I agree with your substitution. So what's the problem?

But I don't think you're quite acknowledging the nuances of realism in that post. See here where I offer an example involving cats in boxes.

For your specific example, realism entails that even if we examine the entirety of the Solar System with the most sophisticated scientific instruments possible, and even if we fail to see a cup, it might still be the case that there is a cup orbiting the Sun.

Or on the other hand, even if we do (seem to) see a cup, it might still be the case that there isn't a cup (e.g. we're being deceived by someone or something casting an illusion).

These possibilities make justification of anything rather problematic.

<A thesis which is unconfirmable/unjustifiable is not a real thesis>

Realists and anti-realists agree with this proposition. You are manufacturing a disagreement.

The realist argues that "the cat is in the box" can be true even if it's not possible for someone to look in the box and see the cat. — Michael

What realist says that? I don't know of any.

In these conversations you always conflate different senses of mind-independence. You erect a false dichotomy where, if truth is not mind-dependent then truth is wholly mind-independent, such that <A thesis which is unconfirmable/unjustifiable is a real thesis>. You are misrepresenting realism. Have you tried to define what you mean by realism somewhere in this thread?

This recent argument started as a discussion on Fitch's paradox, which examines the anti-realist's knowability principle: ∀p(p → ◊Kp).

Realists reject this knowability principle, claiming that ∃p(p ∧ ¬◊Kp).

Assuming that knowledge is justified true belief, the realist's claim is that there is at least one proposition that is true but that either cannot be believed or cannot be justified (e.g. by seeing evidence that it is the case).

Given that the realist has no a priori reason to suggest that no use of "the cat is in the box" can be one such proposition, the realist accepts that it's possible that some use of "the cat is in the box" can be true but that either it cannot be believed or cannot be justified (e.g. by looking in the box and seeing the cat).

There's also the IEP article I quoted here. Although in that specific case they consider the proposition "I am a brain in a vat" rather than the proposition "the cat is in the box".

- Seems like you're arguing against strawmen again. You impute some strange doctrine to realists, and when asked what realists hold this strange doctrine, you go silent.

Maybe you should try reading Fitch's paradox.

- Maybe you should try to find a realist who lines up with your (mis)representation.

Have you tried to define what you mean by realism somewhere in this thread? — Leontiskos

I don't understand what misrepresentation you think I've made.

Are you denying that the realist rejects the knowability principle?

Are you denying what the IEP article says below?

One proposal is to construe metaphysical realism as the position that there are no a priori epistemically derived constraints on reality.

...

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 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.

- I don't know of any realists who believe in unknowable truths. Apparently you don't either.

The problem with IEP is that it conflates "global skepticism" with the idea that "it is possible that all of our referential beliefs about the world are false." If we were to ask what "possible" means, we would receive a similar non-answer to the one you gave about "sufficiently."

I don't know of any realists who believe in unknowable truths. Apparently you don't either. — Leontiskos

Try reading the article I directed you to:

Fitch’s paradox of knowability (aka the knowability paradox or Church-Fitch Paradox) concerns any theory committed to the thesis that all truths are knowable. Historical examples of such theories arguably include Michael Dummett’s semantic antirealism (i.e., the view that any truth is verifiable), mathematical constructivism (i.e., the view that the truth of a mathematical formula depends on the mental constructions mathematicians use to prove those formulas), Hilary Putnam’s internal realism (i.e., the view that truth is what we would believe in ideal epistemic circumstances), Charles Sanders Peirce’s pragmatic theory of truth (i.e., that truth is what we would agree to at the limit of inquiry), logical positivism (i.e., the view that meaning is giving by verification conditions), Kant’s transcendental idealism (i.e., that all knowledge is knowledge of appearances), and George Berkeley’s idealism (i.e., that to be is to be perceivable).

...

The middle way, what we might call moderate antirealism, can be characterized logically somewhere in the ballpark of the knowability principle:

∀p(p → ◊Kp).

which says, formally, for all propositions p, if p then it is possible to know that p.

Notice that antirealism is defined as being the position that believes that all truths are knowable. As realism rejects antirealism (and vice versa), in follows that realism asserts that some truths are unknowable.

But if you want something more explicit, the article continues:

He also points out that TKP, rather than the unrestricted KP, serves as the more interesting point of contention between the semantic realist and anti-realist. The realist believes that it is possible for truth to be unknowable in principle.

- All I've asked is for you to give me an example of a realist who holds to your strange version of realism. You have failed to do that for many posts now.

Notice that antirealism is defined as being the position that believes that all truths are knowable. As realism rejects antirealism (and vice versa), in follows that realism asserts that some truths are unknowable. — Michael

This is evidence of your sophistry. You want antirealism to "wear the pants."

This is evidence of your sophistry. — Leontiskos

How is it sophistry? I have provided the source. It's right there, explicitly saying "the realist believes that it is possible for truth to be unknowable in principle."

All I've asked is for you to give me an example of a realist who holds to your strange version of realism. — Leontiskos

Again, read the article:

Rediscovered in Hart and McGinn (1976) and Hart (1979), the result was taken to be a refutation of verificationism, the view that all meaningful statements (and so all truths) are verifiable.

...

Mackie (1980) and Routley (1981), among others at the time, ... ultimately agree that Fitch’s result is a refutation of the claim that all truths are knowable, and that various forms of verificationism are imperiled for related reasons.

It's right there, explicitly saying "the realist believes that it is possible for truth to be unknowable in principle." — Michael

You fished out a single sentence in an SEP article? Who cares? Find a new god to put your faith in. I am asking about realists, not SEP. You need to start arguing with real people, instead of merely making arguments from authority.

You ask me for an example and then complain that it's just one example?

And you accuse me of sophistry and not being serious... :roll:

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. — Michael

Interesting that you think this a problem. That there are "unjustified" truths is pretty obvious. Of course, now we have to look towards what it is to be "justified", but I gave some examples earlier.

That Leon disagrees is affirming.

You ask me for an example and then complain that it's just one example? — Michael

I asked you for an example of a realist who holds to your misrepresentation. You didn't give one. If you did, then what is his/her name?

It's in that post above. There's Hart, McGinn, Mackie, and Routley. And of course Fitch himself.

That there are "unjustified" truths is pretty obvious. — Banno

Unjustifiable.

There's also Banno.

You are playing silly buggers until you fill in what it means for something to be justified. But given that you cannot get your head around material implication, and validity, what you have to say will not be all that useful.

:wink:

- If Banno is a realist who fits your characterization then that would be exceedingly helpful. If he had better reading comprehension his affirmation would be more promising.

- You quoted the word "unjustified" in response to a quote from Michael that does not contain that word. Instead it contains the word "unjustifiable." Trouble reading, you have.

I've responded to that quote already:

Or, "...then a proposition not being justified is not a good reason to reject it." There is an equivocation here on 'reject'. If 'reject' means falsify, then this strikes me as uncontroversial. If 'reject' means "abstain from affirming," then the consequent is false but it does not in fact follow from your premises. — Leontiskos

I'll leave you and Michael to it, and await your concession.

So you don't think unjustifiable truths are unjustified? How odd.

Or is that just pedantry in the service of your confusion?

↪Leontiskos So you don't think unjustifiable truths are unjustified? How odd.

Or is that just pedantry in the service of your confusion? — Banno

"Unjustified" and "unjustifiable" are two different things. Michael's post would be entirely innocuous if we misread "unjustified" for "unjustifiable," as you did. You are being disingenuous (again).

Every unjustifiable truth is unjustified but not every unjustified truth is unjustifiable. Realism allows for unjustifiable truths, and that is a problem.

Every unjustifiable truth is unjustified but not every unjustified truth is unjustifiable. — Michael

Yep, something doesn't seem to grasp.


And by "justification" we mean...?

The antecedent of a material implication? - too Strong, since anything can be justified that way.

So, what?

Just to be clear, my target here is the idea that a proposition can only be true if justified. That suggests truth is a two=place predicate over propositions, which it isn't.

Part of this is to point out that the notion of unjustifiable remains unclear. What is the justification for the truth of "I have a pain in my toe"? Or is it not truth-apt?

So, what? — Banno

So it entail global skepticism, which might be seen as undesirable. And if Putnam's argument is a sound refutation of global skepticism then it's a sound argument against realism.

And if the reasoning here is correct then it entails that nothing is known; my counterpart to Fitch's paradox.

Just to be clear, my target here is the idea that a proposition can only be true if justified. — Banno

But that's not what has been said. What has been said is that if a proposition is true then it is justifiable.

I don't see that you can substitute □(p → ◊Kp) for ∀p(p → ◊Kp). I've tried doing that with the argument at SEP 2. The Paradox of Knowability, but...

Substituting p∧¬Kp in to □(p → ◊Kp) gives □((p∧¬Kp) → ◊K(p∧¬Kp))

and so ◊K(p∧¬Kp) stands. Something is amiss, since Fitch's paradox still stands.

(edited).