From the time it came out, Zurek’s “Quantum Darwinism” always seemed like just a big muddle to me. Maybe he’s trying to obtain a conclusion that doesn’t actually follow from his premises; maybe he wants to call something an example of darwinism, when it’s actually not.
I don’t have time to analyze it properly, but let me point out what I see. In a world where wavefunctions don’t collapse, you end up with enormous superpositions with intricate internal structure of entanglement and decoherence—OK. You can decompose it into a superposition of tensor products, in which states of subsystems may or may not be correlated in a way akin to measurement, and over time such tensor products can build up multiple internal correlations which allows them to be organized in a branching structure of histories—OK.
Then there’s something about symmetries, and then we get to stuff about how something is real if there are lots of copies of it, but it’s naive to say that anything actually exists… Obviously the argument went off the rails somewhere before this. In the part about symmetry, he might be trying to obtain the Born rule; but then this stuff about “reality comes from consensus but it’s not really real”, that’s probably descended from his personal interpretation of the Copenhagen interpretation’s ontology, and needs philosophical decoding and critique.
edit: As for your own agenda—it seems to me that, encouraged by the existence of the “quantum cognition” school of psychology, you’re hoping that e.g. a “social quantum darwinism” could apply to social psychology. But one of the hazards of this school of thought, is to build your model on a wrong definition of quantumness. I always think of Diederik Aerts in this connection.
What is true, is that individual and social cognition can be modelled by algebras of high-dimensional arrays that include operations of superposition (i.e. addition of arrays) and tensor product; and this is also true of quantum physical systems. I think it is much healthier to pursue these analogies, in the slightly broader framework of “analogies between the application of higher-dimensional linear algebra in physics and in psychology”. (The Harmonic Mind by Paul Smolensky might be an example of this.) That way you aren’t committing yourself to very dubious claims about quantum mechanics per se, while still leaving open the possibility of deeper ontological crossovers.
Great points—I’m more-or-less on-board with everything you say. Ontology in QM I think is quite inherently murky—so I try to avoid talking about “what’re really real” (although personally I find the Relational QM perspective on this to be most clear—and with some handwaving I could carry it over to QD I think).
Social quantum darwinism—yeah, sounds about right. And yeah, the word “quantum” is a bit ambiguous here—it’s a bit of a political choice whether to use it or avoid it. Although besides superpositions and tensor products, quantum cognition also includes collapse—and that’s now taking quite a few (yes, not all!) ingredients from the quantum playbook to warrant the name?
Collapse can also be implemented in linear algebra, e.g. as projection onto a randomly selected, normalized eigenvector… Anyway, I will say this, you seem to have an original idea here. So I’m going to hang back for a while and see how it evolves.
From the time it came out, Zurek’s “Quantum Darwinism” always seemed like just a big muddle to me. Maybe he’s trying to obtain a conclusion that doesn’t actually follow from his premises; maybe he wants to call something an example of darwinism, when it’s actually not.
I don’t have time to analyze it properly, but let me point out what I see. In a world where wavefunctions don’t collapse, you end up with enormous superpositions with intricate internal structure of entanglement and decoherence—OK. You can decompose it into a superposition of tensor products, in which states of subsystems may or may not be correlated in a way akin to measurement, and over time such tensor products can build up multiple internal correlations which allows them to be organized in a branching structure of histories—OK.
Then there’s something about symmetries, and then we get to stuff about how something is real if there are lots of copies of it, but it’s naive to say that anything actually exists… Obviously the argument went off the rails somewhere before this. In the part about symmetry, he might be trying to obtain the Born rule; but then this stuff about “reality comes from consensus but it’s not really real”, that’s probably descended from his personal interpretation of the Copenhagen interpretation’s ontology, and needs philosophical decoding and critique.
edit: As for your own agenda—it seems to me that, encouraged by the existence of the “quantum cognition” school of psychology, you’re hoping that e.g. a “social quantum darwinism” could apply to social psychology. But one of the hazards of this school of thought, is to build your model on a wrong definition of quantumness. I always think of Diederik Aerts in this connection.
What is true, is that individual and social cognition can be modelled by algebras of high-dimensional arrays that include operations of superposition (i.e. addition of arrays) and tensor product; and this is also true of quantum physical systems. I think it is much healthier to pursue these analogies, in the slightly broader framework of “analogies between the application of higher-dimensional linear algebra in physics and in psychology”. (The Harmonic Mind by Paul Smolensky might be an example of this.) That way you aren’t committing yourself to very dubious claims about quantum mechanics per se, while still leaving open the possibility of deeper ontological crossovers.
Great points—I’m more-or-less on-board with everything you say. Ontology in QM I think is quite inherently murky—so I try to avoid talking about “what’re really real” (although personally I find the Relational QM perspective on this to be most clear—and with some handwaving I could carry it over to QD I think).
Social quantum darwinism—yeah, sounds about right. And yeah, the word “quantum” is a bit ambiguous here—it’s a bit of a political choice whether to use it or avoid it. Although besides superpositions and tensor products, quantum cognition also includes collapse—and that’s now taking quite a few (yes, not all!) ingredients from the quantum playbook to warrant the name?
Collapse can also be implemented in linear algebra, e.g. as projection onto a randomly selected, normalized eigenvector… Anyway, I will say this, you seem to have an original idea here. So I’m going to hang back for a while and see how it evolves.