and if I say that this animal is a horse then I am saying that this animal has properties A, B, and C. — Michael

If you say that an animal is a horse, you are saying that it has properties A, B, and C, regardless of what words you use to say that it is a horse.

Your confusion is that you think that to say something is a horse is to actually use the word 'horse,' but this is not so. Some uses of 'horse' cannot be used to call something a horse, as when the language is different; and many instances of calling something a horse do not use the word 'horse' either, as when 'caballo' is used instead.

To call something a horse is not to use the word 'horse' to refer to it, except accidentally in cases where these two things coincide, as they do in English. So your conditional is pointless: to call something a horse is to say that it has such properties regardless of the language, and so your point is not made: it in no way depends on what you say 'horse' means, what properties you say something has if you call it a horse.

The Great Whatever accepts the first premise, the T-schema shows the second premise, and so the conclusion follows. — Michael

The T-schema is false, at least as you interpret it, as I have repeatedly shown you.

You've already accepted my argument. When you agreed that to be un caballo is to be a horse you accepted to be a rabbit is to be a horse. Your continued rejection of this stems from a continued equivocation of "rabbit" as it means in English and "rabbit" as it means in my New English.

And I have shown you how a rejection of it leads to incoherence. X is Y but "X is Y" is false (where both the sentence used and the sentence mentioned are in the same language)? It's a contradiction. Assertions implicitly assert their own truth, and so to say that X is Y is to say that "X is Y" is true, and vice versa.

We've already been over this, though. Your argument doesn't work and depends on an equivocation because arguments should be good whatever language they're presented in; if you translate your argument back to English, it should be the same argument; and the result will either be a tautology, not a statement of the dependence of what it means to be a certain kind of animal on language, or unsound.

This is not a contradiction. Suppose for example that in a counterfactual situation, "horses are rabbits" means the sky is blue. Then in that situation, if "horses are rabbits" is true (and thus the sky is blue), it is nonetheless not the case that horses are rabbits, which is nonsense anyhow; it is merely the case that the sky is blue.

Get it?

Suppose for example that in a counterfactual situation, "horses are rabbits" means the sky is blue. Then in that situation, if "horses are rabbits" is true (and thus the sky is blue), it is nonetheless not the case that horses are rabbits, which is nonsense anyhow; it is merely the case that the sky is blue. — The Great Whatever

In that situation if "horses are rabbits" is true then horses are rabbits (where the language of the sentence mentioned is the language of the sentence used).

You're still equivocating by considering the sentence used to be in a language where "horses are rabbits" isn't true.

Also, statements don't implicitly state their own truth; statements are about things, not about themselves, clearly. When I say, "the sky is blue," I say that the sky is blue; I do not say that "the sky is blue" is true. These conditions might correspond when accidentally language is such that the sentence means the sky is blue, but counterfactually they come apart. Again, these are all use-mention errors. You confuse talking about things with talking about words.

In that situation if "horses are rabbits" is true then horses are rabbits (where the language of the sentence mentioned is the language of the sentence used). — Michael

No, they are not; horses can't be rabbits, that's nonsense. What that sentence's truth means is that in that situation, the sky is blue. It means nothing about horses or rabbits at all, since in that situation "horse" does not refer to horses, and "rabbit" does not refer to rabbits, since ex hypothesi the words mean something else.

(where the language of the sentence mentioned is the language of the sentence used). — Michael

Then translate the argument back into English; it should still be the same argument, and therefore just as good as it was before. Why do you insist on having to use a made-up language in order for your argument to make sense? I am trying ot show you that the reason you do this is because the argument does not make sense, and rests on an equivocation. If you translate the argument back again, you will see this; translation does not affect the soundness of arguments.

Clearly this discussion is never going to get anywhere. I'm calling it a day.

Read the Wiki article on the use-mention distinction. It will clear things up.

I've already addressed that. The use-mention error is when you say that rabbits is 7 letters long.

A use-mention error is whenever you confuse the use of words with the mention of words; the use of words typically refers to thing other than themselves, while you seem to believe that the use of words refer back to themselves, as if the use were a mention. Thus you say things like:

In that situation if "horses are rabbits" is true then horses are rabbits

Thinking that a true sentence that mentions "horses are rabbits," i.e. "in that situation, 'horses are rabbits' is true" (which is true) is the same as a use of that bit of language, i.e. "horses are rabbits in that situation," which is obviously false (horses can't be rabbits; any six year old can tell you this).

And you say things like:

Assertions implicitly assert their own truth, and so to say that X is Y is to say that "X is Y" is true, and vice versa.

Confusing the mention of a piece of language in order to predicate something about it, with a use of that very same piece of language.

These mistakes are impossible to make if the use-mention distinction is understood.

Apply the logic to English, where English is both mentioned and used. If "horses" and "equine animals" are synonymous then "horses are equine animals" is true. If "horses are equine animals" is true then horses are equine animals. Therefore if "horses" and "equine animals" are synonymous then horses are equine animals. — Michael

Your conditional seems to run the wrong way. It is because we know that (and only as long as we know that) horses are equine animals (assuming "are" here signifies necessary identity of extension) that the expressions designating them are synonymous. It's not the other way around. If an expression is introduced in the language as synonymous to another expression that already has a referent, then one will be able to use both expressions to make (trivial) identity claims. That's because this specific way of introducing the new word into the language (as synonymous to another one) insures that it has the same Fregean sense as the old one. But, generally, if two words that are in fact co-referential have different Fregean senses, then the fact that they are indeed co-referential is something that might need to be verified empirically; and this will not ensure synonymy unless the knowledge of the identity becomes widespread in the linguistic community and this knowledge would also be taken to be a criterion for understanding both expressions.

Now inject some Wittgenstein. If we use the words "horses" and "equine animals" in the same way then "horses" and "equine animals" are synonymous. Therefore if we use the words "horses" and "equine animals" in the same way then horses are equine animals.

If you mean "using in the same way" to imply that referents are identical then in order to know that "horse" and "equine animals" are indeed used in the same way by us, in the case where we already know how to use them, would require that we check that any horse necessarily is an equine animal and vice versa.

Your conditional seems to run the wrong way. — Pierre-Normand

Which part? You agreed with 'If "horses" and "equine animals" are synonymous then "horses are equine animals" is true' in your previous post and 'If "horses are equine animals" is true then horses are equine animals' is the T-schema, which you accept. The conclusion 'therefore if "horses" and "equine animals" are synonymous then horses are equine animals' simply applies the transitive relation.

If you mean "using in the same way" to imply that referents are identical then in order to know that "horse" and "equine animals" are indeed used in the same way by us, in the case where we already know how to use them, would require that we check that any horse necessarily is an equine animal and vice versa.

We need to know that the things we call "horses" are the things we call "equine animals". Which is to say that we need to know that we use the words "horses" and "equine animals" to talk about the same thing. And what does talking about the same thing consist of? What's the metaphysics behind talking about the same thing? I'm loathe to any interpretation that claims there's more to talking about things than behaviour, intention, and the empirical contexts that influence and measure them. How can anything else become a part of language, meaning, and understanding? This was Dummett's point.

Which part? You agreed with 'If "horses" and "equine animals" are synonymous then "horses are equine animals" is true' in your previous post and 'If "horses are equine animals" is true then horses are equine animals' is the T-schema, which you accept. The conclusion 'therefore if "horses" and "equine animals" are synonymous then horses are equine animals' simply applies the transitive relation. — Michael

You are reading the T-shema in the wrong direction (from left to right rather than right to left) because the T-shema arises in the context of a truth theory that derives truth conditions for sentences of the object-language (mentioned in the left hand-side), and states those truth conditions in the meta-language used by the theorist -- in our case, English. Hence the meanings of the terms used on the right hand side of the biconditional are assumed to be their ordinary meanings in English. What is allowed to vary, in a range of counterfactual circumstances, isn't the meanings of the object-language sentences mentioned on the left-hand side, but rather the worldly circumstances in which their truth values are evaluated.

For instance the (homophonic) T-shema:

(1) "Snow is white" is true iff snow is white

just like the T-shema (stated in French):

(2) "Snow is white" est vrai ssi la neige est blanche

both state exactly the same thing, e.g., that the object-language (i.e. English) sentence "snow is white" is evaluated true in circumstances where snow is white and is evaluated false in (counterfactual) circumstances where snow isn't white. The T-shema is never concerned with counterfactual circumstances where the meanings of the words (of either the object- or meta-language) would be allowed to vary. On the contrary, the meanings of the terms of the meta-language are assumed to be understood and the meanings of the terms of the object-language are assigned with the use of the meta-language. (Those atomic meanings assignments to individual words actually are stated in the axioms of the Tarskian truth theory, while the T-shemas are theorems that are recursively deduced on the basis of those axioms.)

We need to know that the things we call "horses" are the things we call "equine animals". Which is to say that we need to know that we use the words "horses" and "equine animals" to talk about the same thing. And what does talking about the same thing consist of? What's the metaphysics behind talking about the same thing? I'm loathe to any interpretation that claims there's more to talking about things than behaviour, intention, and the empirical contexts that influence and measure them. How can anything else become a part of language, meaning, and understanding? This was Dummett's point.

I agree with everything in this paragraph of yours.

The example I gave didn't use a counterfactual meaning. It used ordinary English. If "horses are equine animals" is true then horses are equine animals.

Even then, that I can state the T-schema in a language other than English, e.g. French, is that I can state the T-schema in a language other than English, e.g. New English.

Also, the T-schema is biconditional so it can be read either way. We can say that "snow is white" is true iff snow is white or we can say that snow is white iff "snow is white" is true. It's an iff, not just an if.

The example I gave didn't use a counterfactual meaning. It used ordinary English. If "horses are equine animals" is true then horses are equine animals. — Michael

In that case your example doesn't have anything to do with the T-shemas that occur in a Tarskian truth theory, and so it's unclear why you attempted to rely on this notion. In the context of such a theory, a T-shema states general truth conditions for a sentence expressed in the object-language and hence has the force of a subjunctive conditional where the truth value of the antecedent is defined as true or false in all possible circumstances, accordingly, whether the condition stated in the consequent is satisfied or not in those circumstances.

Even then, that I can state the T-schema in a language other than English, e.g. French, is that I can state the T-schema in a language other than English, e.g. New English.

You can express the T-shema (and the whole truth theory this shema is derived from) in whatever language you like, including "New English". But such a T-shema tells you nothing about the meanings of the words used on the right-hand side of the shema. Those meanings are assumed to be understood by the theorist who uses the meta-language to state the truth conditions of the sentences mentioned on the left-hand side of the shema.

Also, the T-schema is biconditional so it can be read either way. We can say that "snow is white" is true iff snow is white or we can say that snow is white iff "snow is white" is true. It's an iff, not just an if.

The reason why it's a biconditional simply is because if the T-shema were rather a simple conditional such as:

(1) "The cat is on the mat" is true if the cat is on the mat,

then this would leave the truth value of "the cat is on the mat" undetermined in all cases where the cat isn't on the mat. But we want to stipulate that "the cat is on the mat" is false when the cat isn't on the mat; hence the biconditional. Tarski's intention never was to imply that truth values of object-language sentences determine what can be truly be said in the meta-language.

The reason why it's a biconditional simply is because if the T-shema were rather a simple conditional such as:

(1) "The cat is on the mat" is true if the cat is on the mat,

then this would leave the truth value of "the cat is on the mat" undetermined in all cases where the cat isn't on the mat. But we want to stipulate that "the cat is on the mat" is false when the cat isn't on the mat; hence the biconditional. Tarski's intention never was to imply that truth values of object-language sentences determine what can be truly be said in the meta-language. — Pierre-Normand

It might not have been his intention but the logic of a biconditional is such that it can be read in either direction.

In that case your example doesn't have anything to do with the T-shemas that occur in a Tarskian truth theory, and so it's unclear why you attempted to rely on this notion. In the context of such a theory, a T-shema states general truth conditions for a sentence expressed in the object-language and hence has the force of a subjunctive conditional where the truth value of the antecedent is defined as true or false in all possible circumstances, accordingly, whether the condition stated in the consequent is satisfied or not in those circumstances.

I'm not sure how this makes a difference. You accept that if "X" and "Y" are synonymous then "X is Y" is true and you accept that if "X is Y" is true then X is Y. So it's a straightforward transitive relation to conclude that if "X" and "Y" are synonymous then X is Y. If the premises are true and the conclusion is a valid derivation then the argument is sound.

It might not have been his intention but the logic of a biconditional is such that it can be read in either direction. — Michael

As I explained, just because the connective "if and only if" is used doesn't entail that the conditionals used signify material implications rather than subjunctive conditionals. In Tarski's case, it's the latter that's signified since the circumstances where the antecedent is evaluated range over all possible circumstances (and not just actual circumstances) where this mentioned string of words might be used. Both the "if" and the "only if" signify subjunctive conditionals, and both of those must be read from right to left, since we want the meaning and truth value of "the cat is on the mat" to be determined in all circumstances including circumstances where the cat isn't on the mat.

For instance, the T-shema instanciation:

(1a) "The cat is on the mat" is true iff (i.e. in all cases and only those cases where) the cat is on the mat

is equivalent to the conjunction:

(1b) "The cat is on the mat" is true if the cat is on the mat and "The cat is on the mat" is false if the cat isn't on the mat.

Those all are subjunctive conditionals and they are all meant to be read from right to left; that is, the meanings of the words used on the right hand side are held fixed for purpose of stating unvarying truth conditions meant to apply in the whole range of possible circumstances where the truth of the mentioned sentence (on the left-hand side) is to be stipulated.

This is why use of a biconditional is needed. But it doesn't really matter. You don't need to change the meaning of Tarski's T-shema in order justify your own use of it in a different context; and I think I now have a better grasp of what you are driving at.

I'm not sure how this makes a difference. You accept that if "X" and "Y" are synonymous then "X is Y" is true and you accept that if "X is Y" is true then X is Y. So it's a straightforward transitive relation to conclude that if "X" and "Y" are synonymous then X is Y. If the premises are true and the conclusion is a valid derivation then the argument is sound. — Michael

Yes, if, in fact (i.e. in the actual world) "X" and "Y" are synonymous, and hence have the same referent (Bedeutung) and the same Fregean sense (i.e. they have the same use in the language) then it is also true that X is Y. Hence you can say that:

(1) If "X" and "Y" are synonymous then X is Y

But this must be understood as a material implication, and not a subjunctive conditional. It says that if the antecedent is true, in the actual world, then so is the consequent. It doesn't say anything about counterfactual circumstances. (Though it might be construed as a subjunctive conditional where the antecedent ranges over epistemically possible circumstances rather than alethically possible circumstances; this would make sense if we don't actually know whether, in the actual world, the antecedent it true; that is, s/he who makes the statement doesn't know what either "X" or "Y" mean).

So, this sensible reading would seem to be sufficient to support your point that meaning is use but need no land you in a pickle where you seem committed to infer:

(2) If "X" and "Y" were (counterfactually) synonymous then X and Y would be numerically identical (even though they actually aren't numerically identical).

which is either a misuse of language or expresses a metaphysical impossibility due to the necessity of identity (argued for by Ruth Barcan Marcus and Saul Kripke). But you really don't need that in order to convey your main point, it seems to me.

For instance, the T-shema instanciation:

(1a) "The cat is on the mat" is true iff (i.e. in all cases and only those cases where) the cat is on the mat

is equivalent to the conjunction:

(1b) "The cat is on the mat" is true if the cat is on the mat and "The cat is on the mat" is false if the cat isn't on the mat. — Pierre-Normand

1b) is:

(C → P) ∧ (¬C → ¬P)

Using transposition this gives us:

(C → P) ∧ (P → C)

Which is material equivalence.

If "P" means "man" and if you are a man then you are a P.

What's wrong with this? — Michael

Nothing. I take it that there are certain things implicit in that syllogism, so that it can be reformulated as follows:

If "P" means "man" in language L, and I am a man, then I am a P in L.

If "P" is replaced with "rabbit", then the argument is still sound.

Of course, I am not a rabbit (in accordance with the English language). But if the English language were to change such that the current meaning of "rabbit" became obsolete, and if it also gained a new meaning equivalent to that of the current meaning of "man", and if I am still a man at that time, then it would be correct at that time for me to state in the English language of that time that I am a rabbit.

It should go without saying that it does not follow from the argument in the paragraph directly above that by making that statement, I would be implying that I am a small mammal in the family Leporidae.

I would not have become a rabbit. I was a man before, and would remain a man. It'd also be correct at that time to state that I was a rabbit before, and am a rabbit now. That's because the meaning of "rabbit" at that time wouldn't cease to apply to past times when it wasn't used in that way. Otherwise, if you apply that rule in general, you end up with all sorts of absurd logical consequences, like that two homosexuals weren't gay before the word "gay" was used to mean homosexual. On the contrary, they were gay on account of their homosexuality.

1b) is:

(C → P) ∧ (¬C → ¬P)

Using transposition this gives us:

(C → P) ∧ (P → C)

Which is material equivalence. — Michael

Only if you insist on reading "→" to signify material implication. And this is a rather bad misconstrual of the significance of the T-shema instantiation, as I have explained. But you had suggested that the biconditional form shows that the correct reading is material implication rather than subjunctive conditional. This is a non sequitur since the fact that the statement can be written "(C → P) ∧ (¬C → ¬P)" or "(C → P) ∧ (P → C)" tells you nothing whatsoever about the significance of "→". Instead, you have to reflect a little about the pragmatic significance of the shema in the context of the truth theory it is pulled from. It is this pragmatic significance (i.e. how Tarski's truth theory is meant to be used) that recommends the subjunctive conditional interpretation, as I have explained.

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[...] — The Great Whatever

Yes, I agree that that's a valid reductio ad absurdum, and it seems to me that @Michael must either revise his position or bite a bullet that makes his position implausible.

However, one could avoid your above criticism if one commits to an altered version of the claim:

For any sentence "P", if P, then "P" is true for all cases in which "P" can be formed; and for all cases in which "P" can't be formed, then "P" would be true if it was formed.

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. — The Great Whatever

And, again, to avoid the above, one could revise one's commitment to account for such circumstances. In this case, one could commit to the claim that whether a sentence is true or not depends on the way that it is - or would be - used in the the relevant circumstances. Then one can accept that the universe existed before language existed. At that time, "The universe exists" wouldn't be true, but it would be true if the aforementioned sentence was formed, and if the words of which it consists were used in the relevant way.

However, abandoning the standard formulation might have unintended logical consequences that I haven't considered.

For any sentence "P", if P, then "P" is true for all cases in which "P" can be formed; and for all cases in which "P" can't be formed, then "P" would be true if it was formed. — Sapientia

You don't actually have to tie up the truth of an assertion, or of the linguistic expressions of a thought (that may have a force different than that of assertion or belief) to the circumstances that hold at the time of the utterance. One can equally say yesterday, or today, or tomorrow, in different manners, that Smokey the cat was on the mat yesterday at 11 o'clock. This very same thought would have been expressed yesterday with the situational sentence "Smokey the cat was (or is, or will be) on the mat today at 11 o'clock" or expressed the day before with the situational sentence "Smokey the cat is going to be on the mat tomorrow at 11 o'clock". This whole system of situational sentences enables one to express the same thought, with the same truth conditions, at different times, while making use of the time of elocution, in addition to the form of the speech act used, to determine the temporal thought being expressed.

Hence, one could say that, e.g.:

(1) "There were/are/will be triceratops roaming the Earth" is true iff there were/are/will be triceratops roaming the Earth.

In this case, "were/are/will be" signals the availability of a system of situatonal sentences. This means that the sentence "There are triceratops roaming the Earth" could (conceivably) have been used to express a truth 68 million years ago. But, more importantly, it also means that whatever though would have been expressed back then in that way is the very same thought that we can express now with the sentence "There were triceratops roaming the Earth 68 million years ago". Hence, the statement of the truth conditions of (the thought expressible by) a sentence doesn't require that there actually be anyone able to utter the statement at the time when its truth value is being evaluated, since we still are able to evaluate the truth of the very same thought (concerning past events) as expressed now with the use of a situational sentence that is part of the very same unitary system that allows the expression of this thought at any time.

(This is further discussed in Gareth Evans' The Varieties of Reference, under the heading of "dynamic thoughts" and in Sebastian Rödl's Categories of the Temporal, from whom I borrow the phrase "situational sentence")

You don't actually have to tie up the truth of an assertion, or of the linguistic expressions of a thought (that may have a force different than that of assertion or belief) to the circumstances that hold at the time of the utterance. — Pierre-Normand

Don't you? But if you don't, then that'll have logical consequences which might be unacceptable.

One can equally say yesterday, or today, or tomorrow, in different manners, that Smokey the cat was on the mat yesterday at 11 o'clock. This very same thought would have been expressed yesterday with the situational sentence "Smokey the cat was (or is, or will be) on the mat today at 11 o'clock" or expressed the day before with the situational sentence "Smokey the cat is going to be on the mat tomorrow at 11 o'clock". This whole system of situational sentences enables one to express the same thought, with the same truth conditions, at different times, while making use of the time of elocution, in addition to the form of the speech act used, to determine the temporal thought being expressed. — Pierre-Normand

But it's not the very same thought, is it? Nor is it saying the same thing in different manners; it's saying different things in different manners. None of the thoughts, nor the sentences to which they respectively correspond, are equivalent to each other - despite them all referring to the same event (or potential event, in regard to the future).

(1) "There were/are/will be Triceratops roaming the Earth" is true iff there were/are/will be Triceratops roaming the Earth.

In this case, "were/are/will be" signals the availability of a system of situatonal sentences. This means that the sentence "There are Triceratops roaming the Earth" could (conceivably) have been used to express a truth 68 million years ago. But, more importantly, it also means that whatever thought would have been expressed back then in that way is the very same thought that we can express now with the sentence "There were Triceratops roaming the Earth 68 million years ago". Hence, the statement of the truth conditions of (the thought expressible by) a sentence doesn't require that there actually be anyone able to utter the statement at the time when its truth value is being evaluated, since we still are able to evaluate the truth of the very same thought (concerning past events) as expressed now with the use of a situational sentence that is part of the very same unitary system that allows the expression of this thought at any time. — Pierre-Normand

This part of your post made more sense to me. So, to avoid TGW's criticism, you're saying that at a time before sentences such as "There are Triceratops roaming the Earth" could have been expressed (given that there was no one there to express such a sentence), but in which there would in fact have been Triceratops roaming the Earth, we can use "were/are/will be" in the relevant sentence to mean that there could conceivably have been someone there to express such a sentence (despite there not actually having been anyone to do so), and, by implication, such a sentence would have been true at the time?

If that's a better way of doing it then my suggestion, then great.

I am using "thought" in the same way Frege is, to signify what is thought, which is the content of an assertion expressing it. What is thought -- the content of a mental act -- can also be questioned, hoped for, feared, hypothesized, etc., and in all cases be the same thought, in that sense. Hence if you are thinking that I am 6 feet tall and I am thinking that I am 6 feet tall, we are thinking the same thought. I would be expressing this thought with the sentence "I am six feet tall", while you would express it, while addressing me, with the sentence "You are six feet tall". Those two statements make use of to different speech act forms, since one of them uses the indexical "I" while the other one uses the indexical "you". But they can express the same thought in a suitable context (that is, as uttered by two different individuals suitably related). Likewise, my statement "the grass is wet over there" could, in some context, express the same thought that you would express with the statement "the grass is wet over here". I could also express the same thought myself on two separate occasions with those two different speech act forms just through moving between the two places. The later statement ("it's wet over here") can rationally bear -- i.e. confirm -- the previous statement ("it's wet over there") just because both statement express the same thought (assuming only that they are understood to encompass the same coarsely discriminated 'present' time).

Thoughts (or judgments) that are thus kept track of through displacement in space, or through keeping track of the passage of time, are called dynamic thoughts by Gareth Evans. To be able to entertain such dynamic thoughts, and master the system of situational sentences that relate their different forms of expressions at different times (and different locations) is a condition for being able to entertain them at all. For else, one would never be able re-express the very same empirical thought at two different occasions, and one wouldn't even be able to re-affirm, or contradict, or empirically verify, or infirm, an empirical thought that one had previously entertained.