You mean true/false, right? — TheMadFool

No. I mean "true"

You can't play chess unless you take it as granted that the bishop moves on the one colour.

You can't shut the door unless you posit a door to be shut. Hence, realism.

But we are now off-topic.

No. I mean "true"

You can't play chess unless you take it as granted that the bishop moves on the one colour.

You can't shut the door unless you posit a door to be shut. Hence, realism.

But we are now off-topic. — Banno

So, the two metaphysical claims below are both true?

1. God exists
2. God doesn't exist

?

So, the two chess claims below are both true:
1. The bishop moves diagonally
2. The bishop moves orthogonally.

No.

Metaphysical statements are taken as true, but unjustified. — Banno

So God exists. There is no God.

We must take these statements as both true, and both requiring their own justification, rather than being a single counterfactual in which the degree to which one can be shown false, the other becomes accepted as true?

Sounds legit.

For me, to find that part where I say, "There's no way of testing this hypothesis," I invent a hypothesis that cannot be tested, and try to think why I cannot test it. Take an invisible unicorn for example. Perhaps there are invisible undectable unicorns that exist. It seems in our head like it could be true. But that's nothing we can actively test in reality, because its undetectable. — Philosophim

Let's try this hypothesis:

On a rocky planet, moon, or asteroid somewhere in this universe we call home, located one kilometer beneath the surface, is a rock formed in the exact shape and size of a 1909 svdb US copper penny.

So, there are ~10^23 stars in the universe. Let's say there's one candidate location in each star system and we can check one location every second, including travel time. Given there have been about 4 x 10^17 seconds since the universe began, that means it would take more than 2 million times as long as the universe has been around to check all the locations. Somebody check my math. Obviously, this is a very, very, very^15, conservative estimate of how long it would actually take.

To me, our hypothesis is neither true nor false. It has no truth value. It is metaphysical or meaningless. I think that's my pragmatist voice speaking.

No.

Siddhartha Gautama's cryptic response to the metaphysical question "does the Buddha live after death?" — TheMadFool

The Buddhist is concerned with a practical task, i.e. liberation from inner conflict etc. Metaphysical questions are regarded as a distraction. (Murti notes that such 'undetermined questions' have exact parallels with Kant's 'antinomies of reason' in Central Philosophy of Buddhism.)

I regard metaphysics as a worthwhile subject within a domain of discourse. The starting point of that domain of discourse are the themes in Aristotle's Metaphysics - understanding their historical precedents, how Aristotle expressed them, and how they developed in the subsequent centuries. That is a 'word game' that can be played out regardless of whether you believe any of the content or not. The thing is to try and understand the subject on its own terms. So I think the question in the OP is not on the right track, we're never going to be able to decide the truth or falsehood of classical metaphysics outside the criteria provided within that domain of discourse (especially if the Tao te Ching is taken as a metaphysical text, which it is not.)

How do you distinguish non-propositions from metaphysical claims? — TheMadFool

I'm not interested in going into that. Perhaps someone else will.

No. — Banno

So … not yes? :smile:

Well, that doesn't say much. Justification for whom? Just you, or "us" (as in your response to RussellA), or some kind of objective justification (if that's not an oxymoron)? And what kind of justification? — SophistiCat

This is not intended to be a discussion about what constitutes justification. I would enjoy participating in one if you start it. So, I'll punt - by whatever standard of justification we can agree on.

Interpretations of QM are equivalent with respect to a particular epistemic standard: that of being empirically distinguishable. — SophistiCat

Yes, that's what I meant when I wrote that all interpretations are equivalent.

But some people prefer one interpretation to another, even while acknowledging that they are empirically indistinguishable. — SophistiCat

In my judgement, interpretations that are empirically indistinguishable are the same thing. Differences between them are meaningless.

Depends on how truth is understood. Some will insist that there can be no use to asserting a proposition whose status is unknowable, so it's just a bad question.

A realist might be bound to say there is a use for this sort of thing. — frank

Yes, this is the issue I started this thread to discuss.

Too, T Clark hasn't really said anything about how metaphysical claims aren't true or false. — TheMadFool

I've said more than enough about how metaphysical claims aren't true or false. Which isn't the same as saying I've convinced you or others.

Refer back to "What is metaphysics? Yet again." That thread has taken that question about as far as I am interested in taking it right now. This is a new question, a new thread.

neither true nor false is a contradiction — TheMadFool

No, it's not.

T Clark's stand on metaphysical claims is very Buddhist. — TheMadFool

No, it's not.

The notion that metaphysical statements are neither true nor false won't bare a load. Metaphysical statements are taken as true, but unjustified. — Banno

Needless to say, I disagree.

(especially if the Tao te Ching is taken as a metaphysical text, which it is not.) — Wayfarer

Of course it is.

In practice, decidability is a pragmatic exercise. — apokrisis

I agree, although I'm not sure I mean the same thing by that statement as you do.

I would say that while we can model the world as if it has counterfactual definiteness all the way down - and so is seems that bivalent logic ought to apply - in fact Nature I only admits to being relatively divided. This makes it vague or indeterminate at base. — apokrisis

Do you mean that as a scientific statement in relation to quantum indeterminism or a metaphysical statement about truth and falsity in general.

Indeed, but

How do you distinguish non-propositions from metaphysical claims?
— TheMadFool

I'm not interested in going into that. Perhaps someone else will. — T Clark

At the least we need a way of distinguishing your mooted statements that are neither true nor false from other sentences that are mere nonsense - not even either true or false.

Otherwise the claim that metaphysics is nonsense rings hollow.

At the least we need a way of distinguishing your mooted statements that are neither true nor false from other sentences that are mere nonsense - not even either true or false. — Banno

Why don't you and @TheMadFool take that on. It isn't really relevant to the issues I'm interested in this thread.

Otherwise the claim that metaphysics is nonsense rings hollow. — Banno

I never said that metaphysics is nonsense. Your just trying to be difficult.

Your just trying to be difficult. — T Clark

Yep. Goes with the job.

Ok, I'll leave off that - seems the thread is headed off into pragmatics anyway. Let me know what you decide about the undecidable sentence in my first post.

Can a statement be true or false if it is not possible to determine which it is, even in principle?
— T Clark

Can such a statement be constructed?

"This statement is true or it is not possible to determine that this statement is true". — Banno

I don't generally find the liar's paradox very helpful in sorting things out, but I'll take a shot.

Let's start with "This statement is true," and see where that gets us. My intuition tells me 1) It can be decided whether or not the statement has a truth value and 2) The statement has no truth value. I'm not sure I can justify either assertion.

The problem is caused by the sentence's self-reference. Let's try out a couple of self-referential sentences that do have truth values:

"This sentence has five words." - That's true.
“This sentence has seven words.” That’s false.
"This sentence has an unknown number of words." - That's false. I think.

Sorry, I’m not getting anywhere. I don’t think the liar’s paradox is central to my thoughts about the decidability of the truth value of propositions, but I’d like to figure it out. I’m putting it on my list for a separate thread sometime.

Ok, I'll leave off that - seems the thread is headed off into pragmatics anyway. Let me know what you decide about the undecidable sentence in my first post. — Banno

I just posted my response, which was basically just me giving up.

(especially if the Tao te Ching is taken as a metaphysical text, which it is not.)
— Wayfarer

Of course it is. — T Clark

I’m saying that the term ‘metaphysics’ has a scope, defined originally against Aristotle, developed by the subsequent tradition. Tao Te Ching falls outside the scope. As does Vedanta and Buddhism. Which is not to say that those texts and traditions don’t deal with some of the same subjects, but they do so in very different terms, different languages and different cultural tropes. When you try and combine them all into some grand meta-subject called ‘metaphysics’ then you loose a great deal of specificity which is why you can’t find any criteria for deciding their truth or falsehood.

I’m saying that the term ‘metaphysics’ has a scope, defined originally against Aristotle, developed by the subsequent tradition. Tao Te Ching falls outside the scope. As does Vedanta and Buddhism. Which is not to say that those texts and traditions don’t deal with some of the same subjects, but they do so in very different terms, different languages and different cultural tropes. When you try and combine them all into some grand meta-subject called ‘metaphysics’ then you loose a great deal of specificity which is why you can’t find any criteria for deciding their truth or falsehood. — Wayfarer

I don't think your understanding of the meaning of "metaphysics" is consistent with how the word is generally used in philosophical discussions. It certainly isn't consistent with how I use the word.

Its not quite the liar's paradox; more like a twisted Godel sentence that shows itself to be inherently urndecdeable.

Nor is self-reference the problem, since as you show there are quite reasonable, non-paradoxical self-referential sentences, and there are also paradoxes that do not rely on self-reference.

But moreover,
"This statement is true or it is not possible to determine that this statement is true".
isn't paradoxical, if a paradox is both true and false. The issue is not that the sentence is both true and false but that the sentence is undecidable.

SO the answer to your questions:

1) Can a statement be true or false if it is not possible to determine which it is, even in principle? Then, if we can decide that question — T Clark

Seems to me we can assign "true" or "false" to the above sentence without contradiction, so the answer is "yes, there can be sentences that are true or false but undecidable".

Alternately, we might adopt a triadic logic and assign it the value "indeterminate".

2) What happens if we can't determine if the truth of a statement is decidable in principle or not?

Very little. There are, after all, other things which we not only don't know, but can't know. But we muddle on.

We can't determine if Caesar stepped into the Rubicon with his left foot. But undoubtedly he either did or din't.

Do you mean that as a scientific statement in relation to quantum indeterminism or a metaphysical statement about truth and falsity in general. — T Clark

Both. Metaphysics is in general the application of reason or rationality to the understanding of nature. Logic, or logics, are its tool. Then physics is metaphysically derived intuitions, shaped up into formal mathematical exactness, and then subjected to the informality of acts of measurement. At some point, we just agree that the evidence is “good enough”.

The central issue in the OP is he question of “which logic” ought to guide our metaphysical intuitions?

This could be good old fashioned reductionism. But history has shown that dialectical and trialectic reasoning - a move towards holism - actually deliver the better results when it comes to the forming of general intuitions. Reductionist predicate logic is what you use more in the next step of forming deductive statements that are then suitable for a process of inductive confirmation, or the experimental test of a bivalently-framed prediction.

So one thing that is clear to any logical holist is that yes/no thinking lacks sufficient sophistication. You need further categories - a third option as an answer, such as yes, no, or vague.

Pragmatism builds that answer in. The theory makes some kind of reductively bivalent claim about reality. It is a good thing to be clear in this way. But then the theory is only ever deemed verified or falsified provisionally. The evidence might lean heavily on way or the other. But always, the fact is that there remains something ambiguous or indeterminate about its truth status.

Then when it comes to quantum theory, we find ourselves bumping up against the fact that nature itself must have this same kind of logical holism. The vagueness that we need to include in our epistemic methodology becomes also a useful third category when we speak of nature “in itself”.

The alternative is to form pathological metaphysical intuitions like claiming QM proves there is a multiverse, or forever protesting that there must be “hidden variables” still to uncover.

Alternately, we might adopt a triadic logic and assign it the value "indeterminate". — Banno

:lol:

Depends on how truth is understood. Some will insist that there can be no use to asserting a proposition whose status is unknowable, so it's just a bad question.

A realist might be bound to say there is a use for this sort of thing.
— frank

Yes, this is the issue I started this thread to discuss. — T Clark

Discuss as in determine who's right? Or just to understand the diverging narratives?

Discuss as in determine who's right? Or just to understand the diverging narratives? — frank

I don't think there's a right or wrong here. I'm just trying to get my head around the issue. It's something that comes up a lot in discussions.

This doesn't seem to lead anywhere, because it involves a vicious epistemic circle. Truth or falsity are established in the framework of some epistemic standards. Janus's statement questions one epistemic standard, which is fine, but the resolution will require some other epistemic standards, distinct from the one that is being questioned. — SophistiCat

The question in my mind was not about establishing truth or falsity, but as to whether we should think that there could be truths that can never, even in principle, be established. Of course, it is true that anything we could never establish could be of no import to us. But the question is not about whether something is of import to us, but whether truth is completely independent of our interests or our ability to establish it.

You're right about one thing, though; the question doesn't really lead anywhere, especially if you think, as I do that it is undecidable. The best it could offer would be by way of the most general orientation to things.

Metaphysics is in general the application of reason or rationality to the understanding of nature. — apokrisis

Wouldn’t that be more the domain of natural philosophy i.e. science? Like, for example, physics is observing experimental results. Metaphysics is considering what they mean (as in the interminable debates about quantum physics.)

Similar to the idea of 'naturalised epistemology' in analytical philosophy.

Considering "there is a god beyond our comprehension" as an example of a proposition which we can never know even in principle whether true or false.
So, the answer to T Clark's question is yes, a proposition such as "there is a god beyond our comprehension" not only can be true or false but must be either true or false.

In answer to @SophistiCat's question as to where does this lead, it leads to the knowledge that there are some things that are beyond our comprehension. — RussellA

@T Clark had said that the question of God's existence is truth apt (unlike absolute presuppositions; a point I'm still not clear about). Someone else raised the mutliverse conjecture, and someone said we may answer be able to answer this. I don't think this is correct; the truth of even testable scientific theories can never be determined; all we know is they work...until they don't...or another theory works better.

So, now we have two examples of possibilities we can imagine the truth of which can never be determined, even in principle. It seems natural to think that despite our inability to determine the truth status of such imagined possibilities, that there must be some truth of the matter regarding them.

I think that the truth-status of such conjectures is undecidable; that is I can't decide whether we should say they could be true or false, or that they cannot be true or false.