The answer is that it is up to us to choose. — Banno

That’s why it’s antirealism. We decide if the Perseus is the Theseus. Unlike, for the sake of argument, whether or not Donald Trump is Joe Biden.

Is that picture a duck or a rabbit? It's a picture that can be seen either way. Neither is obligatory.

Further, and more importantly in this case, it is a real picture.

I know it’s real. Antirealism doesn’t say that things aren’t real. You seem to have a fundamental misunderstanding of antirealism if you think that this has any bearing on the discussion.

Anti-realism isn't concerned with explosion as a logical matter, it (the middle-way anti-realism) is concerned with how all truths are known yet some truths are unknown (anti-realism plus non-omniscience) in a meaningful (non-incoherent/useful) way. — Ennui Elucidator

Bloody hell - look at tall the parentheses.

That's doing my head in, since it looks as if you are both disagreeing with and yet asserting the same thing.

So on the one hand you say anti-realism is not concerned with explosions.

And immediately you follow this by asserting the contradiction that all truths are known yet some are unknown.

I think that just blew up.

Priest waves at relations, but again it's not clear to me that this helps his case. Sure, knowledge and belief are relational, and we tend to ignore this part. But introducing it seems prima facie to run in the face of omniscience. If knowledge is to be parsed as a relation between a knower and a proposition, then we jet stuff like "Beth knows that p" and it becomes very apparent that there are things Beth does not know.

If so, it's undercutting itself because that isn't verifiable. — frank

Well, yes, but not just that. There are innumerable facts that are unverifiable. Verificationism deals with them by extending the notion of verification beyond bounds.

So you are abandoning the principle of bi-valance? — Ennui Elucidator

If you read ~ as an intuitionist, as Dummett would, then ~p only says that you haven't demonstrated p, and ~~p only says that you haven't demonstrated that you haven't demonstrated p.

Enjoy.

A vague proposition that is so vague that it doesn't have a truth value isn't a proposition. — Hanover

Yep. Seems pretty clear.

Well, yes, but not just that. There are innumerable facts that are unverifiable. Verificationism deals with them by extending the notion of verification beyond bounds. — Banno

I think Carnap walked it back from dogma to a just a proposal for shaping scientific language.

Everytime I read "verification" on this thread I replace it mentally by "falsification". Works better I think. — Olivier5

Popper had to conceded that falsificationsim requires verisimilitude. Much of a muchness, both debunked.

That’s why it’s antirealism. We decide if the Perseus is the Theseus. Unlike, for the sake of argument, whether or not Donald Trump is Joe Biden. — Michael

Then we are simply using the name "antirealism" in different fashions.

SO, what is antirealism?

I gave this:

Speaking very roughly, just to get started, realism holds that ...stuff... is independent of what we say about it; anti-realism, that it isn't. — Banno

I'll add that realism does permit us to say things about stuff. You seem to think it can't.

So give your account - what is antirealism?

If we are going to consider Carnap, then we need to bring in Quine's criticism.

IS it your plan to defend Carnap against Quine?

IS it your plan to defend Carnap against Quine? — Banno

No.

If you read ~ as an intuitionist, as Dummett would, then ~p only says that you haven't demonstrated p, and ~~p only says that you haven't demonstrated that you haven't demonstrated p. — Srap Tasmaner

I appreciate that, however I am not sure that Michael was saying that. And yes, I should have asked him if he is rejecting the law of the excluded middle rather than focusing on the principle of bivalance to be more to the point. I stand corrected.

Intuitionist Logic from SEP

Intuitionistic logic can be succinctly described as classical logic without the Aristotelian law of excluded middle:
A∨¬A(LEM)

or the classical law of double negation elimination: . . .

The point about LEM is that you give it up as an introduction rule, as a 'syntactic' matter. Semantically it means you are not entitled to assert that p is either true or false, for any p, without having shown that p is true or that p is false. (Dummett for one has no truck with third truth values. Tertium non datur.) And honestly why should we get to deduce much of anything just from p being truth-apt?

I'll leave you all to it --- my Dummett has grown rusty...

Popper had to conceded that falsificationsim requires verisimilitude. Much of a muchness, both debunked. — Banno

What an incredibly ignorant thing to say.. You should study these matters before making a fool of yourself.

The consensus seemed to be that, with all due respect to Popper, they do what they want. — frank

Of course they do, and with all due respect to ALL philosophers. Nevertheless Popper did nail the issue neatly, and understood the process of research better than any other philosopher or even scientist, to my knowledge.

You should study these matters — Olivier5

I wrote a short thesis in my Honours year on this topic under the supervision of a chap who was a student of Watkins. I've read more since - that was a ways back.

See https://plato.stanford.edu/entries/popper/#ProbKnowVeri

But please, explain my error.

Cheers.

It's not been debunked yet. We live in a Popperian era. Or we should. Anyone discussing verificationism should check the news: the movement is dead, for the reason Frank highlighted: their criteria only worked for empirical facts themselves, not for theories or law.

From wiki's entry on verificationism:

Popper, who had long claimed to have killed verificationism but recognized that some would confuse his falsificationism for more of it,[11] was knighted in 1965. In 1967, John Passmore, a leading historian of 20th-century philosophy, wrote, "Logical positivism is dead, or as dead as a philosophical movement ever becomes".[18] Logical positivism's fall heralded postpositivism, where Popper's view of human knowledge as hypothetical, continually growing, and open to change ascended,[11] and verificationism became mostly maligned.[2]

My token identity is maintained, despite the flux of my physical body, by the way I think and talk about myself (and the way others think and talk about me). I'm the same person that was alive 20 years ago because that's how I think and talk about myself. That's anti-realism. — Michael

The realist explanation is that you are a unique changing organism with a history that extends from your birth to your death. You also have a unique genetic signature (DNA).

A vague proposition that is so vague that it doesn't have a truth value isn't a proposition. A propositional statement is defined as a statement with a truth value that is either true or false.

If no statements, as you've argued, have single truth values, then no statements are propositional. — Hanover

Well then, you must conclude that no statements are propositional.... (says he, propositionally), because all statements in human language are ambiguous, to a small or large degree.

In my example, the challenge is "try it and see", which still strikes me as an epistemically healthy attitude. — Srap Tasmaner

Depends on what you do with the 'see' bit. If I were unsure of the location of an oasis, would we verify it by looking down the road and 'seeing'? No, because we're used to mirages, they're part of our belief system already, so when we 'see' what looks like an oasis we automatically distrust that particular feedback from reality.

So when Hanover fails to lift the car, why trust that particular feedback from reality? It's not currently part of you system of beliefs that such feedbacks are unreliable - we know about mirages, we don't know about 'saw-a-man-fail-to-lift-a-car-but-really-he-did's.

The point I'm generally making here (and this goes for @Hanover as well) is that no-one assumes all of their models are exact representations of an external reality, and no-one assumes none of them are. The choice over which we behave as if were true and which we approach with uncertainty is a psychological issue, not a philosophical one.

For the same reason I mentioned playing a game that isn't a game and looking for some winner.

I just don't see room for much discussion around this topic because the jargon involved is piled too high and it takes a long, long, long time to get anywhere with anyone ... and usually results in one or both parties involved realising they're been talking about completely different items all along.

In more simplistics terms Noumenon is a bit like Tao/Dao, in that 'speaking of it' clothes it as an entity of some sort. Noumenon is always absent from human life, and just because I say Noumenon doesn't mean I have privileged experience of it, because it literally cannot be experienced and therefore there is nothing here I am really talking about.

There is phenomenon (minus the 'there' and the 'is'). Asking about The Reality of such phenomenon is just to misunderstand the terms involved. In terms of Husserlian Phenomenology the point is not to concern ourselves with the idea of what is 'Real' but to simply explore the phenomenal experience of being a human being. To take note of what we can and cannot imagine (ie. a four cornered triangle, a sound without pitch, a box without depth or a speech without words).

In the above sense the Noumenal is instantly given thing-hood by naming it. Thing-hood is a phenomenological matter of some said item rather than some 'pointing to' an underlying nothing with no name completely outside of any possible/probably/imaginable human experience ... in that sense the Noumenon isn't anything, it is the LIMIT and we're in no position to posit that we can know something beyond our experience (direct or indirect) and such claims to do so are a pointless exercise of self-deceit.

That's the short answer off the top of my head. If it makes no sense don't worry about it :D

You're going to have to explain the relevance of this response, because I'm not seeing it. — Janus

Like Michael said:

Your very hypothetical scenario presupposes realism. Your wife is having an affair (unbeknownst to you), and then you find out. Obviously if you presuppose realism then you're going to find it absurd when you then consider anti-realism. — Michael

And Elster:

/.../ the relation between belief and observation is a two-way one, rather than the one-directional inductive process suggested by such phrases as ‘the most rational belief given the available evidence’. — baker

Yes, but that it had been going on for some time entails that it was true that it had been going on, and yet unverified — Janus

Which you can only say in hindsight, after catching your wife cheating on you. And it is only in hidsight that you will see certain past events etc. as evidence of the cheating, while at the time, you didn't.

To put crudely, a realist would need to maintain that his wife coming home late on a Wednesday is proof that she's having an affair. (For practical reasons, this is generally not feasible.)

The choice over which we behave as if were true and which we approach with uncertainty is a psychological issue, not a philosophical one. — Isaac

Is this universal, or does it differ from person to person?

Is this universal, or does it differ from person to person? — baker

I think some matters are set in stone and other vary. The very idea of an external reality I think is one such. For me, it's the difference between models within brain regions with high redundancy and models formed by the meta-structure of those regions. For example, one's model of the relationship between muscle movements and visuo-spatial awareness of limbs can be quite easily modified, but there's a structural relationship between the visual, spatial and proprioceptive areas and object vs spatial systems which I don't believe it's possible to modify.

Also, there's considerable evidence that models of things like basic physics develop in a relatively predictable order during cognitive development, so it seems likely that these are biologically driven (environmentally influenced) rather than the other way around. Whether that makes them impossible to genuinely doubt though is anyone's guess.

I mentioned the variety because I think talk of 'real' and 'not real' is just unhelpful here. We use models with differing degrees of certainty, that's all. There's no need for a binomial distinction.

Then we are simply using the name "antirealism" in different fashions.

SO, what is antirealism?

...

So give your account - what is antirealism? — Banno

It is what Dummett said it is when he coined the term.

https://iep.utm.edu/dummett/

Dummett’s most celebrated original work lies in his development of anti-realism, based on the idea that to understand a sentence is to be capable of recognizing what would count as evidence for or against it. According to anti-realism, there is no guarantee that every declarative sentence is determinately true or false. This means that the realist and the anti-realist support rival systems of logic.

https://plato.stanford.edu/entries/realism/

Idealism has long been out of favour in contemporary philosophy (though see Goldschmidt & Pearce 2017 for some recent discussion), but those who doubt the independence dimension of realism have sought more sophisticated ways of opposing it. One such philosopher, Michael Dummett, has suggested that in some cases it may be appropriate to reject the independence dimension of realism via the rejection of semantic realism about the area in question (see Dummett 1978 and 1993).

...

A semantic realist, in Dummett’s sense, is one who holds that our understanding of a sentence like (G) consists in knowledge of its truth-condition, where the notion of truth involved is potentially recognition-transcendent or bivalent. To say that the notion of truth involved is potentially recognition-transcendent is to say that (G) may be true (or false) even though there is no guarantee that we will be able, in principle, to recognise that that is so. To say that the notion of truth involved is bivalent is to accept the unrestricted applicability of the law of bivalence, that every meaningful sentence is determinately either true or false. Thus the semantic realist is prepared to assert that (G) is determinately either true or false, regardless of the fact that we have no guaranteed method of ascertaining which.

....

Dummett makes two main claims about semantic realism. First, there is what Devitt (1991a) has termed the metaphor thesis: This denies that we can even have a literal, austerely metaphysical characterisation of realism of the sort attempted above with Generic Realism.

...

According to the constitution thesis, the literal content of realism consists in the content of semantic realism. Thus, the literal content of realism about the external world is constituted by the claim that our understanding of at least some sentences concerning the external world consists in our grasp of their potentially recognition-transcendent truth-conditions. The spurious ‘debate’ in metaphysics between realism and non-realism can thus become a genuine debate within the theory of meaning: should we characterise speakers’ understanding in terms of grasp of potentially recognition-transcendent truth-conditions? As Dummett puts it:

"The dispute [between realism and its opponents] concerns the notion of truth appropriate for statements of the disputed class; and this means that it is a dispute concerning the kind of meaning which these statements have (1978: 146)."

I'll add that realism does permit us to say things about stuff. You seem to think it can't. — Banno

Not exactly. I'm saying realism cannot account for how the Perseus (the ship that returns) and the Theseus (the ship that leaves) can be the same ship, given that the mind-independent stuff (the physical material) isn't the same. The truth of "the Perseus was once known as the Theseus" is not determined by some mind-independent fact but by the way we think and talk about the ship(s) (i.e it doesn't have recognition-transcendent truth conditions) and also that there is no one correct way to think and talk about the ship(s) (i.e. the truth is not bivalent). This differs, assuming realism in one domain for the sake of argument, from a statement like "Joe Biden is Donald Trump" which does have recognition-transcendent truth conditions and is bivalent (whatever we think and say about them, Joe Biden isn't Donald Trump).

The point I'm generally making here (and this goes for Hanover as well) is that no-one assumes all of their models are exact representations of an external reality, and no-one assumes none of them are. The choice over which we behave as if were true and which we approach with uncertainty is a psychological issue, not a philosophical one. — Isaac

You say this as if your responding to something I've said.

You also have a unique genetic signature (DNA). — Janus

An exact genetic clone is in principle possible so this isn’t sufficient.

The realist explanation is that you are a unique changing organism with a history that extends from your birth to your death — Janus

That this physical process maintains token identity isn’t a mind-independent fact. It’s not unreasonable to say that given sufficient physical changes the object is no longer the same, e.g with the ship of Theseus or the grandfather’s axe it can be warranted to assert that the ship and axe at the end of the story are a different ship and axe from the start of the story. Neither conclusion is wrong.

Whether or not this history of changes maintains token identity is determined by us (the way we think and talk about the object(s)). That’s antirealism.

You say this as if your responding to something I've said. — Hanover

Oh, sorry. It was related to...

your argument is the "appeal to the stone" fallacy — Hanover

...which I should have clarified. The appeal to the stone was (so far as I understand it) supposed to refute idealism by referencing the fact that we treat things like stones as immutable facts of reality regardless of Berkeley's proposition. I'm saying the opposite. The fact that we treat stones that way has no bearing at all on the matters at issue. We all (Berkeley aside), treat some representations as immutable and others as not. The matter at issue is in the grey area where some would like to treat some given representation as immutable and others would rather not. Here the former team appeal to the stone, the latter appeal to mirages. Both are wrong because the matter at hand is clearly unlike either otherwise it wouldn't be in dispute.

One issue that tends to get overlooked with anti-realism, is that it is consistent for a person to assert anti-realism for himself, but to assert realism for other people. This is because the grammar of anti-realism is rooted in perspective, and since people don't share the same perspective, they cannot assert the same definition or understanding of anti-realism.

For example, if Alice and Bob are watching the sunset together and Alice falls asleep, Bob can verify "The sunset looks beautiful, while Alice cannot see the sun", but Alice cannot verify this. Furthermore, if Alice slipped into a coma and died of a drug-overdose, Bob could then assert "The sun still exists, but Alice does not".

In other words, Bob's anti-realism about the sun and it's relationship to himself does not extend to his understanding of the sun in relation to Alice. If Bob is to understand Alice's observations about the sun as being about his sun, then he must understand her remarks in the sense of correspondences between her perceptions of his sun and his experiences of his sun. In effect, he understands Alice as being a brain in the vat that he calls his world.

in that sense the Noumenon isn't anything, it is the LIMIT and we're in no position to posit that we can know something beyond our experience (direct or indirect) and such claims to do so are a pointless exercise of self-deceit. — I like sushi

So, are you saying there is a noumenon? Or that there isn't?

We all (Berkeley aside), treat some representations as immutable and others as not. — Isaac

Because we are wired to, yes? So it's all Kant by way of Darwin.