Sunday, October 12, 2008
QM and the problem of Being
Here are some remarks on the practical implementation of the scientific paradigm. They sketch a semantic analysis of the reproducibility requirement and cast scientific results as rhetorical tools, with pointers for the deconstruction of some concrete examples, from the recent Gravity Probe B farce (arguably foreseen in , cf ,  also available at [3A]: "The gap between the current error level and that which is required for a rigorous test of a deviation from GR is so large that any effect ultimately detected by this experiment will have to overcome considerable (and in our opinion, well justified) skepticism in the scientific community", ) to my old favorite univalence superselection (, ,  ) all the way to a deconstructed notion of physical law (). The starting point is this sentence from Plato's Sophist, which famously inspired Martin Heidegger as well as others in his wake: "For manifestly you have long been aware of what you mean when you use this expression 'being'. We, however, who used to think we understood it, have now become perplexed". The inability/unwillingness of contemporary scientific thought to tackle the postulate of existence is arguably the core problem in quantum mechanics' "unfinished revolution". Without a deconstruction of the "a priori" semantic assumptions hidden in (our "scientific" image of) the world, the way ahead, beyond pirouettes in front of blatant experimental failure, will stay blocked. While such a deconstruction has been initiated by the relational approach to quantum mechanics, both its scope and its impact are still limited. Within RQM's epistemic framework one can recover some of the far-reaching arguments by Philip Warren Anderson against the reductionist approach. The mantra that "big things are made up of small things" is often tacitly assumed in scientific models. In a RQM perspective there are no things, either big or small, but only measurement outcomes/perceptions relative to a measurement operator. If this post didn't put you too sleep, there is more below.
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What about Penrose's theory of QM "macroscopic" and "microscopic" worlds? If confirmed by evidence, it would provide both an elegant liaison between quanta and gravitation and would define exactly what is subject to QM and what isn't.
By the way, has the crucial experiment devised by Penrose been done?
Thanks for your post. I have already commented elsewhere (see 1, 2) on Penrose's theory of gravity-induced collapse, which is
actually originally due to Diosi, as Penrose himsef duly acknowledges.
Superpositions that are arguably macroscopic have already been detected and I think it's only
a matter of time until superposed observers are detected. In general, since i regard quantum mechanics as an epistemic theory, I am skeptical about Penrose's ontologic approach. In my opinion
what is needed and what will emerge is indeed a relational quantum "theory of experience", even if turns out to be as troublesome as Penrose fears. Finally I vaguely remember Zeilinger suggesting that a table-top version of Penrose's experiment should be doable in the near future, but a quick websearch indicates that nothing concrete has come out of it yet.
About your article "Interference of macroscopic superpositions": has that experiment, or a similar one, been done?
I cannot believe to macroscopic superposition, but probably I would neither to microscopic superposition, had I been born in nineteenth century!
Thanks for your interest in my work. Superpositions (e.g. of electrical currents) that are arguably macroscopic have indeed been experimentally detected. Some of the relevant experiments are described and discussed by Anthony Leggett in the survey paper which I quote and reference in my post "Deconstructing decoherence" below. Detection of actual superposed cats and people at room temperature has not been experimentally realised yet. I am confident that it's just a matter of time.
I forgot that The Leggett paper is not freely available for download. However here are two links that should give an idea of the progress that has been made over the last few years.
Since I regard entanglement as an observer-dependent property of the measurement process, I disagree with the conceptual framework implicit in Zeilinger and Arndt's approach ( eg. when they state that 'The environmental state gets "entangled" with the quantum object, which means that information about the whereabouts of the object is rapidly disseminated into the surroundings'). The experiments described are relevant far beyond my objections, but I believe that the search for macroscopic superpositions is being hampered by erroneous theoretical views. In a nutshell, the whole "which path" pother arises from neglect of the unitarity breakdown that corresponds to measurement/perception.
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