I disagree — T Clark

I get that. And you're wrong. QM is not a matter of "different rules for small things."

Check into any quantum theory. And stop talking down to people.

Because we believe in the uniformity of nature — Srap Tasmaner

But nature clearly isn't uniform. It behaves differently depending on where you choose to look - baseballs or bosons.

the unity of science. — Srap Tasmaner

And science clearly is not unified. We have broken it down into a hierarchical list of different sciences depending on scale and principle of organization. There have been long discussions of that hierarchy here on the forum. I think the important message is that reductionism works - each higher level behaves consistently with the level below - but constructivism doesn't - you can't generally predict behavior at a higher level from principles of the lower level. Example - you can't predict the behavior of biology from chemistry.

And yes of course there are differences between how a crowd of 50,000 behaves and how a group of 5 behaves. Yes, scale matters. But it should be explicable how you crossover from one scale to the next — even if there is no simple, non-fuzzy boundary. — Srap Tasmaner

At some level I think you're right, although I'm not sure it's always possible. I think there has been a lot of work to figure out how the quantum world transitions to the classical one. That seems like a valuable thing to know, but I don't think it changes my position.

Anyhow, that's why at least one person (me) would think that wouldn't be true, based entirely on my assumptions and with hardly any knowledge of quantum theory at all. I've just never understood the "it's just a matter of scale" view — as if Mother Nature checks the size of what she's dealing with and then picks the appropriate rule-book to follow for that size object. That leaves the events at different scales isolated from each other in a way I find incomprehensible. — Srap Tasmaner

I doubt you and I would disagree with each other on a practical level. I think our metaphysical language is just different. When it comes to metaphysics, my rule is to use whatever works. Not everyone agrees with that.

I get that. And you're wrong. QM is not a matter of "different rules for small things."

Check into any quantum theory. And stop talking down to people. — frank

I disagree. Please explain how I am "talking down."

I disagree — T Clark

Can you not read something about QM and become enlightened on the topic?

Can you not read something about QM and become enlightened on the topic? — frank

Please explain how I am "talking down."

Please explain how I am "talking down." — T Clark

That's not really the topic of the thread. Here, look at me being helpful to you:

QM is not a matter of "different rules for small things." — frank

Yes, this is the view I find incomprehensible because the whole point is that our big stable things supervene upon the small unstable things. It's not like we can keep them in separate rooms with separate rules, like the rooms of a preschool.

Yes, this is the view I find incomprehensible because the whole point is that our big stable things supervene upon the small unstable things. It's not like we can keep them in separate rooms with separate rules, like the rooms of a preschool. — Srap Tasmaner

Right.

Helpful video. I now "understand" the experiment @Andrew M was trying to explain to me over in the truth thread, and it — sadly or happily — connects to the discussion I'm having with @Metaphysician Undercover about past, future, alethic modalities and determinateness. Was so hoping I could stay out of quantum stuff, but I guess I'll have to give up that dream.

I haven't watched all of this, because I try not to think about quantum mechanics, but Alastair Wilson has interesting things to say about the relation between physics and metaphysics as someone near the frontlines.

I think we're lucky we live in a time when physicists agree that physics has a philosophical dimension. I don't think that was true a few decades back.

All of the Spacetime videos are good, and he builds from easy to more advanced over the course of several videos, which helps.

Just to clarify, in terms of our folk notions of reality, QM goes far beyond saying that things work differently on a small scale. QM suggests that there is no distinct reality outside measurement events (which don't require consciousness, but human activity is a kind of measurement.)

So when you say physicists are realists, that doesn't necessarily answer the OP. If the OP had some sort of Newtonian picture of the world, then the answer is yes, QM says that a fair portion of that absolute realm is not real. — frank

There is no single ‘folk’ notion of reality any more than there is a single philosophical or scientific notion of it. There are so many variants of realism that different philosophers adhere to that it is possible to accommodate QM within one or more of them. It is true that the most traditional conceptions of the real can be ruled out by QM ( naive realism) but then we reach some difficult territory.

As far as the quotes in the OP making what is observed dependent on the existence of the observer, this shows an assimilation of Kant’s work on noumenon and phenomenon , concept and sensation, and the inaccessibility of the thing in itself. But embracing Kantianism only rules out older conceptions of the real , like Newton’s. This is why one can find a hodgepodge of realism and anti-realism within a single account of QM.

There are so many variants of realism that different philosophers adhere to that it is possible to accommodate QM within one or more of them. — Joshs

True. My point was that if we want to answer the OP successfully, we should tune into what he or she is thinking of as reality.

As far as the quotes in the OP making what is observed dependent on the existence of the observer, this shows an assimilation of Kant’s work on noumenon and phenomenon , concept and sensation, and the inaccessibility of the thing in itself. — Joshs

I don't think so. The Copenhagen interpretation (especially John von Neumann's view) is not Kant. There is no thing in itself. There is no determinate thing prior to wave function collapse, and we have a clear idea of the math that describes what's there prior to collapse.

Though on the off side...does it really say that? From what I've been told there are so many interpretations of QM that you can pretty much just have it say whatever you want. — Darkneos

Depends who you ask, Rovelli will have a different take than Sean Carroll, who differs from X and Y and so on. But quantum physics studies the extremely small. Would we then also say that QM tells us there is no pain in my fingertips? Of course not.

We err when we take these sciences and apply them in domains way beyond the intended reach.

The Copenhagen interpretation (especially John von Neumann's view) is not Kant. There is no thing in itself. There is no determinate thing prior to wave function collapse, and we have a clear idea of the math that describes what's there prior to collapse. — frank

The authors of the Copenhagen Interpretation weren’t simply duplicating Kant, but theyr were strongly influenced by him:


”Many philosophers and physicists have recognized a strong kinship between Kant and Bohr’s
thinking or a direct Kantian influence on Bohr. In the thirties C.F. von Weizsäcker and Grete Hermann
attempt to understand complementarity in the light of neo-Kantian ideas. As von Weizsäcker puts it many
years later, “The alliance between Kantians and physicists was premature in Kant’s time, and still is; in Bohr, we begin to perceive its possibility”. A series of modern scholars (Folse 1985; Honner 1982, 1987; Faye
1991; Kaiser 1992; Chevalley 1994; Pringe 2009; Cuffaro 2010; Bitbol 2013, 2017; and Kauark-Leite 2017)
has also emphasized the Kantian parallels. Although these scholars find common themes, they also disagree
to what extent Kantian or neo-Kantian ideas can be used as spectacles through which we may vision Bohr’s
understanding of quantum mechanics. On the other hand, Cuffaro (2010) holds that any proper
“interpretation of Bohr should start with Kant”, and that “complementarity follows naturally from a broadly
Kantian epistemological framework.”
(Copenhagen Interpretation of Quantum Mechanics)


“After discussions with Weizsäcker and Hermann in Leipzig in the 1930s, Heisenberg attempted to ground his interpretation of quantum mechanics on what might be termed a 'practical' transformation of Kantian philosophy. Taking as his starting point, Bohr's doctrine of the indispensability of classical concepts, Heisenberg argued that concepts such as space, time and causality can be regarded as 'practically a priori', in so far as they remain the conditions for the possibility of experience and even of 'objective reality', though they are not universal and necessary in a strictly Kantian sense.”(Heisenberg and the Transformation of Kantian Philosophy)

That quote isn't saying that Bohr was influenced by Kant. It's just saying people have noticed parallels. Wherever those parallels may be, the fact remains that there is no thing in itself in the Copenhagen interpretation. It's actually 100 times more bizarre than anything Kant ever thought up.

The idea that we can learn about reality by examining a priori conceptions of time and space is Einstein. If Heisenberg echoed that sentiment, it doesn't indicate Kantian influence.

And science clearly is not unified. We have broken it down into a hierarchical list of different sciences depending on scale and principle of organization. There have been long discussions of that hierarchy here on the forum. I think the important message is that reductionism works - each higher level behaves consistently with the level below - but constructivism doesn't - you can't generally predict behavior at a higher level from principles of the lower level. Example - you can't predict the behavior of biology from chemistry. — T Clark

:100: :fire:

Here, look at me being helpful to you: — frank

Now look who's talking down ... Projection is a hell of a drug. :roll:

Now look who's talking down ... Projection is a hell of a drug — 180 Proof

I'm a hypocrite. Shoot me.

Reread my last post in which I quoted your hypocrisy.

Reread my last post in which I quoted your hypocrisy. — 180 Proof

Yeah?

That quote isn't saying that Bohr was influenced by Kant. It's just saying people have noticed parallels — frank

It says that and also speculates on “a direct Kantian influence on Bohr”. So it is suggesting both. And I would suggest that those quoted believe the parallels between Kant and Bohr are close enough that it really doesn’t matter whether Bohr ever read Kant. The point is that these authors believe there is strong overlap in their ideas. You apparently disagree.

It says that and also speculates on “a direct Kantian influence on Bohr”. So it is suggesting both. — Joshs

Didn't exactly demonstrate that, did it?

The point is that these authors believe there is strong overlap in their ideas. You apparently disagree. — Joshs

Kant suggested we're creating that which we call reality. John von Neumann (I think more so than Bohr or Heisenberg) believed something similar. The reasons are pretty different though.

I just disagree that the Copenhagen interpretation can be characterized as an "assimilation of Kant.".

It says that and also speculates on “a direct Kantian influence on Bohr”. So it is suggesting both.
— Joshs

Didn't exactly demonstrate that, did it? — frank

I’ve been reading NIELS BOHR'S CONCEPT OF REALITY by Henry J Folse. He provides evidence that Bohr was an entity realist , a position that seems to represent a pre-Kantian form of realism.

“Natural phenomena, as experienced through the medium of our senses, often appear to be extremely variable and unstable. To explain this, it has been assumed, since early times, that the phenomena arise from the combined action and interplay of a large number of minute particles, the socalled atoms, which are themselves unchangeable and stable, but which, owing to their smallness, escape immediate perception. Quite apart from the fundamental question of whether we are justified in demanding visualizable pictures in fields which lie outside of the reach of our senses, the atomic theory was originally of necessity of a hypothetical character; and, since it was believed that a direct insight into the world of atoms would, from the very nature of the matter, never be possible, one had to assume that the atomic theory would always retain this character. However, what has happened in so many other fields has happened also here; because of the development of observational technique, the limit of possible observations has continually been shifted.

We need only think of the insight into the structure of the universe which we have gained by the aid of the telescope and the spectroscope, or of the knowledge of the finer structure of organisms which we owe to the microscope. Similarly, the extraordinary development in the methods of experimental physics has made known to us a large number of phenomena which in a direct way inform us of the motions of atoms and of their number. We are aware even of phenomena which with certainty may be assumed to arise from the action of a single atom. However, at the same time as every doubt regarding the reality of atoms has been removed and as we have gained a detailed knowledge of the inner structure of atoms, we have been reminded in an instructive manner of the natural limitations of our forms of perception.”
( Niels Bohr 1929)

He provides evidence that Bohr was an entity realist — Joshs

Could you explain what that means?

He provides evidence that Bohr was an entity realist
— Joshs

Could you explain what that means? — frank

"entity realism" asserts the real existence of unobserved entities.

“Entity realists think that when we accept a theory we have warrant for believing that the objects and events spoken of in nonobservational theoretical terms really do exist as the unobserved causes of observed phenomena; whereas antirealists hold that acceptance of a theory justifies no such belief.”

The fact they link to experiments and science sites and I just have your word. Most like this just reference the Wigner's Friend experiment.

https://qr.ae/pveiQl

This stuff too:

https://qr.ae/pveiQo

entity realism" asserts the real existence of unobserved entities. — Joshs

Oh. Think about Schrodinger's cat. That about sums up what the Copenhagen interpretation says about unmeasured entities. Today we say measurement doesn't have to involve a conscious entity. Did Bohr know that in 1929? I don't know. It's something that was established long after Bohr's time, but he may have had that intuition.

Sooooo you're saying Quantum Mechanics essentially says solipsism is true?

Sooooo you're saying Quantum Mechanics essentially says solipsism is true? — Darkneos

That's exactly right! What do I have to do to convince you that there's nobody here but me?!

The fact they link to experiments and science sites and I just have your word. — Darkneos

You don't just have my word, you have my argument, which I've made over my past posts on this thread. The heart of that argument is that the question of what reality is and whether or not objective reality exists is not a scientific question, it is a metaphysical, i.e. a philosophical, one. The answer to the question is in philosophy, not science. Scientists are not generally very good metaphysicians.

There's not much more I can say. If you don't get it or you disagree, there's no place else for this conversation to go.

Also - note the poster in the second Quora link you provided agrees with my position, although Quora is not generally considered an authoritative source. You'll find all sorts of inconsistencies and disagreements there.