they make decidedly inadequate subjects of veneration. — Tom Storm

Veneration. Honestly such an appalling idea. Hero worship, God worship, all of it just seems terrible to me.

What if your best self is an exceptionally talented serial killer? — Tom Storm

By “best” I’m also including moral goodness.

I dislike the notion of role models. I've never had any. Aspiring to be like someone else seems to me to show a weakness of character and a lack of self esteem. Better to aspire to be your best self instead.

And, in order to evaluate "better fit" for any given theory of truth, you'd have to understand truth already. So the very act of being able to evaluate correspondence/coherence in particular circumstances means we must already have some understanding of truth that is neither correspondence or coherence — Moliere

The T-schema suffers from the same problem, as I mentioned before.

1. "p" is foo iff p

This is not a theory, or definition, of "foo".

If we want an actual definition of truth then we need some q such that “[is] true” means q, or “‘p’ is true” means q.

For me I'm getting caught up in the notion that it's us who decide what counts as "material object" — Moliere

Your wording is ambiguous and leaves it open to equivocation. We decide that the word "water" refers to this stuff, that the symbol "2" refers to this number, that the letters "H" and "O" in chemistry refer to these elements, but we don't decide that water is H₂O.

Ah, OK. I guess I'm just looking for something a little more universal from a theory of truth, and I see the T-sentence as setting out that universal relationship effectively for all sentences other than the liars -- including sentences like the kettle. — Moliere

The T-schema doesn’t say much and is compatible with more substantial theories of truth, e.g:

“7 + 5 = 12” is true iff 7 + 5 = 12, and

7 + 5 = 12 iff “7 + 5 = 12” follows from the axioms of maths, therefore

“7 + 5 = 12” is true iff “7 + 5 = 12” follows from the axioms of maths

But I should add that I don’t think it’s a given that I’m talking about the correspondence theory. I’m not saying that some sentences correspond to material objects; I’m only saying that some sentences depend on material objects to be true.

As a rough analogy to explain the difference, speech depends on a speaker, but it doesn’t correspond to a speaker.

I'd reject correspondence theory as a universal theory of truth -- since 7 + 5 is 12, and "7 + 5 = 12" is true. — Moliere

So do I. I think coherence is a better fit for formal systems like maths.

That just strikes me as clearly false. I understand the point you're making, but lately on this forum people making that point use the phrase "forms of life" more often than they use "language-games" to try to mitigate its implausibility. — Srap Tasmaner

It does seem to me that people have been taken so completely by Wittgenstein and those like him that they’re being bewitched by language in the opposite direction. Now apparently everything is language.

The kettle itself isn't boiling at all, if we choose to use the general name "kettle" to only refer to the metallic kettle, and not the water inside. It's only because we agree upon what "the kettle" picks out that we can even check the material world in the first place — Moliere

But we still have to check the material world because it is the material world that determines whether or not the sentence is true. All you’re saying is that we decide what the sentence means. The meaning of a sentence isn’t the truth of the sentence. The truth depends on the meaning, but it also depends on the material world.

Unless something is true by definition, “S means p, therefore S is true” is an obvious non sequitur.

But here's a question people might be inclined to answer very differently: if you understand all the T-sentences of a language, do you also understand a world? Or maybe even the world? Either answer is interesting. — Srap Tasmaner

I’d say no. Understanding that “snow is green” iff snow is green and that “snow is white” iff snow is white isn’t understanding that snow is white. For that you have to actually look at the material world/experience it.

Only because we care about truth in relation to the material world, though. English is set up like that — Moliere

Yes, and I’m trying to describe how truth works in the English (or other natural) language. So I don’t understand this response.

So it's not the definitions of words which make it true, as you say, but it's still how we use language that makes a particular sentence true or false — Moliere

It’s not just how we use language. I say “the kettle is boiling”, you say “the kettle is not boiling”. One of us is right and one of us is wrong, and the thing that determines that isn’t me saying one thing and you saying the other (else which of us is right?).

It’s the existence of a material object (or set of material objects if you prefer, or mental phenomena if idealism is correct) and its behaviour that determines which of us is speaking the truth.

Though I imagine that quibbles are very possible since the argument doesn't contain the phrase "linguistic", so the opportunity to put non-linguistic stuff into semantic content still seems available to an opponent. I believe this was the strategy Banno gestured towards later; that it's a category error to think that the non-linguistic stuff is "really" non-linguistic since arbitrary environmental objects can be brought language practice as semantic content. — fdrake

Even if you put non-linguistic stuff/environmental objects into semantic content it is still the case that this non-linguistic stuff/environmental object is a determinant for truth. "The kettle is boiling" being true depends on the existence of the material object referred to by the phrase "the kettle".

I really didn't think that this would be such a controversial point. The world isn't just a conversation we have with each other. The materialist will say that there are material objects that exist and have properties, irrespective of what we say; the idealist will say that there is mental phenomena that occurs and has qualities, irrespective of what we say. That our language "carves up" this stuff isn't that this stuff isn't there, or doesn't factor into a sentence being true.

It's not the case that we just define every sentence in our language and the truth of every sentence follows from those definitions, so it must be that something which isn't our language plays an essential role. That is what my argument tries to show.

So if the same thing decides that two sentences are true, then they are the same sentence - they mean the same thing. — Banno

This is ambiguous.

John being a bachelor determines that "John is not married to Jane" is true and that "John is not married to Jake" is true.

"John is not married to Jane" and "John is not married to Jake" are not the same sentence; they do not mean the same thing.

Yes.

...and...? — Banno

Not sure what more you want. I think I covered it when I said that a) a rigorous account of truth should cash out the consequent of the T-schema, and that b) the truth of a sentence often depends on more than just its meaning; it often depends on a material object, or on a mental phenomenon, etc.

But it says what can be said. — Banno

But not what only can be said. We're not required to just stop at "snow is white" is true iff snow is white. A rigorous account should cash out the consequent of that biconditional.

If you need a metaphysics before you can decide if the kettle is boiling — Banno

I don't. I need a metaphysics to understand that a boiling kettle is a mind-independent material object, or that it's a mental phenomenon, etc.

IS there a way to determine X? — Banno

Well, is there a way to determine which metaphysics is correct? If materialism is correct then the truth of "the kettle is boiling" depends on the existence of a material object; if idealism is correct then the truth of "the kettle is boiling" depends on the existence of a mental phenomenon.

This is why, as I have said many times, that the T-schema doesn't say much. It doesn't answer a question like the above, which is important. We need to cash out the consequent of the biconditional. I made a start at that here:

We've been taking as a starting point "snow is white" is true iff p and then discussing p, whereas I think we should instead take as a starting point snow is white iff q and then discuss q.

Snow is white iff snow appears white, or
Snow is white iff snow reflects all wavelengths of light, or
Snow is white iff snow has a mind-independent sui generis property of whiteness, etc.

We can then bring this back to truth-predication by understanding that if "p" is true iff p and if p iff q then "p" is true iff q.

"Snow is white" is true iff snow appears white, or
"Snow is white" is true iff snow reflects all wavelengths of light, or
"Snow is white" is true iff snow has a mind-independent sui generis property of whiteness, etc.

But not in all cases. — Banno

I was referring to the sentence "the kettle is boiling".

I have mentioned before that I'm not talking about every sentence. Obviously the truth of a sentence like "1 + 1 = 2" does not depend on a material object and its properties. A coherency theory would be more fitting for formal system like maths.

The error I see in what Michael proposes is that he thinks we can talk about the kettle outside of language. He needs a "non-linguistic kettle" to make his account work. — Banno

When I say that kettles are non-linguistic I mean that they are not words or sentences or any other feature of language. I’m addressing those who say that the truth of a sentence is determined by some other sentence, like some kind of coherency theory, which is false in the case of a sentence like “the kettle is boiling”. The truth of the sentence is determined instead by a material object and its properties.

Once we fix the meaning of a sentence such that it refers to that material object and its properties, changes to that material object and its properties change the truth value of that sentence without changing the meaning of that sentence, and so the truth of that sentence depends on more than just its meaning.

Sometimes “it is raining” is true and sometimes “it is not raining” is true. This isn’t explained by us continually revising the terms in our language: it’s explained by events in the material world; events which occur irrespective of language.

It was. Using "normal set theories" like ZF or ZFC was your suggestion, not mine. I was evaluating your proposal from a much more generalized perspective and showing how it's untenable even with a set theory tamed to be "physicalist-friendly"- this was discarded per your call — Kuro

Then you need to be more explicit with your argument. What sort of things are members of your premised set of all that exists? Urelements like apples, in which case we’re not using ZFC, or only sets, in which case it has no relevance to real life where non-sets exist.

What's that got to do with the slingshot? — Banno

That’s my understanding of the slingshot. All it says is that all true sentences refer to the same world, just as all true sentences about the kettle refer to the same kettle. It doesn’t follow from the latter that the kettle is black iff the kettle is metal and so it doesn’t follow from the former that the kettle is black iff snow is white.

But if my understanding of the slingshot is incorrect then I think Tate’s link is a good response. “Clark Kent” refers to Superman but it doesn’t follow from this that if Lois Lane knows that Clark Kent is Clark Kent that she knows that Clark Kent is Superman. Davidson is wrong in asserting that co-referring terms are logically equivalent.

Trouble is you would also have to agree that "snow is white" is true because the kettle is boiling. — Banno

I don’t. Both “the kettle is black” and “the kettle is metal” refer to the same kettle but it doesn’t follow from this that the kettle is black because the kettle is metal.

Then I think the problem is with the wording of the discussion. In ZFC, urelements are not allowed. Everything is a set. But in the real world things exist which aren’t a set, e.g apples. If you had worded this as saying that the universal set in ZFC is impossible then I wouldn’t have even bothered replying. I thought this was talking about more than just pure maths.

The physicalist takes that all that exists is physical. In set theory, the universal set is the set of all that exists. Therefore, per extensionality, these are substitutable salva veritate and, per the axiom, the same. — Kuro

But sets don’t exist if physicalism is true, and so following your reasoning the physicalist cannot define any set. Given that the physicalist does define sets when using set theory, his physicalism plays no role, and so, when using set theory, sets exist and the set of all that physically exists isn’t a universal set (as the universal set includes sets, which don’t physically exist).

Then the mathematical anti-realist can use set theory to define the set of all that physically exists in my cupboard, or all that physically exists in England, or all that physically exists in the one and only universe. None of these are a universal set within ZFC.

So how is it that mathematical anti-realists, like physicalists, can use set theory?

This is an explanation of a relatively simple set-theoretic result, since we've already fixed the set theory we're operating in. I'm quite appalled that it requires this many replies and/or elaborations. — Kuro

The set theory we’re operating on is the one in which sets exist, and so the set of all that physically exists isn’t a universal set.

The universal set is the same as "the set of all that exists". In physicalism, "all that exists" is just physical stuff (though this does not mean "existing" and "being physical" having the same meaning, just that they coextend)

This is contradictory because, as explained to you several times, it would violate the pairing axiom, the foundation axiom as well as Cantor's theorem which I spoke of earlier. — Kuro

We can assume, when doing maths, that sets exist even if sets do not exist. A physicalist, who doesn’t believe that sets exists, can make use of ZFC set theory.

In using ZFC set theory, this physicalist can define the set of all that physically exists. Within ZFC this isn’t contradictory because it isn’t a universal set.

But if physicalism is true then everything that exists in the real world is a member of the set of all that physically exists within ZFC set theory.

The non-existence of the universal set in ZF, ZFC and so on is a well established mathematical theorem in those set theories. — Kuro

I’m not talking about the universal set. I’m talking about the set of all that physically exists. These are not the same thing.

So, in ZFC, why is the set of all that physically exists contradictory?

This "physicalism-constrained set theory" fails — Kuro

I’m not taking about that though. Use normal set theory. The set of all that physically exists is not contradictory. It might not be, within set theory, the set of all that exists, but if physicalism is true then everything that actually exists is a member of the set of all that physically exists.

Anti-realists can pretend that sets exist for the sake of the maths to then talk about everything that actually exists.

The set of all that exists is contradictory. — Kuro

The set of all that physically exists isn’t contradictory (at least with respect to the power set), which is what that argument shows.

No? I'm saying that the non-existence of the set of all that exists is an issue far prior to the philosophy of mathematics (namely because it's an issue provable in mathematics): the existence of the set is contradictory, so both platonists, who are realists about other sets, and nominalists, realists about no sets whatsoever, would agree it doesn't exist. — Kuro

Where’s the contradiction here?

1. The set of all that physically exists is {apple, pear, ...}
2. The power set of this is {{}, {apple}, {pear}, {apple, pear}, ...}
3. No member of the power set physically exists
4. Therefore, the power set is not proof that there are things which physically exist and are not members of the set of all that physically exists — Michael

Your response before was just to say that if physicalism is true then there are no sets.

It is not simply that the material belongs to the national archives, it is that the material contains classified documents. Having them in his personal possession raises national security issues. The fact that he did not protect them from a whole host of people raises national security issues. Is it that you are not able to see why it is of concern, or are you just pretending not to? — Fooloso4

I am not concerned. He was the president of the United States, the commander in chief, and had the unilateral power to do whatever he wanted with those documents, including taking them home. — NOS4A2

"He was legally allowed to do it, therefore there is no national security issue".

That's a fallacious inference.

And he had no legal right to retain them, or to defy the subpoena for their return, after losing the Presidency.

The set itself asserted by that premise doesn't exist. — Kuro

So you're saying that if mathematical anti-realism is true then there is no set of all that exists, because there are no sets? And so your very argument, which uses sets, depends on mathematical realism being true?

The members of the set in (2) physically exist, but the set itself doesn't per physicalism. — Kuro

I'm aware. What is the relevance of that? I'm not saying that the set physically exists. I'm only saying that the power set doesn't prove that some things physically exist which are not in the set of all that physically exists.

In even asserting that the set is anything, like having the property of "containing apple as a member", you get back to existential commitments. — Kuro

Mathematical anti-realists and physicalists are quite capable of doing maths with sets.

Perhaps a clearer example:

1. Physicalism is true (assumption)
2. The set of all that physically exists is {apple, pear, ...}
3. The power set of this is {{}, {apple}, {pear}, {apple, pear}, ...}
4. No member of the power set physically exists
5. Therefore, the power set is not proof that there are things which physically exist and are not members of the set of all that physically exists

(1) entails that no sets exist, including that set in (3) — Kuro

I think there's a difference between saying "there is a set of all that exists" and saying "the set of all that exists, exists". The mathematical anti-realist will assert the former but reject the latter.

the assumption in 5, that the powerset is literally empty — Kuro

I didn't say that it's empty. Similar to the above, there's a difference between saying "the set has members" and saying "the members of this set exist". The mathematical anti-realist will assert the former but reject the latter.

So, the power set isn't empty, but as all of its members are sets, and as sets don't exist, none of its members exist. As such, it doesn't follow from the fact that the power set has more members that there exist things which aren't in the set of all that exists.

As I said before, I think you're equivocating on the word "exists". Being a member of a set isn't the same thing as existing (if physicalism and mathematical anti-realism are true).

If you assume physicalism, the set of all that exists, let alone the set of anything, since sets are not physical objects neither identical to their physical members nor the collection of their physical members (the proof of this is simple: suppose it is the case, then submerge that same set under a further set, which is mathematically non-identical!) — Kuro

I don't understand how this addresses my argument. Can you specify which step you disagree with?

1. Physicalism is true (assumption)
2. Everything that exists is a physical object (from 1)
3. The set of all that exists is the set of all physical objects (from 2)
4. The power set has more members than the set of all that exists
5. No member of the power set exists (from 2)
6. Therefore, that the power set has more members than the set of all that exists does not prove that some things exist which are not in the set of all that exists (from 5)