I think a distinction needs to be made between these two claims:

1. "p" is true iff p
2. "'p' is true" means "p"


Now Davidson pointed out that if you have a true T-sentence such as

1. "S" is true iff p

then you have in p, in effect, the meaning of S. — Banno

The problem here of course is that this doesn't really give you the meaning of S. You might say that "S" is true iff p, and replicate "S" with p, but that is just to repeat S, not to give it's meaning. You might make up something else, like "S" is true if q, but that would just be a subjective opinion of the meaning of "S". Or you might propose a justified meaning of "S", but that would just give you a justified meaning of "S", not the true meaning of "S". So the T-sentence really gives you absolutely nothing.

The imagination is the sort of thing that changes -- and so it's not a basis for understanding logic, given that logic is more stable than the imagination.

I'd have said some things once unimaginable are imaginable to me now. For instance, I thought classical and quantum mechanics conflicted at one point. I couldn't imagine that these could both be true! It was impossible!

Now, I'd say, I can imagine that. And I can tell persons who can't imagine it what finally clicked for me.

So I'd say that what you're calling "logic", I'd call "giving reasons to appeal to reason", or something like that. These arguments are important. I still reference Kant and Aristotle and all them. But there are times when what appears to be contradictory states of affairs to our imagination turns out to be an inability to imagine the right way of connecting what at first appeared contradictory.

Hence why imagination, though it is the capacity we use in thinking about logic, isn't the same as logic.

It isn't clear what this means. What's a material equivalence? Why not just an equivalence? — Tate

Material equivalence is usually thought of as obtaining between two propositions, or not. If two propositions have the same truth values on every row of a truth tables. It's another way of saying "correspondence".

The imagination is the sort of thing that changes -- and so it's not a basis for understanding logic, given that logic is more stable than the imagination.

I'd have said some things once unimaginable are imaginable to me now. For instance, I thought classical and quantum mechanics conflicted at one point. I couldn't imagine that these could both be true! It was impossible! — Moliere

I think there are things which are simply unimaginable as I said, and it is those things I am referring to, not things which change; which we can come to imagine with more practice or whatever. Think of Kant's pure forms of intuition: we cannot imagine an object without spatial dimensions, or without persistence in time, or without form, or without constitution, and so on,

Your reference to QM is a good case in point: it seems contradictory to say that something could be both a wave and a particle simply because the way we imagine each of these to be seems to make them incompatible. I think it was Feynman who said "I think I can safely say that no one understands quantum mechanics". I think it's obvious he means that no one can imagine what is going on, not that no one can understand the maths.

Or take the idea in relativity theory that mass warps the fabric of spacetime: no one can imagine, in the sense of visualize, a three dimensional space warping (into a fourth dimension), so to get some visual purchase on the idea a model of a two dimensional surface warping (into the third dimension) is offered.

I didn't have my sub in mind, but then no doubt it's true that all subs have holes in them, even if they haven't appeared yet.

Material equivalence is usually thought of as obtaining between two propositions, or not. If two propositions have the same truth values on every row of a truth tables. It's another way of saying "correspondence". — Janus

That's not truth deflation and most definitely not correspondence theory.

There is a material equivalence between "snow is white" and the fact that snow is white. We can also say there is a correspondence.

These supposed counterexamples were given:

"But there are cases where the correspondence theory becomes opaque. It is not at all clear what the "empirical facts of the world" are that make the propositions "four is twice two", "no married men are bachelors " or "this note is worth ten dollars" true. Yet the appropriate T-sentence will still hold."

I don't think the correspondence account (I dislike "theory") is opaque in these cases at all. "Four is twice two" can easily be demonstrated empirically with apples; in fact it is by using objects that children are taught to count. It is a fact of our world that married men are not counted as batchelors, and on investigation it would be found that bachelors do not possess valid marriage certificates, and have not participated in the ceremony of marriage. That a note is worth ten dollars is a fact easily verified in any store in the world. It just takes a little imagination to see that correspondence does hold, and that in fact we have no other viable account of truth.

There is a material equivalence between "snow is white" and the fact that snow is white. We can also say there is a correspondence. — Janus

There aren't actually two propositions there. It's one sentence. Have you modified the idea of material equivalence?

There is a sentence which expresses the proposition that snow is white and there is the fact that snow is white. So the two are materially equivalent, even if saying that stretches the normal usage of the term to refer to two propositions. I just did a quick search and found this:

"As we saw in the last section, two different symbolic sentences can translate the same English sentence. In the last section I claimed that “~S ⊃ R” and “S v R” are equivalent. More precisely, they are equivalent ways of capturing the truth-functional relationship between propositions. Two propositions are materially equivalent if and only if they have the same truth value for every assignment of truth values to the atomic propositions. That is, they have the same truth values on every row of a truth table. The truth table below demonstrates that “~S ⊃ R” and “S v R” are materially equivalent."

From here

I didn't introduce the term into the discussion, but it seem to me that the term is to all intents synonymous with "correspondence", albeit without the metaphysical baggage that can accompany the latter term.

There is a sentence which expresses the proposition that snow is white and there is the fact that snow is white. — Janus

It appears to be the same proposition. If not, how are they different?

This isn't the T-schema, as I'm sure you're aware.

That's: "Snow is white" is true IFF snow is white.

You've got the proposition that snow is white being materially equivalent to the proposition that snow is white. ?

Sheet-as-sheet to me indicates naming and descriptive practices accompanying the seeing. This eliminates language less seeing of the sheet, which - of course - is a problem.
— creativesoul

Is it? — Moliere

Well, sure it is! Some language less creatures can see a sheet. I would not say that they see a sheet-as-sheet. I don't think you would either.

Perhaps a better tact, though: if truth is more general than linguistic -- say it is a correspondence between some animal belief and facts or reality, construing belief broadly to indicate that it could be linguistic or not so as to make explicit that we're interested in this -- then we are the types of creatures that rely upon linguistic truth, and only by understanding this kind of truth would we even be able to make statements more general about this bigger-picture truth. — Moliere

Not exactly the wording I would use, but I think I agree with the general thrust/idea. I would only note that we not only rely upon notions of truth(linguistic truth), but...

...we also rely upon correspondence long before being able to talk about it. <--------that last bit, of course, cannot be arrived at without complex language use capable of thinking about our own thought and belief as a subject matter in its own right; which is the point you're making if I understand you correctly. If I do, then we agree on that.

Nice comparison/contrast regarding correspondence and T sentences.

:point:

@Banno

You've got the proposition that snow is white being materially equivalent to the proposition that snow is white. ? — Tate

You can't do that.

You can't do that. — Tate

I can't do what?

I suggest you and @Janus work out what you're doing between you and get back to me.

I can't do what? — Banno

You said deflationary truth is where there's a material equivalence between a true sentence and a fact.

This is not the case. It says there's a material equivalence between "P" is true, and P.

You're just wrong.

we cannot imagine an object without spatial dimensions, or without persistence in time, or without form, or without constitution, and so on, — Janus

Why not? Aren't we doing so right now, through the power of language?

You're just wrong. — Tate

Ok, then. Best if you don't pay any attention to my posts.

Best if you don't pay any attention to my posts. — Banno

Oh dear.

Speaking about something, or conceptualizzing it, are not the same as imagining it. We can conceptualize a dimensionless point, but cannot imagine it.

The fact that snow is white, snow being white, is a fact or state of affairs, not a proposition. What is stated in the sentence "snow is white" is the proposition that snow is white.

The fact that snow is white, snow being white, is a fact or state of affairs, not a proposition. What is stated in the sentence "snow is white" is the proposition that snow is white. — Janus

Material equivalence is just for propositions.

Perhaps a better tact, though: if truth is more general than linguistic -- say it is a correspondence between some animal belief and facts or reality, construing belief broadly to indicate that it could be linguistic or not so as to make explicit that we're interested in this -- then we are the types of creatures that rely upon linguistic truth, and only by understanding this kind of truth would we even be able to make statements more general about this bigger-picture truth. — Moliere

Digging in...

There is no single referent for "linguistic truth". There are several. The only one applicable to language less creatures' belief is correspondence. My twenty-seven-month-old granddaughter knew that "there's nothing in there" was not true, despite her not having a linguistic notion of truth, because she knew what the utterance meant, and knew that there were things in there(the fridge).

That's correspondence understood long before ever learning to how to use the term "truth". Long before becoming aware of her own fallibility, long before skepticism and doubt have fertile enough ground to sprout, long before all that... she already knew when she heard a false claim about the contents of the fridge.

Language less creatures' belief is different though. They cannot know when some statement is false for they do not think, believe, or speak in statements. I'll leave it there for now...

Material equivalence is just for propositions. — Tate

Take it up with Banno; the term was not introduced by me.

Take it up with Banno; the term was not introduced by me — Janus

No.

in fact it is by using objects that children are taught to count. — Janus

I don't agree with this supposed "fact". I was taught how to count by learning an order. We start with the word one, then two, then three, up to ten. A few repetitions and I had the order memorized. It was explained that each number represents a different quantity, but I was not shown those different quantities. I was shown some of the quantities, like one and two, to get the idea of what a quantity was, but that's not how I learned to count. I learned to count by learning the order.

I believe that this is why we readily accept Platonic realism, because when we learn to count in this way, by learning an order, the only objects counted are the numbers. But intuitively we believe that if we are counting, or if we are learning an order, then there must be something real which is counted, or ordered. That is, if one apprehends an order, there must be something which is ordered, and that something is the numbers. Therefore, numbers are real objects, which have an order, Platonic realism.

My twenty-seven-month-old granddaughter knew that "there's nothing in there" was not true, despite her not having a linguistic notion of truth, because she knew what the utterance meant, and knew that there were things in there(the fridge). — creativesoul

Now, these examples are close to home, so I feel a bit unfair criticizing them. But I'd say that there's a difference between knowing and being able to explicate a concept, and that twenty seven months is more than enough time to no longer count as "language-less" -- after all, she knew the words and what they meant and what truth and falsity were, what a participant in a conversation is, identities of participants including her own -- so much already there in the game of truth-telling, and --

"There's nothing in there" is true iff there's nothing in there.

Both are false, and so the "iff" is true. So the T-schema works for your example.

But then, doesn't it bare to reason that if our imaginations cannot image particle-wave duality, yet particle-wave duality is true, that logic isn't based on images? That these are more like heuristic arguments?

Maybe Kant was wrong? But, eh, like I said I'll have to read more before really pursuing this thought. I mostly just wanted to say that the relationship between time and logic isn't some kind of obvious done-deal -- it's not obvious that we should think of time and space as our imaginations depict them.

The granddaughter is not language less. Did you bother to read the entire post?

I did. I figured when you said

The only one applicable to language less creatures' belief is correspondence. — creativesoul

That your example was meant to convey something about someone without language using correspondence, so I thought it important to say that language is part of your example.

But I missed the last sentence. OK, this is a contrast case, not an example. My bad. I was reading it as the example.

Sure, I agree that with a language less creature that they do not speak about truth or falsity or anything like that. Say a wild bird -- they communicate, but it's not with language. Or, perhaps we could say, it's a proto-language, prior to having the ability to represent its own sentences.

Why doesn't everyone just sum up their views of truth in roughly two to three paragraphs. No responses to the summation, just your particular point of view. At least no responses until the summaries are complete.