Apr 8, 2025 07:00 PM
(This post was last modified: Apr 8, 2025 07:29 PM by C C.)
Einstein vs Bohr: Quantum reality is still up for grabs (philosophy of science)
https://iai.tv/articles/einstein-vs-bohr..._auid=2020
INTRO: For decades, the story went that Bohr’s anti-realism triumphed over Einstein’s quest for a deeper reality. Physicists were told to "shut up and calculate" and metaphysical debates were dismissed as distractions. But today, realist interpretations of quantum mechanics constantly emerge and the anti-realist position is far from the mainstream – so if Bohr won, why does almost no one take his side? University of Massachusetts Boston physicist Jacques Pienaar argues that we’ve been wrong all along – Bohr was not an anti-realist after all, and Einstein's apparent realism is not on sure-footing...
EXCERPTS: . . . You might be forgiven for thinking that realism is now dead, and anti-realism reigns supreme; but [...] In the vacuum left by realist theories, over the last few decades several new interpretations have emerged, using the tools of quantum information theory to transform the old Copenhagenism into something new. Humorously dubbed “Copenhagenish interpretations” by physicist Matt Leifer, the new contenders include, among others, neo-Copenhgenism, Relational Quantum Mechanics, and subjective Bayesian quantum mechanics – better known by its catchy moniker “QBism”.
[...] While they still toe the Copenhagen line that quantum states do not describe reality, they supplement it with a remarkable constructive claim: that physical quantities – such as specific values of properties like position or momentum – only exist in relation to the observer who measures them, and a quantity value that exists for one observer may not exist for a second observer, if the latter performs a different, “incompatible” measurement (Pienaar 2021). Reflecting on this on that rainy day, I wondered: what if the real story behind the Bohr-Einstein debates was more complex than just ‘realism’ versus ‘anti-realism’?
Einstein [...] explained to a colleague, “I do not feel comfortable and at home in any of the ‘isms.’ It always seems to me as though such an ism were strong only so long as it nourishes itself on the weakness of its counter-ism; but if the latter is struck dead, and it is alone on an open field, then it also turns out to be unsteady on its feet”. In this quote, I think, we see the real reason for Einstein's distaste for Copenhagenism: he saw it as a purely negative program, defined only by its rejection of ‘realism’, without anything constructive to say about the latter term.
But just how ‘anti-realist’ was Bohr? He had, after all, consistently maintained that atoms were real, despite their not being directly observable to the senses [...] Bohr’s ‘realist’ tendencies often get overlooked ... Would Bohr really have disowned his intellectual descendants, if he’d known how boldly they now sought to make positive claims about ‘reality’? (MORE - details)
https://iai.tv/articles/einstein-vs-bohr..._auid=2020
INTRO: For decades, the story went that Bohr’s anti-realism triumphed over Einstein’s quest for a deeper reality. Physicists were told to "shut up and calculate" and metaphysical debates were dismissed as distractions. But today, realist interpretations of quantum mechanics constantly emerge and the anti-realist position is far from the mainstream – so if Bohr won, why does almost no one take his side? University of Massachusetts Boston physicist Jacques Pienaar argues that we’ve been wrong all along – Bohr was not an anti-realist after all, and Einstein's apparent realism is not on sure-footing...
EXCERPTS: . . . You might be forgiven for thinking that realism is now dead, and anti-realism reigns supreme; but [...] In the vacuum left by realist theories, over the last few decades several new interpretations have emerged, using the tools of quantum information theory to transform the old Copenhagenism into something new. Humorously dubbed “Copenhagenish interpretations” by physicist Matt Leifer, the new contenders include, among others, neo-Copenhgenism, Relational Quantum Mechanics, and subjective Bayesian quantum mechanics – better known by its catchy moniker “QBism”.
[...] While they still toe the Copenhagen line that quantum states do not describe reality, they supplement it with a remarkable constructive claim: that physical quantities – such as specific values of properties like position or momentum – only exist in relation to the observer who measures them, and a quantity value that exists for one observer may not exist for a second observer, if the latter performs a different, “incompatible” measurement (Pienaar 2021). Reflecting on this on that rainy day, I wondered: what if the real story behind the Bohr-Einstein debates was more complex than just ‘realism’ versus ‘anti-realism’?
Einstein [...] explained to a colleague, “I do not feel comfortable and at home in any of the ‘isms.’ It always seems to me as though such an ism were strong only so long as it nourishes itself on the weakness of its counter-ism; but if the latter is struck dead, and it is alone on an open field, then it also turns out to be unsteady on its feet”. In this quote, I think, we see the real reason for Einstein's distaste for Copenhagenism: he saw it as a purely negative program, defined only by its rejection of ‘realism’, without anything constructive to say about the latter term.
But just how ‘anti-realist’ was Bohr? He had, after all, consistently maintained that atoms were real, despite their not being directly observable to the senses [...] Bohr’s ‘realist’ tendencies often get overlooked ... Would Bohr really have disowned his intellectual descendants, if he’d known how boldly they now sought to make positive claims about ‘reality’? (MORE - details)
