I know this thread has lain dormant for a day, but I want to have another go at it, having just read your excellent reply in the ‘consistent materialism’ thread (along with the video which was hilariously on-point).
I think it is well documented that the debate between Albert Einstein and Neils Bohr was about scientific realism. Even the Wikipedia article Bohr-Einstein debates reflect this fact:
Einstein’s refusal to accept the (quantum) revolution as complete reflected his desire to see developed a model for the underlying causes from which these apparent random statistical methods resulted. He did not reject the idea that positions in space-time could never be completely known but did not want to allow the uncertainty principle to necessitate a seemingly random, non-deterministic mechanism by which the laws of physics operated.
Einstein himself was a statistical thinker but denied that no more needed to be discovered or clarified. Einstein worked the rest of his life to discover a new theory that would make sense of quantum mechanics and return causality to science, what many now call the theory of everything. Bohr, meanwhile, was dismayed by none of the elements that troubled Einstein. He made his own peace with the contradictions by proposing a principle of complementarity that assigns properties only as result of measurements.
From the book I cited upthread, Quantum, Majit Kumar:
At the core of Einstein’s physics was his unshakeable belief in a reality that exists ‘out there’ independently of whether or not it is observed. ‘Does the moon exist only when you look at it?’ he asked Abraham Pais in an attempt to highlight the absurdity of thinking otherwise. The reality that Einstein envisaged had locality and was governed by causal laws that it was the job of the physicist to discover. ‘If one abandons the assumption that what exists in different parts of space has its own independent, real existence,’ he told Max Born in 1948, ‘then I simply cannot see what it is that physics is meant to describe.’
Kumar, Manjit. Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality (p. 352). (Function). Kindle Edition.
So, irrespective of which ‘interpretation of qm’ one accepts or even if none of them, then can we agree that the Bohr–Einstein debate was in large part about scientific realism, defined in terms given in the last of the above quotes.
Yes. But one thing I have tried to show is that ‘realism’ is so deeply ingrained in us that quantum physics cannot challenge it without falling into contradiction (taking the evidence as true [realism] and then denying scientific realism). At this point, realism can only be challenged through deep philosophical reflection.
and also notice Einstein’s very specific requirement - that physics requires the complete description of entities separated in time and space and from the observer.
it’s the fact that qm seems to challenge those tenets that is the cause of his concern.
The point is that I don’t believe quantum physics poses a challenge to realism in general. I believe that realism is challenged from other angles, i.e. relativism, pragmatism, idealism, scepticism, etc. Don’t get me wrong, I am not a realist, at least not in a naive sense, but I cannot accept that quantum physics poses a challenge to realism if it falls into a contradiction such as the one I have described.
I would say that Einstein had a naive understanding of realism. Consequently, he believed that quantum physics posed a problem for it. But in reality, I believe that quantum physics does not pose a problem for Einstein’s view. That is to say, Bohr continued to believe in the evidence presented by quantum physics as a description of the world, just as Einstein did. We can therefore say that the whole debate is based on a pseudo-problem caused by naive quasi-philosophical assumptions.
No, it’s not a pseudo problem, and it’s very bold to suggest that you understand Einstein’s realist objections better than he did himself.
But did he? The characteristic attitude of the Copenhagen interpretation:
What we observe is not nature itself, but nature exposed to our method of questioning ~ Werner Heisenberg, On Physics and Philosophy, 1958
From Neils Bohr:
Physics is to be regarded not so much as the study of something a priori given, but rather as the development of methods of ordering and surveying human experience. In this respect our task must be to account for such experience in a manner independent of individual subjective judgement and therefore objective in the sense that it can be unambiguously communicated in ordinary human language ~ Neils Bohr, “The Unity of Human Knowledge” (October 1960)
Note that while we must account for such experience independently of ‘individual subjective judgement’ , that what is being ordered and surveyed is still ‘human experience.’
What Quantum physics showed the scientists involved in the experiments is the limitations of the scientific method in determining the nature of our reality. Hence the problems thrown up by the Copenhagen interpretation.
It showed, or demonstrated that science had reached its limits of explanatory power, leaving the scientists trying to figure out something about the world which science was incapable of showing. And the more they thought about it, the more they realised that science is as much about coming up with a hypothesis (an intellectual act) and then trying to devise experiments to demonstrate it using the scientific method, as it is about pure discovery. This realisation also hints at the extent to which our world is actually in our heads (composed of highly complex neural processing by our brain, presenting our conscious self with a representation of a world out there), which brings into question the nature of the world out there.
I think of an analogy here, where I think of being a cat. A relative of ours which is only partly self conscious. When the cat is in the garden it is acutely aware of every movement and sound in the garden and it has an ability to move at lightening speed to catch a bird, or mouse. But it has no realisation of how it is able to do this, or what is required for an animal to do this. As far as the cat is concerned, it is a kind of disembodied consciousness (or being) experiencing the sights and sounds of the garden and able to move around it at will. To pair it down even more, there is only this consciousness and the mouse. The consciousness focuses so much on the mouse that all it is aware of is the mouse and how it moves. It has no other conscious brain activity. There is a lot of unconscious activity going on to enable the cat to do this, but the cat is entirely unaware of any of it.
So the quantum physicist is like the cat, just a consciousness and a sub atomic particle, which he/she is intensely focused on with the help of the scientific instrument. But to their dismay, they can’t quite focus on the mouse enough to determine which way it is facing and which way it will move next. They are so focused on this one sub atomic particle that they lose sight of all the other activity going on to enable it. A very complex apparatus and an intelligent brain, along with all the knowledge it has learnt and the cultural conditioning it has been given. It’s a kind of blindness, to everything except the mouse and suddenly they wake up with a start and realise that they are chasing their own tail.
To me, it’s a pseudo-problem at a philosophical level. Neither Einstein nor Bohr were philosophers (in the classical way), so their off-the-cuff philosophy has many flaws in its reasoning. We might ask, or in Bohr’s case: Does he accept the findings of quantum physics as true? Does he accept them as findings, in short? If the answer is yes, then he falls into the contradiction I have pointed out. It is like taking the evidence to argue that there is no evidence; Bohr does that, and that is why he falls into contradiction. It would be quite different if, in the first place, he did not believe in the findings of quantum physics as a true anti-realist, but he takes the evidence as something true and drawn conclusions from it. A naive move for a classical philosopher.