A bit of a technical comment, but something that also speaks against quarks as components, although also just another aspect of the confinement you mentioned.
Quarks "states" don't actually lie in the QCD Hilbert space, but technically only in a larger Krein space since they have negative norms. They are as such a "trick" to permit the use of local fields, since those give propagators with nice structures for Feynman graph evaluation in perturbation theory.
There's similar technicalities even with electrons where due to infrared issues electrons in QFT don't even have a well defined mass (two-point function has no momentum space pole).
As difficult as materialism/realism is in non-relativistic QM, it becomes even more so in QFT.
I just read your paper "Bohr, objectivity, and 'our experience'" on the arxiv. Together with your earlier work "Niels Bohr, objectivity, and the irreversibility of measurements" it's a very clear exposition of Bohr's writing.
It's actually both your own writing in those papers and of course Bohr's writings that pinpoint something I never found satisfying in the "decoherence/consistent histories" papers. Namely the attempt to describe the classical world emerging out off the quantum world, by showing various collective coordinate operators for macroscopic bodies (e.g. the position of a mote of dust) are effectively classical variables. This looks fine until one realises that these macro-operators are functions (usually weighted sums) of microscopic operators which themselves represent nothing more than possible quantum phenomena (in Bohr's sense) occurring in the common/shared macroscopic world. So it's really not emergence at all as you say on page six of the new paper.
A bit of a technical comment, but something that also speaks against quarks as components, although also just another aspect of the confinement you mentioned.
Quarks "states" don't actually lie in the QCD Hilbert space, but technically only in a larger Krein space since they have negative norms. They are as such a "trick" to permit the use of local fields, since those give propagators with nice structures for Feynman graph evaluation in perturbation theory.
There's similar technicalities even with electrons where due to infrared issues electrons in QFT don't even have a well defined mass (two-point function has no momentum space pole).
As difficult as materialism/realism is in non-relativistic QM, it becomes even more so in QFT.
Ulrich,
I just read your paper "Bohr, objectivity, and 'our experience'" on the arxiv. Together with your earlier work "Niels Bohr, objectivity, and the irreversibility of measurements" it's a very clear exposition of Bohr's writing.
It's actually both your own writing in those papers and of course Bohr's writings that pinpoint something I never found satisfying in the "decoherence/consistent histories" papers. Namely the attempt to describe the classical world emerging out off the quantum world, by showing various collective coordinate operators for macroscopic bodies (e.g. the position of a mote of dust) are effectively classical variables. This looks fine until one realises that these macro-operators are functions (usually weighted sums) of microscopic operators which themselves represent nothing more than possible quantum phenomena (in Bohr's sense) occurring in the common/shared macroscopic world. So it's really not emergence at all as you say on page six of the new paper.