And yet we obviously cannot know either of those. — Janus

It's not obvious to the anti-realist.

If your only "argument" against anti-realism is that it's "obviously" wrong then it's not an argument, just a denial.

It's not obvious to the anti-realist.

If you're only "argument" against anti-realism is that it's "obviously" wrong then it's not an argument, just a denial. — Michael

If the antirealist says we can know whether or not there is a god or a multiverse then they should be able to give an account of how that would be possible. There is no such account that I know of and absent such an account they are not to be taken seriously.

….isn’t existentialism generally concerned with ethical normativity…. — Wayfarer

At least in part, sure, but moreso I think in opposition to abstract systemic metaphysics, some of which, ironically enough, prioritize the subject’s existence, and investigate aesthetic judgements naturally incorporated in his rationality.

But I’m not all that familiar with the particulars of existentialism as a discipline, so I better quit while I’m ahead.

Agree I’ve lead us off into the long grass

Although that said I still favor constructivism which as a general approach is more characteristic of continental philosophy than Anglo.

Funny. I was going to blame your Zahavi post for my 4-hour sojourn through cloudspace, where I found Intro to Phenomenology. Like a freakin’ bait trail, this leading to that leading to the other, ending up with exposures I wouldn’t have bothered finding on my own and for which, I must say, am the better off for even without agreeing with much of it.

I can do continental constructivism, at least from an epistemological perspective, if not so much from educational psychology.

Oh. And Death of God. It seems some form of qualitative ethical measure of what is best, is owed, seeing as how we killed him. According to Freddie, anyway, who could hardly be considered Anglo or analytic.

A simple account would be to first argue that "'it is raining' is true" means "it is raining", and then to argue that "it is raining" is meaningful only if it describes a verifiable event. It would then seem to follow that "'it is raining' is true but unverifiable" makes no sense. — Michael

But "'it is raining' is true" means that it is raining, not "it is raining".

That looks trivial, but it isn't. A name does not have a truth value. "It is raining" is the name of a proposition.

Why should we hold that "it is raining" is meaningful only if it describes a verifiable event? Why go there when we can say "it is raining" is meaningful iff '"It is raining" is true' can have a truth value?

Correspondence works wonderfully for observations of medium-sized smalls goods, and for that purpose it is a pretty good approximation to truth. But if what we want is a definition of truth that will work in all cases, it's wanting. There are truths for which it is not obvious that there is some verifiable event that makes them true. What verifiable event might you elicit to claim that arithmetic is true? Or that it is true that you enjoy ice cream? Of that 100 cents makes $1? Or even "PV=nRT", which presumably might only be verified by collecting every such instance.

Correspondence is not wrong, just insufficient.

I understand you to be offering these as examples, rather than some position you wish to defend? But substantive theories of truth I take it to have been shown to all be inadequate in various ways. Hence Tarski's work and the subsequent deflationary accounts.

My comments about truth being a single-placed predicate are intended to show that there are uses for assigning truth to sentences outside of our attitudes towards them. I've highlighted these elsewhere -

Surprise
We are sometimes surprised by things that are unexpected. How is this possible if all that is true is already known to be true?

Agreement
Overwhelmingly, you and I agree as to what is true. How is that explainable if all there is to being true is attitudes? How to explain why we share the same attitude?

Error
We sometimes are wrong about how things are. How can this be possible if all that there is to a statement's being true is our attitude towards it?

Now I know we have previously agreed that Kripke's theory is interesting here, so we might cut to that, and ask if it is antirealist.

If the antirealist says we can know whether or not there is a god or a multiverse then they should be able to give an account of how that would be possible. — Janus

That’s not exactly what they’re saying. They’re saying that:

1. If “God exists” is true then it is possible to prove that it is true
2. If “God exists” is false then it is possible to prove that it is false
3. If it is not possible to prove that “God exists” is true and not possible to prove that “God exists” is false then “God exists” is neither true nor false

Dummett’s argument is that the disagreement between the realist and the antirealist concerns the logic of truth. For the realist, every proposition is either true or false. For the anti-realist, some propositions are neither true nor false.

And it’s important to remember that, at least if we accept the premises of Fitch’s paradox, we’re dealing with modal possibility, i.e that if it is not possible to know something then it is necessarily unknown, e.g that in no possible world does anybody know it.

But "'it is raining' is true" means that it is raining, not "it is raining". — Banno

Take these two sentences:

1. “It is raining” is true
2. “It is not raining” is true

According to your reasoning, (1) means that it is raining and (2) means that it is not raining.

It’s not clear what you mean by “means” here. Do you mean “entails”? If so then there are two issues:

The first issue is that when I say “means” I don’t mean “entails”; I mean “is semantically equivalent to”. So, (1) is semantically equivalent to “it is raining” and (2) is semantically equivalent to “it is not raining”.

The second issue is that (1) doesn’t entail that it is raining; rather, (1) being true entails that it is raining. You appear to be mixing up your use and mention.

1. If “God exists” is true then it is possible to prove that it is true
2. If “God exists” is false then it is possible to prove that it is false
3. If it is not possible to prove that “God exists” is true and not possible to prove that “God exists” is false then “God exists” is neither true nor false — Michael

The problem is that no conjecture can be proven to be true or false, so on the antirealist view, assuming you have correctly outlined it, no conjecture could be either true or false.

The problem is that no conjecture can be proven to be true or false, so on the antirealist view, assuming you have correctly outlined it, no conjecture could be either true or false. — Janus

I’m not sure what you mean.

The conjecture “alien life exists on Pluto” can be proven true or false by going to Pluto, looking everywhere for life, and then either finding it or not finding it.

It’s not clear what you mean by “means” here. — Michael

And you think it was clear for you? I was only copying your use:

"'it is raining' is true" means "it is raining" — Michael

We have a choice between dropping meaning and looking to use and dropping meaning and turning to truth. I like it both ways. But not dropping meaning and looking towards verification, as you suggest, and frot he reasons I gave. Nothing to do with "entails". Or entrails.

You appear to be mixing up your use and mention. — Michael

Not I. You appeared to do so, with

"'it is raining' is true" means "it is raining — Michael

...hence my reply. Again, "'it is raining' is true" means it is raining, NOT "'it is raining' is true" means "it is raining". See the mention where there should be a use in the second?

One of us is clearly misunderstanding the other. I’ll try to rephrase what I was saying more clearly:

1. “It is raining” is true
2. It is raining
3. “It is not raining” is true
4. It is not raining

Sentences (1) and (2) mean the same thing.
Sentences (3) and (4) mean the same thing.

This is precisely the deflationary account that you claimed to support above.

Sentences (1) and (2) mean the same thing. — Michael

...I would say no more than: “It is raining” is true≡ it is raining. Nothing here about meaning. I think you introduced "meaning" into the discussion - perhaps not - but either way, it remains unclear how this helps the topic, or relates to it any more than bringing in intension.

I'm not sure what it is you are arguing for, if indeed you have a thesis that is being touted. Or what it is you are objecting to, if you are making an objection.

Right, I had in mind conjectures like 'QM correctly models reality'. Or 'reality is mind-dependent' or 'reality is mind-independent'.

As to your example finding life on Pluto would prove there is life on Pluto, but finding no life on Pluto cannot prove there is no life on Pluto.

In any case according to the anti-realist of your account any conjecture which cannot be known to be true or false is neither true nor false. That seems to be an inadequate account of truth.

Also you haven't addressed the 'God' and 'multiverse' examples. Leaving aside God (since the idea could be argued to be incoherent) what about the multiverse? We could never even in principle prove there is or is not a multiverse. Would the anti-realist claim there is no fact of the matter?

Frankly, there was a lot in the post I made above that remains unaddressed, yet far more pertinent to the issue than the direction you are taking.

https://thephilosophyforum.com/discussion/comment/947737

it remains unclear how this helps the topic, or relates to it any more than bringing in intension. — Banno

So we have this:

Sentences (1) and (2) mean the same thing.

Dummett then argues that (2) is only meaningful if it is verifiable. This is his Language Acquisition Argument.

If (1) and (2) mean the same thing and if (2) is only meaningful if it is verifiable then (1) is only meaningful if it is verifiable.

If (1) is only meaningful if it is verifiable then unknowable truths make no sense.

Sentences (1) and (2) mean the same thing. — Michael

Well, no. That's far too vague. One is about the weather, the other is about a sentence. But (1) and (2) are arguably truth- functionally equivalent.

Dummett then argues that (2) is only meaningful if it is verifiable. This is his Language Acquisition Argument. — Michael

Ok, so are you agreeing with Dummett? I gave examples above of truths that are apparently not verifiable, and my conclusion is that verification is insufficient for a complete theory of truth. I waved at Tarski and deflation as alternatives. Next?

If (1) is only meaningful if it is verifiable then unknowable truths make no sense. — Michael

And if verification is a poor theory of meaning and of truth, this is of no consequence.

We are sometimes surprised by things that are unexpected. How is this possible if all that is true is already known to be true? — Banno

The claim isn’t that all truths are known. The claim is that all truths are knowable. Remember, anti-realists reject Fitch’s conclusion.

Overwhelmingly, you and I agree as to what is true. How is that explainable if all there is to being true is attitudes? How to explain why we share the same attitude? — Banno

The claim isn’t that all truths are attitudes. The claim is that all truths are knowable.

We sometimes are wrong about how things are. How can this be possible if all that there is to a statement's being true is our attitude towards it? — Banno

The claim isn’t that all truths are attitudes. The claim is that all truths are knowable.

I honestly don’t understand what you think antirealism is.

Remember, you claim to be a mathematical antirealist. Presumably you accept that mathematical truths aren’t attitudes and that there are unknown mathematical truths. So simply extend your understanding of propositions about numbers to propositions about medium sized dry goods.

The claim isn’t that all truths are known. The claim is that all truths are knowable. Remember, anti-realists reject Fitch’s conclusion. — Michael

Yeah, they can reject it all they like. It doesn't follow that they are right. ∀p(p→◊Kp)⊢∀p(p→Kp

The claim isn’t that all truths are attitudes. The claim is that all truths are knowable. — Michael

...and knowledge is a propositional attitude, a relation between someone and a proposition. Same fish. SO if all truths are knowable, all truths are attitudes. Do you hold that truths are attitudes?

Remember, you claim to be a mathematical antirealist. Presumably you accept that mathematical truths aren’t attitudes and that there are unknown mathematical truths. So simply extend your understanding of propositions about numbers to propositions about medium sized dry goods. — Michael

I hope I made it very clear that realism and antirealism are different ways of talking, and that

...one can be a realist in one area and an anti-realist in another. — Banno

If you think this is wrong, tell me why.

Well, no. That's far too vague. One is about the weather, the other is about a sentence. But (1) and (2) are arguably truth- functionally equivalent. — Banno

I’m confused. Are you a truth deflationist or not? A truth deflationist will accept that (1) and (2) mean the same thing. But now you say that they don’t mean the same thing and are only “truth-functionally” equivalent. That strikes me as being decidedly non-deflationary.

Ok, so are you agreeing with Dummett? — Banno

I’m just offering an example of what I think is a deflationary anti-realism.

Yeah, they can reject it all they like. It doesn't follow that they are right. ∀p(p→◊Kp)⊢∀p(p→Kp — Banno

As the SEP article says, “Fitch’s proof is not a refutation of anti-realism, but rather a reason for the anti-realist to accept intuitionistic logic. … without double negation elimination one cannot derive Fitch’s conclusion ‘all truths are known’”.

If you think this is wrong, tell me why. — Banno

I don’t think it’s wrong. I just don’t understand why you think that antirealism about mathematics doesn’t entail that all mathematical truths are known/attitudes but that antirealism about the weather entails that all truths about the weather are known/attitudes.

I’m confused. Are you a truth deflationist or not? A truth deflationist will accept that (1) and (2) mean the same thing. But now you say that they don’t mean the same thing and are only “truth-functionally” equivalent. That strikes me as being decidedly non-deflationary. — Michael

One way to give a deflationary account of truth is to say that "P" is true IFF P. Hence for any statements of the sort ("P" is true) we can write P, removing "...is true". Nothing here about meaning. Deflation of truth doesn't equate to deflation of meaning.

As the SEP article says, “Fitch’s proof is not a refutation of anti-realism, but rather a reason for the anti-realist to accept intuitionistic logic. — Michael

Yep. And as I have said, the difference is a choice between ways of talking about stuff. I'm not arguing that antirealism is always wrong.

I just don’t understand why you think that antirealism about mathematics doesn’t entail that all mathematical truths are known/attitudes but that antirealism about the weather entails that all truths about the weather are known/attitudes. — Michael

The choice is between saying that there are unknown mathematical truths and saying that there are unknown physical truths. I'd entertain Kripke's approach to truth for maths but not for physics. So we can usefully say that Goldbach's conjecture so far has no truth value but that there is water on Miranda is either true or it is false.

Is that so hard?

How long is each warble in Farnarkling?

A warble lasts exactly as long as John Clark says it lasts. "A warble lasts 23 minutes" is neither true nor false, until Clark decides...

But now, not.

Another case where antirealism might be of more use than realism.

The choice is between saying that there are unknown mathematical truths and saying that there are unknown physical truths. I'd entertain Kripke's approach to truth for maths but not for physics. So we can usefully say that Goldbach's conjecture so far has no truth value but that there is water on Miranda is either true or it is false. — Banno

How do you get from “there are unknown mathematical truths” to “Goldbach's conjecture so far has no truth value”? And who has denied that that there is water on Miranda is either true of false?

Again, you don’t seem to fully acknowledge the distinction between being knowable and being known.

If Goldbach’s conjecture is provable then even if it hasn’t yet been proven it is true.

If water on Miranda is provable then even if it hasn’t yet been proven there is water on Miranda.

Perhaps the best way to understand antirealism is to rephrase Putnam’s argument against metaphysical realism: if there are unknowable truths then it is possible that “we are brains in a vat” is an unknowable truth. It is not possible that we are brains in a vat. Therefore, there are no unknowable truths.

The problem with realism is that it entails this kind of global skepticism. If there are unknowable truths then there are unjustifiable truths, and if there are unjustifiable truths then a proposition not being justified is not a good reason to reject it.

In fact, for all the realist knows, perhaps almost all truths are unknowable and so unjustifiable, which arguably gives them even less reason to reject an unjustified proposition.

"P" is true IFF P. — Banno

The above sentence is true because the sentence fragment on the left hand side (“‘P’ is true”) means the same thing as the sentence fragment on the right hand side (“P”).

You appear to be trying to conflate deflationism and disquotationalism. They are not the same thing. One can be a non-deflationary disquotationalist (in fact I seem to recall Tarski as thinking of his theory as a type of correspondence theory).

I think a better example is: “Banno has stopped beating his wife”.

Assuming, I hope, that you have never beaten your wife.

If Goldbach’s conjecture is provable then even if it hasn’t yet been proven it is true. — Michael

That's... rather the point at issue...

...“we are brains in a vat”... — Michael

:roll: Let's not.

The above sentence is true because the sentence fragment on the left hand side (“‘P’ is true”) means the same thing as the sentence fragment on the right hand side (“P”). — Michael

Nuh. It can just be extensionally equivalent. Tarski and Davidson and so on. Meaning needn't feature.

You appear to be trying to conflate deflationism and disquotationalism. — Michael

I used disquotation as an example for deflationary method. That's not hard.

I think a better example is... — Michael

You don't get the humour, then. Not a surprise.

(Edit: nor the point, actually, which was about constructivism, in this case in satire rather than in mathematics - something your "better" example misses)

It seems to me that you ignore most of what I've writ, preferring to nit pick a few near-irrelevancies.

Yawn.

It seems to me that you ignore most of what I've writ, preferring to nit pick a few near-irrelevancies. — Banno

I’m sorry but this is quite the ironic thing to say given the rest of your response to my post. Pot, meet kettle.

And I don’t think I’ve ignored anything?

:grin: Then we have a more explicit impasse.

You seem to me to be always verging on saying something interesting, which is what keeps me in the conversation... but it seldom seems to reach the point.

What is it about antirealism that you have to say?

For my part, I have I hope been at least clear that I think the difference is one of choosing between language games rather than finding the true and proper way to do ontology.

Have you understood that?

And Farnarkling. It's what we do here. My example is better.