But even if no one sees the moon or talks about it, the moon is still there and so it has its identity. — litewave

Yes. What more can you tell me about the moon?

That it moves around the Earth?

That it moves around the Earth? — litewave

how do you know that?

Can you formulate the inconsistency between relativity and quantum physics? — litewave

This is a well-known topic. I'll refer you to Wikipidia, for example this. https://en.wikipedia.org/wiki/Unified_field_theory

In physics, a unified field theory (UFT) is a type of field theory that allows all that is usually thought of as fundamental forces and elementary particles to be written in terms of a single field.
There is currently no accepted unified field theory, and thus it remains an open line of research.

I mean that if you abandon the law of non-contradiction then you indeed can't have any meaningful conversation because there is no difference between what you say and the negation of what you say. — litewave

Your knowledge is simply out of date. Here is the Wiki article on paraconsistent logic. From that article:

A paraconsistent logic is a logical system that attempts to deal with contradictions in a discriminating way. Alternatively, paraconsistent logic is the subfield of logic that is concerned with studying and developing paraconsistent (or "inconsistency-tolerant") systems of logic.
Inconsistency-tolerant logics have been discussed since at least 1910 (and arguably much earlier, for example in the writings of Aristotle);however, the term paraconsistent ("beside the consistent") was not coined until 1976, by the Peruvian philosopher Francisco Miró Quesada.

In other words it is perfectly sensible to have rational discussions of the subject of how to handle logical inconsistency.

Let me give an easy to visualize example of how something like this might work. Suppose that tomorrow morning professor so-and-so in Latvia proves that there is an inconsistency in set theory, but that the inconsistency requires more than 100,000 symbols to write down [in some fixed formal language].

Therefore the following two things are true:

* Set theory as a whole is inconsistent, but

* Any theorem I can prove in less than 100,000 symbols is still valid.

Inconsistency is no barrier at all to rational discourse. We can and do reason rationally about inconsistent logical systems.

how do you know that? — Hachem

Because we observe it. And the physical laws that enable us to make successful predictions and technology also say that the moon moved around the earth long before we observed it.

agreed.

In physics, a unified field theory (UFT) is a type of field theory that allows all that is usually thought of as fundamental forces and elementary particles to be written in terms of a single field.
There is currently no accepted unified field theory, and thus it remains an open line of research. — fishfry

I still don't see the inconsistency. If the combination of relativity and quantum theory says something like the electron is here and simultaneously the electron is not here then it inconsistently defines a property of the electron and thus the electron's identity. I don't see how such a theory can correspond to reality.

In other words it is perfectly sensible to have rational discussions of the subject of how to handle logical inconsistency. — fishfry

Only to the extent to which you stick to logical consistency and manage to prevent the inconsistent stuff from spreading via the principle of explosion to other parts of your system. Which is what I believe paraconsistent logic tries to do.

Only to the extent to which you stick to logical consistency and manage to prevent the inconsistent stuff from spreading via the principle of explosion to other parts of your system. Which is what I believe paraconsistent logic tries to do. — litewave

So you agree with my point that we can (under certain circumstances) speak rationally about inconsistency. Which falsifies your claim that there can be no rational discussion if some aspect of the universe is inconsistent.

As far as the rest of it, I'm not equipped to explain modern physics. Quantum theory and relativity have been known to be inconsistent with each other since the days of Einstein and the inconsistency persists to the present day. You can use Google just as well as I can so I can only suggest that you click around to find understanding.

For example here is a popularized article, but I found it exactly the same way you could: By Googling around.

Well said.

So you agree with my point that we can (under certain circumstances) speak rationally about inconsistency. Which falsifies your claim that there can be no rational discussion if some aspect of the universe is inconsistent. — fishfry

An inconsistent aspect of the universe is nonsense. We can only speak rationally if we don't insist that such an aspect of the universe exists and we rather try to find out what is wrong with our information or speak about something else. And if we abandon the law of non-contradiction completely, we cannot speak rationally about anything.

An inconsistent aspect of the universe is nonsense. — litewave

Unprovable and evidence-free metaphysical claim.

We can only speak rationally if we don't insist that such an aspect of the universe exists — litewave

Already falsified, with your agreement.

And if we abandon the law of non-contradiction completely, we cannot speak rationally about anything. — litewave

False as noted, reputable links supplied, and your agreement secured.

Unprovable and evidence-free metaphysical claim. — fishfry

Well, if a ball that is not a ball makes sense to you, I have nothing else to say.

quantum physics is inconsistent with relativity — fishfry

What? Where?

Ah! You mean it is incompatible.

Well, if a ball that is not a ball makes sense to you, I have nothing else to say. — litewave

Again you are claiming that a single inconsistent aspect of the universe [an entirely metaphysical notion] implies denial of the law of identity. I have stated that I do not follow your logic and do not agree with the claim.

Ah! You mean it is incompatible. — Banno

Yes I can see that might have been a better word. But "X is incompatible with Y" and "X is inconsistent with Y" seem to be a distinction without a difference, especially in the context quantum theory and relativity.

Again you are claiming that a single inconsistent aspect of the universe [an entirely metaphysical notion] implies denial of the law of identity. — fishfry

Identity of a thing is determined by its properties. If you say that something has and simultaneously does not have the same property you deny the identity of the thing.

Identity of a thing is determined by its properties. — litewave

Ah, identity of indiscernibles. But "properties" are imposed by sentient observers. A thing would still be a thing even if there were no people around to enumerate its properties. You're confusing physics with metaphysics again.

Well I can't argue with you about this anymore. I don't think you've made your case. And you keep making claims about "reality." As I've noted, those are statements of metaphysical beliefs. I can't argue with you about your articles of faith any more than I could argue with the Pope about matters of theology.

For me, if you say A are inconsistent, it means that they imply (materially) a contradiction. That's were I was stuck with your previous comments.

So, what you had previously said meant for me that there was some aspect of quantum mechanics that was directly contradicted by general relativity; that is, some proposition P such that, P is implied by QM, but ~P was implied by SR.

I don't think I am the only one who had read you as making this claim.

But perhaps that is cleared up now.

there was some aspect of quantum mechanics that was directly contradicted by general relativity — Banno

There is. I've given references. IMO this discussion is far past the point of diminishing returns. I have nothing to add.

I think Street's excellent point has been missed; and it is an excellent point because it is the very same one I tried to make earlier.

Dialetheism is not true; there are no propositions that are both true and false.

Arg. The references you have given do not support this claim.

So, what is it that is implied by QM, and yet its contradiction is implied by Relativity?

Set it out, man.

An inconsistent aspect of the universe is nonsense.
— litewave

Unprovable and evidence-free metaphysical claim. — fishfry

I have no problem agreeing with you on this point, but then you have also to admit the following proposition:

An inconsistent universe is a metaphysical claim.

Set it out, man. — Banno

You have the same access to Google that I do. If QM and relativity are consistent with each other then why have physicists been trying to hammer out a unified theory for over 100 years?

Please. I'm done here. I made a very simple point to start with and really have nothing more to add.

I had a tooth pulled last week. It was easier than this. Quicker, too.

It's non-locality, isn't it. Relativity implies that nothing can travel faster than light; QM says it can.

Well, I'm going to go with that.

Physicists do not conclude from this that there is an actual contradiction in the universe. Rather, they look for a way to overcome the apparent contradiction. That is, they look for descriptions of what is going on that overcome or bypass the apparent contradiction.

Contradictions occur between statements. a contradiction is an indication that one of the statements is wrong.

I showed how to dissolve the issue in the OP by providing an analysis in which the contradiction did not occur.

There is a way of dissolving the apparent contradiction between locality and non-locality. That's what physicists are looking for.

Or, alternately, it is not possible for us to construct a coherent account of reality. But that would not be a problem for reality, only for our ability to describe it; a problem of the insufficiency of language.

But what is wrong with contradictions? They are explosive.

A ^ ~A ⊃ B

Accepting a contradiction renders our accounts limitless; and hence useless.

I had a tooth pulled last week. It was easier than this. Quicker, too. — Banno

But I don't understand why I'm in this conversation. I originally said something that I thought was very innocuous. I'd sooner retract whatever it was I said than have to defend something I thought everyone already knew.

It's non-locality, isn't it. Relativity implies that nothing can travel faster than light; QM says it can. — Banno

I don't know enough physics. However I do not believe that QM lets anything go faster than light. Perhaps you have a link or some context.

Or, alternately, it is not possible for us to construct a coherent account of reality. — Banno

This is actually something I believe.

There are two different things. One is the laws of physics, which are historically contingent works of man. Aristotle, Newton, Einstein, etc. The collected body of physics papers. The stories we tell the freshmen, the stories we tell the grad students, the stories physicists tell each other.

The other thing is "reality." It may or may not have laws at all. If it does, they may or may not be knowable to us. And even the very question of whether "reality" exists as some external thing to be studied is arguably a meaningless question.

That's why when @litewave tells me what "reality" is like, I simply say that's a metaphysical belief without evidence. We can go to the university library and read the latest edition of a physics journal. We can NOT know "reality."

Contradictions occur between statements. a contradiction is an indication that one of the statements is wrong. — Banno

There are no "statements" in physics because we do not have an axiomitization of physics. That's Hilbert's sixth problem, which I linked earlier.

You are thinking there are a set of propositions in a bag called QM, and another set in a bag called Relativity, and we will find P in one bag and not-P in another.

I don't think it exactly works that way. Perhaps that's the point you're trying to make. That there is an incompatability, but not necessarily a direct contradiction. I don't think that's right. I think there are direct contradictions. But I'm perfectly willing to admit that I'm way out of my depth here.

I'm standing by for supporting evidence that QM lets things go faster than light. I know about quantum tunneling, in which a photon inside of a black hole can suddenly appear on the outside. I believe it's called Hawking radiation. Black holes give off huge amounts of energy via this magic process. I'm not sure if that's faster than light travel or not.

ps -- Ok I went Googling. But as I said earlier, we're just talking Googling here, I'm not telling anyone anything they couldn't find with the same Google search themselves. I'm not supplying physics knowledge here, just typing.

But check this out. Article titled: The Inconsistencies Between Relativity and Quantum Therory [typo in original. Maybe that's a bad sign].

http://www.quantumtemporaldynamics.com/background-physics/the-inconsistencies-between-relativity-and-quantum-therory/

Relativity tells us that if we were to capture a cube of matter exactly one Planck length to a side, the matter inside that cube will the as dense as any heart of any black hole. Quantum theory tells us that the same cube can only contain a single quanta of energy. Each statement is inconsistent with the other.

I also found:

https://www.theguardian.com/news/2015/nov/04/relativity-quantum-mechanics-universe-physicists

http://nautil.us/issue/29/scaling/will-quantum-mechanics-swallow-relativity

https://www.quora.com/Why-are-Quantum-Mechanics-and-General-Relativity-incompatible

https://io9.gizmodo.com/why-cant-einstein-and-quantum-mechanics-get-along-799561829

http://www.askamathematician.com/2009/12/q-howwhy-are-quantum-mechanics-and-relativity-incompatible/

https://physics.stackexchange.com/questions/387/a-list-of-inconveniences-between-quantum-mechanics-and-general-relativity

https://arxiv.org/pdf/1704.02587.pdf

I hope this is helpful. I haven't read any of the links except the one I quoted.

There are two different things. One is the laws of physics, which are historically contingent works of man. Aristotle, Newton, Einstein, etc. The collected body of physics papers. The stories we tell the freshmen, the stories we tell the grad students, the stories physicists tell each other. — fishfry

But why do some of these stories give correct predictions and others don't?

But if such a state of affairs obtained in reality then reality would be absurd too. But I can't imagine that reality would be absurd... — litewave

In other words, contradiction is not something that could even in principle apply - or not - to things in the world; you 'can't imagine that reality would be absurd' because absurdity is a function of your imagination, not of the world. The failure of your imagination here simply marks the indifference of the world to the things that can be said of your imagination. The mistake is in projecting that failure of thought into the world as if your failure was a positive feature of the world itself.