Cheers. There is more than one SEP article being waved about.

That applies to TKP rather than KP. I don't agree that we only know things that are not contradictory - cartesian truths. So while any particular truth might not have been known, it does not follow that every given truth is unknown. We do know things. That is, the "p" in your logic is all truths when it should be a particular truth.

But to be sure, yours has been the more interesting approach to the topic.

There is no collapse. — Wayfarer

Well, I'll leave you to convince the physicists of that,

Not saying you've done it deliberately but I think you have phrased that in a way that is misleading. The way I would put it is: "It is true that even if all life disappeared from the universe, but everything else were undisturbed, that there would still be gold in Boorara."

...

So, yes I do think we can make truth-apt statements about unperceived events. The alternative, that truth depends on knowledge, seems absurd to me. — Janus

Well, the traditional thesis is that truth depends on mind. See, for example, 's post.

I don't see that you've changed Banno's claim. Here are the two claims:

• It is true that there is gold in Boorara. If all life disappeared from the universe, but everything else is undisturbed, then it would still be true that there is gold in Boorara.
• It is true that even if all life disappeared from the universe, but everything else were undisturbed, that there would still be gold in Boorara.

Your, "It is true that," extends to the whole sentence, including the consequent. We are talking about whether it would still be true that there is gold in Boorara. Metaphysics of truth is inevitable here. Even if we talk about, "Whether there would still be gold in Boorara," we are still talking about truth.

Your argument is presumably something like this, "If three humans exist and there are no other minds, and one person dies, then it is still true that there is gold in Boorara. The second dies, and it is still true. By induction we should hold that if the third dies, it will still be true. If the truth was not affected by the death of the first two people, then surely it will not be affected by the death of the third."

But on the other hand is the argument that truths only exist where minds do. Truths are not free-floating entities, existing independently of minds. I actually don't know of any philosophers who try to set out a metaphysics of truth while ignoring this principle. There are plenty of different theories for why something would remain true if all humans died, but they all have to do with non-human or non-individual minds (including especially God). Our Western logos-centric inheritance fits very well with our current intuitions, largely because our current intuitions have been shaped by that inheritance. Aquinas can simply quote Aristotle, "The Philosopher says (Metaph. vi), 'The true and the false reside not in things, but in the intellect'" (ST).

The intuition that truth is not limited to or generated by humans is what has caused all cultures to posit deeper minds and grounds of intelligibility that are operative in creation. Secular anthropocentrism has deprived itself of these explanations, and it seems to largely be at a loss when it comes to the metaphysics of truth. It is hard for such a tradition to consider the question of whether truth presupposes mind, because the question inevitably leads away from secularism. What is at stake here is the relation between mind and the material world, and to be honest, materialists/physicalists have never really known what to make of truth. It defies materialistic categories (which is why it is associated with mind and intellect).

(In responding to Pinter we should limit ourselves to talking about perception, and not fall into the trap of talking about truth and minds. To do otherwise is heavy-handed. We need only say that what is unperceived can still exist, not that truth would exist without any minds.)

Banno will confirm whether or not this misrepresents his view, but in any case, it is my view. — Janus

Banno is stubborn, but you can still see him trying to adjust his view. For example:

This by way of separating what is true from what is known to be true. Again, that a proposition is true is a single-places predicate, "P is true"; but that we know it is true is a relation, "We know P is true". Same for what are commonly called "propositional attitudes"; a name that marks this relational aspect. — Banno

He has not reckoned with the question of how a "single-places predicate" would exist apart from minds, or why "everything else undisturbed" disturbs foxes but not truths. Banno is usually not up for these deeper questions.

I do not trust your ability to understand and present either what I am saying or what ↪Michael is saying. — Banno

It's fairly obvious that you don't understand what Michael is saying, but you're slowly coming along. I see you've now made it to my post <here>, repeating what I have already said. This is all related to your misunderstanding of the unjustified/unjustifiable distinction.

it is not time or change that changes but things. — Janus

Not really. Or, not always. I just ate dinner from the same plate I ate dinner from last week.

Anyway….not that important.

Given minor differences in translations, yes, he is, and no, they are not. Mode of perception is not perception, and neither space nor time is ever an appearance, but only that which is in space and time, is. — Mww

Again, misreading.

We have therefore wanted to say that all our intuition is nothing but the representation of appearance; that the things that we intuit are not in themselves what we intuit them to be, nor are their relations so con­stituted in themselves as they appear to us; and that if we remove our own subject or even only the subjective constitution of the senses in general, then all the constitution, all relations of objects in space and time, indeed space and time themselves would disappear, and as ap­pearances they cannot exist in themselves, but only in us. — Mww

Space and time are its pure forms, sensation in general its matter. We can cognize only the former a priori, i.e., prior to all actual perception, and they are therefore called pure intuition; the latter, however, is that in our cognition that is responsible for it being called a posteriori cognition, i.e., empirical intuition. The former ad­heres to our sensibility absolutely necessarily, whatever sort of sensations we may have; the latter can be very different for different subjects. Even if we could bring this intuition of ours to the highest degree of distinctness we would not thereby come any closer to the constitution of objects in themselves. — Mww

Please follow their argument to the fullest. It is easy to get lost with two paragraphs almost repeating themselves line by line.

Space and time are its pure forms which we can only cognize a priori. (not in themselves). This is called intuition which adheres to our sensibility absolutely necessarily. The things we intuit are not in themselves what we intuit them to be. And if we remove our own subject, then all relations in space and time, indeed space and time themselves would disappear.

There. I rearrange the lines of their argument for easy understanding.

Change requires things that change, usually in the form of movement, but nevertheless, something empirical, whereas time itself does not change. — Mww

A further distinction to made here is the difference between movement, which is a change of place known by one object's position relative to another, and internal change, which is a change within an object itself. The latter need not show itself to empirical observation.

A problem which has developed in modern physics, is the tendency to represent an object as consisting of parts, which are in themselves objects, so that internal change is represented as change of place (movement) of parts. Then all change is reduced to movement, change of place.

This is a problem because it leads to either an infinite regress of smaller and smaller parts, or else we must assume fundamental parts which are unchanging (eternal). Because of this problem, it is best to maintain the distinction between change of place and internal change, as a fundamental ontological principle.

That applies to TKP rather than KP. I don't agree that we only know things that are not contradictory - cartesian truths. So while any particular truth might not have been known, it does not follow that every given truth is unknown. We do know things. That is, the "p" in your logic is all truths when it should be a particular truth. — Banno

So we have two propositions:

1. The realist believes that it is possible for truth to be unknowable in principle.
2. The realist believes that truth is unknowable in principle.

The article asserted (1), not (2).

The problem for the realist, however, is that (under S5), (1) entails (2):

∀p(◊(p ∧ ¬◊Kp)) ⊢ ∀p(p → □¬Kp))

Hence my earlier claim that one of these is true:

1. Realism is incorrect
2. S5 is incorrect
3. Nothing is known

Some more general musings.

From here, we have these sets of propositions:

1. "the cat is in the box" is true and justified (is known)
2. "the cat is in the box" is false and justified (is not known)
3. "the cat is in the box" is true and unjustified (is not known)
4. "the cat is in the box" is false and unjustified (is not known)

5. "the cat is in the box" is true and I have looked in the box and seen the cat
6. "the cat is in the box" is false and I have looked in the box and seen the cat
7. "the cat is in the box" is true and either I have not looked in the box or I have not seen the cat
8. "the cat is in the box" is false and either I have not looked in the box or I have not seen the cat

There is perhaps a reasonable argument that if (6) is possibly true then (5) does not entail (1); that if it is possible that I look in the box and see the cat even if the cat is not in the box then looking in the box and seeing the cat does not justify the belief that the cat is in the box.

This would seem to be skepticsm.

One response is to deny the possibility of (6), and so also (2), leaving us with:

1. "the cat is in the box" is true and justified (is known)
3. "the cat is in the box" is true and unjustified (is not known)
4. "the cat is in the box" is false and unjustified (is not known)

Which can be simplified to:

a. "the cat is in the box" is justified (is known)
b. "the cat is in the box" is true and unjustified (is not known)
c. "the cat is in the box" is false and unjustified (is not known)

Jp ⊨ Kp ⊨ p

If a proposition is justified then it is true.

This would seem to be a type of antirealism.

1. The realist believes that it is possible for truth to be unknowable in principle. — Michael

I'm puzzled as to how to read this. Is it that it is possible for all truths to be unknowable or for some truths to be unknowable?

I think something like "for all p, it is possible that p is unknowable".

So take any proposition at random, e.g. that there is a suitcase under my bed. Is it possible that this is unknowable? Given that the realist argues for "mind-independent" truths, or as Gaifman describes it "that there are no a priori epistemically derived constraints on reality", it would seem that the realist must answer in the affirmative. Which, under S5, entails that it is necessarily unknown.

So particular truths. While any particular truth might have been unknown, this is different to every given truth is unknown. Is that so?

I address that here.

If "for all p, it is possible that p is unknowably true" is true then "for all p, if p is true then p is necessarily not known" is true.

You lost me.

∀p(◊(p ∧ ¬◊Kp)) says "For all truths p, it is possible that p is true and it not be possible to know p"

I think that should be "For all truths p, it is possible that p is true and yet p is not known". That would be ∀p(◊(p ∧ ¬Kp)).

The realist does not need to say that it is impossible to know that the cat is in the box, only that it is not known. It might be possible that the cat is in the box, but we just do not know.

I think you have one too many modalities.

It's an interesting argument, nice work, though.

∀p(◊(p ∧ ¬◊Kp)) says "For all truths p, it is possible that p is true and it not be possible to know p"

I think that should be "For all truths p, it is possible that p is true and yet p is not known". That would be ∀p(◊(p ∧ ¬Kp)). — Banno

There are two different claims:

1. It is possible for the truth to be unknowable
2. It is possible for the truth to be unknown

These are represented as:

1. ∀p(◊(p ∧ ¬◊Kp))
2. ∀p(◊(p ∧ ¬Kp))

Certainly (2) is true, but at least according to that SEP article realists believe that (1) is also true, and as mentioned above, (1) entails that nothing is known.

Our concern is whether or not truths are knowable not just whether or not truths are known.

1. The realist believes that it is possible for the truth to be unknowable
2. The realist believes that it is possible for the truth to be unknown — Michael

Not happy with those. Again, I think it should be
1. The realist believes that it is possible for a truth to be unknowable
2. The realist believes that it is possible for a truth to be unknown

And I'll maintain that (2) is all that realism requires.

There seems to be a lot of ambiguous phrasing in this discussion and so I want to try to be as precise as possible:

1. For some p, p is true and unknown
∃p(p ∧ ¬Kp)

2. For some p, p is true and unknowable
∃p(p ∧ ¬◇Kp)

3. It is possible that for some p, p is true and unknown
◇∃p(p ∧ ¬Kp)

4. It is possible that for some p, p is true and unknowable
◇∃p(p ∧ ¬◇Kp)

5. For all p, if p is true then p is known
∀p(p → Kp)

6. For all p, if p is true then p is knowable
∀p(p → ◇Kp)

The realist accepts (1), (2), (3), and (4) and rejects (5) and (6).

The anti-realist accepts (1), (3) and (6) and rejects (2) and (5). They probably also reject (4), although strictly speaking (4) is consistent with (6).

The problematic proposition is:

7. For all p, it is possible that p is true and unknowable:
∀p(◇(p ∧ ¬◇Kp))

This entails radical scepticism:

8. For all p, if p is true then p is not known:
∀p(p → ¬Kp)

If the realist rejects (8) then they must reject (7). Note specifically the differences between (3), (4), and (7). (7) entails (3) and (4) but neither (3) nor (4) entail (7).

But we must ask whether or not (6) really is necessary for anti-realism, and so whether or not (2) really is sufficient for realism. As the SEP article mentions, some anti-realists offer a restricted knowability principle, perhaps such as the one I offered earlier:

9. For all p and all q, if p being true does not entail that q is an unknown truth then if p is true then p is knowable
∀p∀q((p ⊭ (q ∧ ¬Kq)) → (p → ◊Kp))

This is consistent with (2), avoiding Fitch's paradox even in classical logic, but is still sufficiently anti-realist, e.g. it still asserts that if some object exists then it is possible to know that it exists. It simply acknowledges that knowing that something is an unknown truth is a contradiction.

Given this, realism must be more than just (1), (2), (3), or (4). But if it isn't (7) then what is it? Perhaps the claim that there is at least one unknowable Cartesian truth (using Tennant's terminology), e.g. that there is at least one unknowably true "the object exists"?

And note the difference between "there is at least one unknowable Cartesian truth" and "it is possible that at least one Cartesian truth is not known". These are (2) and (3) respectively (restricted to Cartesian truths). Anti-realism is consistent with (3).

First you said….

Kant is not saying here that space and time vanish as soon as the subject vanishes. — L'éléphant

Followed by…..

Because to Kant, even space and time are only appearances to us — L'éléphant

Now you say….

And if we remove our own subject, then all relations in space and time, indeed space and time themselves would disappear — L'éléphant

Hopefully this indicates you now understand the point being made in the text, that space and time belong to the subject himself, so that when there isn’t a subject there aren’t those necessary pure intuitions that belong to him, precisely what Kant meant by the disappearance of the one entails the disappearance of the other.

He never meant it to be understood they disappear in sense of being themselves appearances, which are real physical things external to the senses. When the subject disappears there is no effect on things that appear, which makes explicit space and time, iff they were appearances, wouldn’t disappear merely because the subject did, and the transcendental methodology contradicts itself. On the other hand, if space and time are not appearances but belong to the subject himself, it is a given that when the subject disappears, it is impossible space and time remain.
————-

it is best to maintain the distinction between change of place and internal change, as a fundamental ontological principle. — Metaphysician Undercover

Oh absolutely, except maybe under those conditions where such distinction is not necessary for supporting a proposition. Change is most obviously this, but it is also this and this and this.

Ya know….I wondered if I was going to be presented with the fact the plate I ate dinner on today couldn’t possibly be the same, unchanged, plate I ate on last week, insofar as electrons in the outer shells of the plate matter would have jumped to photons, or some such quantum mystique.

There seems to be a lot of ambiguous phrasing in this discussion — Michael

I quite agree. If you don't mind I will go overt the argument again, just to make sure we agree on the basics.

The SEP argument proceeds as follows:
$\forall p(p \rightarrow \Diamond Kp).$
The Knowability principle, KP: All truths are known by somebody at some time. This is taken as the antirealist premise.

And we are not omniscient:
$\exists p(p \wedge \neg Kp).$

So for some p,
$p \wedge \neg Kp.$

Substitute this into KP:
$(p \wedge \neg Kp) \rightarrow \Diamond K(p \wedge \neg Kp)$

But we already have the antecedent, so:
$\Diamond K(p \wedge \neg Kp)$

Which is false. We can't know that p is true and that p is false. So a contradiction follows from KP and non omniscience, and one of these must be false. So if all truths are knowable,
$\neg \exists p(p \wedge \neg Kp)$

and hence all truths are known:
$\forall p(p \rightarrow Kp).$

Hence Fitch's paradox, if something is true then it is known:
$\forall p(p \rightarrow \Diamond Kp) \vdash \forall p(p \rightarrow Kp)$

I'll pause there. I gather we agree at least that this is the account being scrutinised?

It is true that there is gold in Boorara. If all life disappeared from the universe, but everything else is undisturbed, then it would still be true that there is gold in Boorara.
It is true that even if all life disappeared from the universe, but everything else were undisturbed, that there would still be gold in Boorara. — Leontiskos

The mistake you are making is failing to notice the difference between "is true" and "would be true". It is true for us now that there would be gold etc., even if all percipients were wiped off the face of the Earth. That is not the same as to say it would be true that there is gold even if all percipients etc.

Actually it surprises me that being a theist you don't believe it would still be true because God would be there to know it.

it is not time or change that changes but things.
— Janus

Not really. Or, not always. I just ate dinner from the same plate I ate dinner from last week.

Anyway….not that important. — Mww

Are you sure the plate was exactly the same? Anyway my point was not that things must change, but rather that change itself does not change, just as time does not change. That said time is always changing or at least the times are. :wink:

The mistake you are making is failing to notice the difference between "is true" and "would be true". It is true for us now that there would be gold etc., even if all percipients were wiped off the face of the Earth. That is not the same as to say it would be true that there is gold even if all percipients etc. — Janus

That is a very thin attempt at an explanation. What are the two putatively different claims, how are they different, and which one am I supposed to be making?

Actually it surprises me that being a theist you don't believe it would still be true because God would be there to know it. — Janus

Banno makes that statement as an atheist who is presumably not assuming non-living minds (whether or not God counts as a non-living mind).

That is a very thin attempt at an explanation. What are the two putatively different claims, how are they different, and which one am I supposed to be making? — Leontiskos

I already explained it. We can say something is true now about what would be in the future. Can we say it would be true in the future absent us? So if truth or falsity is a property of propositions and it is true that the gold will exist in the non-human future do you say it will also be true in that non-human future that there is gold when there are no propositions?

In other words I'm suggesting that truth is propositional and existence is not.

Banno makes that statement as an atheist who is presumably not assuming non-living minds (whether or not God counts as a non-living mind). — Leontiskos

Would God be capable of knowing what is true and what is false?

Hopefully this indicates you now understand the point being made in the text, that space and time belong to the subject himself, so that when there isn’t a subject there aren’t those necessary pure intuitions that belong to him, precisely what Kant meant by the disappearance of the one entails the disappearance of the other. — Mww

I just reiterated what was in the text. How could you have missed that, too?
That's what I was saying. This is crazy when you're agreeing with me, but you don't know you're agreeing with me.

I'll pause there. I gather we agree at least that this is the account being scrutinised? — Banno

Yes. So the anti-realist responds by either rejecting the validity of the argument, given that they often support intuitionistic logic, or by accepting that the knowability principle as written is too broad, offering instead a restricted version, such as (9) in my post above, which does not allow for the substitution (p ∧ ¬Kp) → ◇K(p ∧ ¬Kp).

(9) does not entail (5) and so is consistent with (1) and (3), and also (2) and (4). If (9) is still anti-realism then anti-realism is consistent with (1), (2), (3), and (4). So realism must be saying more than just (1), (2), (3), or (4).

My suggestion is that realism is saying that there are unknowable Cartesian truths, where a Cartesian truth is a truth that it is not a contradiction to know, e.g. some instance of "the cat is in the box".

So more generally, the anti-realist is claiming that if something exists then it is possible to know that it exists, and that if it is doing something then it is possible to know that it is doing that thing. They probably even say that if something doesn't exist then it is possible to know that it doesn't exist, and that if it isn't doing something then it is possible to know that it isn't doing that thing.