Is it true that there are no minds in world B? — Banno

This can mean one of two things:

1. Are there no minds in World B?
2. Is "there are no minds in World B" true?

The answer to both is "yes".

And as the diagram shows, "there are no minds in World B" is a truth in World A about World B, not a truth in World B.

I'm not tying myself in knots. I'm making this very simple observation:



There are no truths in World B because nothing true is being said in World B.

But there is a truth in World A because something true (about World B) is being said in World A.

Given that nothing true is being said in a world without minds, nothing is true in a world without minds.

But something true is being said in the actual world in which there are minds at/about a world without minds.

As it stands, I have no clear idea of what the point you were attempting to make was. My apologies for attempting to take you seriously.

I will try not to do it again. — Banno

This line of discussion started from this comment of mine:

What some are saying is that "a truth" means "a true proposition" and "a falsehood" means "a false proposition", that a proposition requires a language, and that a language requires a mind.

This is not to say that a mind is sufficient; only that it is necessary. The (often mind-independent) thing that the proposition describes is also necessary (to determine whether or not the proposition is a truth or a falsehood).

So the claim is that when all life dies out there will be gold in Boorara but no truths or falsehoods because there will be no propositions. — Michael

In even simpler terms, there is gold in Boorara even if nothing is being said but there are no truths if nothing true is being said and no falsehoods if nothing false is being said.

You finally now seem to agree with me.

or was trivial, all along. — Banno

Yes, as it was always meant to be. It was a simple remark about how people were being imprecise with their use of the terms "true" and "truth". I thought this post from 11 days ago was clear enough, and yet still people were misunderstanding me and accusing me of saying something I'm not, despite me repeatedly and explicitly saying that I am being misunderstood and am not saying what I am being accused of saying.

Hence what we say is not all there is to truth and falsity. There is, in addition, what is the case. — Banno

I didn't say that saying things is all there is to truth and falsity. I said that saying true and false things is all there is to truth and falsity.

The diagram above is very clear. The existence of gold determines whether what we say is true or false, but it is nonetheless what we say that is true or false, not some other thing such that there are truths even if nothing true is said and falsehoods even if nothing false is said.

This invokes the existence of a new entity, the proposition, in the word in question. — Banno

It doesn't. We simply say true or false things or we don't, and that's all there is to truth and falsity. Your suggestion that there are truths in World B even though nothing true is being said in World B makes no sense – unless you're arguing for platonism, which I also think makes no sense.

But there are true things being said in World A about World B.

Which isn't to say that it's false, it's to say that it's not there. — fdrake

Yes, precisely. I'm only saying that truth is a property of propositions and that there are no true propositions (truths) in a world without language (i.e inside the World B circle). There are also no false propositions (falsehoods) in a world without language.

Maybe this diagram is easier to understand. The quoted sentences represent true (blue) and false (red) propositions.



Something is true in a world if it appears as a blue sentence in that world's circle. Something is true at a world if its truth conditions appear inside that world's circle.

In the above case there are no truths in World B even though there are two truths at World B.

The platonist places true and false propositions inside the World B circle even though there's nobody in World B to say those things, and I don't think that makes any sense.

There's gold in A. There's gold in A-H. Gold is an entity in both of their domains.
"There is gold" is true at A, "There is gold" is true at A-H.
"There is gold" is true in A. "There is gold" is false in A-H.

Make sense so far? — fdrake

No, it should be:

"There is gold" is true at A, "There is gold" is true at A-H.
"There is gold" is true in A. "There is gold" doesn't exist in A-H.

In addition, imagine who could possibly make the speech act that "There is gold" is true at A-H. — fdrake

You're doing it right now.

there's no one with language in A-H. — fdrake

That's why there isn't a true sentence in A-H.

Moreover, your opponents are arguing that to be true is to be true in a world - I think that's what you see it as anyway. And you say that this entails a platonism, like it's a bad thing? — fdrake

Well, it's a bad thing if platonism is wrong, which I think it is, and as Banno has claimed to be a mathematical antirealist I take him to be an anti-platonist, and so if he were to claim that to be true is to be true in a world then he would have to abandon his realism in favour of a strong anti-realism, so there appears to be some sort of inconsistency there.

Now it's not incoherent, it's simply platonist. — fdrake

Well, it may be that platonism is incoherent, which some argue it is.

But truth at a world has the same trans-world property that made truth in a world incoherent, for you, with regard to truths. — fdrake

I don't understand this. Take a variation of what I said above:

1. Something true can be said about a world without language
2. Something true can be said in a world without language

(2) is certainly incoherent but (1) doesn't appear to be.

As an example: "the Earth would still exist even humanity were to go extinct". This is an English language sentence about a world in which no English sentence is spoken or written. It seems meaningful and is arguably true (especially if one is a realist).

Although, as I mentioned a few pages ago, whether or not (non a priori) counterfactuals are truth-apt is questionable.

Maybe the issue is that you and I have very different interpretations of the difference between truth in a world and truth at a world.

All I mean is to make this distinction:

1. Something true can be said about W (truth at a world)
2. Something true can be said in W (truth in a world)

Which gives us:

3. Something true can be said about a world without language
4. Nothing true can be said in a world without language

(4) is a truism.

And unless platonism is correct, saying something true or false is all there is to truth and falsity – there are no mind-independent abstract truth-bearers.

Your T_@ behaves the same as their T_R, so your T_@ entails their T_R — fdrake

Okay, but what does that have to do with T_I? My claim is that nothing is T_I relative to a world without language but that some things are T_@ relative to a world without language. If all you are claiming is that T_R and T_@ mean the same thing, and so some things are T_R relative to a world without language then this does not contradict anything I'm saying.

You'll probably claim that it's your opponents who are equivocating T_I with T_R, your opponents will claim you're equivocating T_R with T_I, and IMO everyone's right, but no one's actually arguing about what they disagree about. — fdrake

That's not what's happening.

All that's happening is that I'm explaining that there is a difference between T_I ("truth in") and T_@ ("truth at"), and that nothing is T_I relative to a world without language (unless platonism is correct).

And then some seem to think that I’m saying that the existence of gold depends on the existence of language, despite me repeatedly denying this.

Then you're not addressing what I'm saying, because those are all I'm saying.

Then perhaps you can tell me which, if either, of these you disagree with?

1. "a truth" means "a true sentence"
2. Sentences are not mind-independent abstract objects à la platonism

I am simply saying that you are simply refusing to play ball. — fdrake

With what? The problem as I see it as that you and others think I'm saying something I'm not and now you're criticising me for not defending what I'm not saying.

What insane interpretation? I am simply making two simple claims:

1. "a truth" means "a true sentence"
2. Sentences are not mind-independent abstract objects à la platonism

Do you disagree with either of these?

This is the kind of thing I am arguing against:

It misleads Michael to think that truths only exist when sentences exist. — Banno

I am saying that a truth is a true sentence, much like a falsehood is a false sentence, and that, contrary to platonism, a sentence (whether true, false, or neither) only exists if a language exists, because sentences are not mind-independent abstract objects.

That is all.

Entities aren't true or false though? Unless they're sentences. "there is a rock" is true or false. The rock isn't true or false. This might be a pedantic point but I don't know. — fdrake

Yes, that's the point I have been trying to make for over a week.

It's presumably because the things you're saying appear to entail lots of absurd and counterintuitive things. — fdrake

If you're referring to C2 and C3 here, I do explain how we avoid them. I don't think the issue is with anything I have been saying but with the T-schema being imprecise (or misinterpreted).

Much like the idea that propositions are somehow trans-world and nevertheless language items. — fdrake

I don't think there's anything absurd or counterintuitive about us using the English language to describe possible (non-actual) or counterfactuals worlds.

I have honestly no idea what the point of this discussion is. — fdrake

I am simply saying that truth is a property of truth-bearers and that truth-bearers are features of language (i.e. platonism is wrong), and so therefore nothing that exists in a world without language has the property of being either true or false.

I don't think that this is anything controversial (unless you agree with platonism) or substantial, and so I don't understand the resistance I'm facing. I can only assume that people think I'm saying something I'm not.

The world isn't empty without language in it though. There'll still be rocks and gold. — fdrake

I know.

Which will mean statements like "this is gold" evaluates to true in that world, not just at it. — fdrake

If the proposition "there is gold" is true in that world then platonism is correct, and I do not believe that platonism is correct. If platonism is incorrect then "there is gold" is only true at that world.

But in a vacuous sense, since there are no descriptions to be true or false. — fdrake

And that's all I've ever been saying. If nothing is being said then nothing true is being said. The notion that there are truths and falsehoods without something true or false being said makes no sense to me.

If you think that truths are required for something to exist (and that falsehoods are required for something to not exist?) then that's on you. I certainly don't think it follows.

I'm repeating it because you don't seem to be addressing it. You seem to think I'm saying something I'm not and addressing that instead.

From Truth in a World vs. Truth at a World

One way for something to be true with respect to a world requires the truth-bearer to exist in the world and be true there. Another way is for the truth-bearer to “correctly describe” the world, where this does not require existing in the world.

...

The conceptualist may claim that propositions can be true at worlds without being true in them, by analogy with the examples from Pollock and Buridan. A proposition like <there are no propositions> is true at certain possible worlds but true in none.

All I am saying is that there are no truths (true propositions) in a world without language. Either this is true or platonism is true, and I don't believe that platonism is true.

See here for a visual representation.

With that established we can then consider something like the T-schema:

"it is raining" is true iff it is raining

This can be interpreted in one of two ways:

a. "it is raining" is true in world A iff it is raining in world A
b. "it is raining" is true at world A iff it is raining in world A

If we interpret the T-Schema according to (a) then we are left with the other argument I gave:

P1. "it is raining" is true in world A iff it is raining in world A
C1. Therefore, it is raining in world A iff "it is raining" is true in world A
P2. If "it is raining" is true in world A then "it is raining" exists in world A
C2. Therefore, if it is raining in world A then "it is raining" exists in world A
C3. Therefore, if "it is raining" does not exist in world A then it is not raining in world A

You took issue with P2, but if you understand what it means for something to be true at a world but not in that world then you should understand what it means for a proposition to exist or not in a world.

That leaves us with either accepting C2 and C3 or rejecting P1.

If we reject P1 then we can re-interpret the T-schema according to (b) and/or we can amend P1 to:

P1. If "it is raining" exists in world A then "it is raining" is true in world A iff it is raining in world A

Either option allows us to avoid C1 and C2.

Per your view there aren't many truths in the present either. — frank

Yes, we’re not saying many true things in the present.

But there are many mountains and planets and so on.

The set of present Kings of France is empty. — Banno

And the set of truth bearers in a world without language is empty. Therefore if truth is a property of truth bearers then the set of truths in a world without language is empty (even if the set of gold in a world without language is not empty).

One of these is false:

1. Particles cannot influence one another faster than the speed of light (locality)
2. Particles have well defined properties before being measured (realism)

As examples, the Copenhagen and Many Worlds interpretations reject realism, and the de Broglie–Bohm theory rejects locality.

That's an ambiguous question.

Given that no King of France exists, a case can be made that "the King of France is bald" is neither true nor false, and is why I specifically phrased my conclusion as "not true" rather than "false".

With that in mind, the case can be made that "the King of France is bald" is false if and only if the King of France exists and is not bald, and so yes, it would follow.

What about 'If "the king of France is bald" is false then " the King of France exists" is true? — Janus

What about it?

There is at that world no sentence "there is gold in those hills" that is either true or false; and yet there is still gold in those hills. Hence it is truth that there is gold in those hills, and that the sentence "there is gold in those hills" is true. — Banno

You appear to be switching between truths in a world and truths at a world, given that you start by saying that there is no sentence that is either true or false and then end by saying that there is a sentence that is true.

The nature of this oddity is that the sentence (proposition may be a better choice here) is not one of the things in the world, but a construct from those things. This is shown by the substitutional interpretation, but hidden by interpretations that treat sentences as what we might loosely call something like "substantial" things such as hills and gold...

In a second-order logic sentences such as f(a) and ∃(x)f(x) are not in the domain. — Banno

I still don't see the problem with the premise. Do you find anything objectionable about the below?

1. If the King of France is bald then the King of France exists

Perhaps performing a T-schema substitution will make it clearer:

1. If "the King of France is bald" is true then "the King of France exists" is true

And then, using modus tollens:

2. If "the King of France exists" is not true then "the King of France is bald" is not true.

Michael was poking around in this when he earlier said that realism inevitably courts skepticism. — Leontiskos

I didn't say it. I just quoted the IEP article on brains in a vat:

One proposal is to construe metaphysical realism as the position that there are no a priori epistemically derived constraints on reality (Gaifman, 1993). By stating the thesis negatively, the realist sidesteps the thorny problems concerning correspondence or a “ready made” world, and shifts the burden of proof on the challenger to refute the thesis. One virtue of this construal is that it defines metaphysical realism at a sufficient level of generality to apply to all philosophers who currently espouse metaphysical realism. For Putnam’s metaphysical realist will also agree that truth and reality cannot be subject to “epistemically derived constraints.” This general characterization of metaphysical realism is enough to provide a target for the Brains in a Vat argument. For there is a good argument to the effect that if metaphysical realism is true, then global skepticism is also true, that is, it is possible that all of our referential beliefs about the world are false. As Thomas Nagel puts it, “realism makes skepticism intelligible,” (1986, 73) because once we open the gap between truth and epistemology, we must countenance the possibility that all of our beliefs, no matter how well justified, nevertheless fail to accurately depict the world as it really is. [See Fallibilism.] Donald Davidson also emphasizes this aspect of metaphysical realism: “metaphysical realism is skepticism in one of its traditional garbs. It asks: why couldn’t all my beliefs hang together and yet be comprehensively false about the actual world?” (1986, 309)

The Brain in a Vat scenario is just an illustration of this kind of global skepticism: it depicts a situation where all our beliefs about the world would presumably be false, even though they are well justified. Thus if one can prove that we cannot be brains in a vat, by modus tollens one can prove that metaphysical realism is false. Or, to put it in more schematic form:

If metaphysical realism is true, then global skepticism is possible
If global skepticism is possible, then we can be brains in a vat
But we cannot be brains in a vat
Thus, metaphysical realism is false (1,2,3)

The problem is that his idiosyncratically defined "anti-realism" doesn't seem to offer a substantive alternative. — Leontiskos

It's not my "idiosyncratically defined" anti-realism. It just is what anti-realism is according to Michael Dummett, the man who coined the term "anti-realism":

For Dummett, realism is best understood as semantic realism, i.e. the view that every declarative sentence in one's language is bivalent (determinately true or false) and evidence-transcendent (independent of our means of coming to know which), while anti-realism rejects this view in favour of a concept of knowable (or assertible) truth. Historically, these debates had been understood as disagreements about whether a certain type of entity objectively exists or not. Thus we may speak of realism or anti-realism with respect to other minds, the past, the future, universals, mathematical entities (such as natural numbers), moral categories, the material world, or even thought. The novelty of Dummett's approach consisted in seeing these disputes as at base analogous to the dispute between intuitionism and Platonism in the philosophy of mathematics.

@Banno, @Janus, @Srap Tasmaner

A painting of a mountain is accurate or inaccurate (allowing for degree). A description of a mountain is true or false (allowing for degree).

If there are no paintings then there is no X such that X is accurate/inaccurate (it makes no sense to say that the mountain is accurate/inaccurate). If there are no descriptions then there is no X such that X is true/false (it makes no sense to say that the mountain is true/false). But the mountain still exists even if it isn't painted or described.

This is all I am saying.

You talked before about truth being a relation between a sentence and something else in the world. Well, there is only a relation between a sentence and something else in the world if there is a sentence.

All I am explaining is that truths-without-sentences doesn’t make sense (much like truths-without-other-things-in-the-world doesn’t make sense).

I really think that this post (also from six days ago) is pretty clear.

The traditional view is that there are truth-makers and truth-bearers. Truth and falsehood are properties of truth-bearers, not properties of truth-makers, and not the truth-makers themselves.

If the appropriate truth-maker exists/occurs then the truth-bearer is true, otherwise the truth-bearer is false.

A truth-maker can exist even if a truth-bearer doesn't, but if a truth-bearer doesn't exist then nothing exists that has the property of being either true (correct/accurate) or false (incorrect/inaccurate). — Michael

I don't really know what the practical implications of your view are. — frank

There aren't any. This was never meant as some deep, substantive philosophical point. I was simply explaining the ordinary grammar of the word "true". Which is why I don't understand why I have faced such fervent opposition.

It's almost as if you and other think I'm saying something I'm not.

The existence of a planet is a state of affairs. So you accept that there are states of affairs that have not been described. — frank

Here's a post of mine from six days ago:

And the existence of gold does not depend on us saying "gold exists". — Michael

There is some state of affairs even when there is no one to describe it, right? — frank

What do you mean by a state of affairs?

If you're asking if planets exist that haven't been described, then yes. I have explicitly said this many times.

But planets aren't truths and nor is truth a property of planets. Truth (and falsity) is a property of the sentences that describe a planet (or try to).

Do you have to have those descriptions in hand in order for there to be truth? Where no description is available (say about something across the galaxy), would you say there is no truth? — frank

You are asking this question:

Do you have to have those descriptions in hand in order for there to be true descriptions? Where no description is available (say about something across the galaxy), would you say there is no true description?

I don't even understand how to answer such a question. It seems inherently confused.

I understand what you're saying. You're saying truth is a concept that couldn't have been meaningful 50 million years ago because there was no one to recognize any kind of concept. From our point of view, there were rocks and clouds, but those concepts didn't exist then, which means there was no one to observe that they existed. — frank

I'm saying that a truth is something like a correct description, that a falsehood is something like "an incorrect description", that descriptions didn't exist 50 million years ago, and so that neither truths nor falsehoods existed 50 million years ago.

Even if you want to claim that descriptions are abstract and not utterances, they still depend on the existence of utterances. Perhaps we might think of them as emergent abstractions.

It misleads Michael to think that truths only exist when sentences exist. — Banno

I don't think there's anything misleading about this:

1. Truth and falsity are properties of truth-bearers
2. Truth-bearers are features of language, not mind-independent abstract objects

The straightforward conclusion is that if a language does not exist then nothing else that exists has the property of being true or false, much like nothing else that exists has the property of being semantically meaningful.

Note that I'm not saying that if a language does not exist then nothing else exists.

As I mentioned before to frank, I think you're equivocating on the term "truth". When you talk about there being truths in (not at) a world without language you are not using the word "truth" to refer to the property that truth-bearers have, but something else.

As in, you draw a distinction between these two claims:

1. There are truths
2. There are true truth-bearers

Such that "there are truths in a world without language" is true but that "there are true truth-bearers in a world without language" is false.

But compare with drawing a distinction between these two claims:

1. There are falsehoods
2. There are false truth-bearers

Such that "there are falsehoods in a world without language" is true but that "there are false truth-bearers in a world without language" is false.

I don't think that this latter distinction makes any sense, and so I question the sense of the former distinction. If you're not saying that a truth-bearer is true then I don't know what you mean by saying that there is a truth.

They're independent of any particular mind. That's what makes them abstract objects. — frank

Do they exist if language doesn't? This is the core of the issue. If sentences are features of language then even if sentences are abstract my point still stands: if there is no language then nothing has the property of being true or false, much like if there is no language then nothing has the property of being semantically meaningful.

In the case of a proposition, it's because it's the meaning of an uttered sentence.

...

Sounds and marks are intentionally used to express truth or falsehood. — frank

I don't see how that's a better explanation. You say that meanings are truth-apt and are abstract objects that are, somehow, expressed by an utterance.

I will simply say that a meaningful utterance is truth-apt.

There's no need to resort to Platonism.