Not clear why this is a philosophical implication. Would an empirical result EVER answer a mathematical question?
Nick -----Original Message----- From: friam-boun...@redfish.com [mailto:friam-boun...@redfish.com] On Behalf Of Bruce Sherwood Sent: Thursday, July 07, 2011 8:20 PM To: The Friday Morning Applied Complexity Coffee Group Subject: Re: [FRIAM] The Grand Design, Philosophy is Dead, and Hubris I'm a physicist, not a philosopher, and I know very little formal philosophy, but I think in this case what Zeilinger claims is correct, that measurements have ruled out certain "philosophical" viewpoints on reality. The specific instance is roughly this (though I hasten to say that I am not an expert on the new perspectives on quantum mechanics, nor as I've said knowledgeable in philosophy): A possible view of microscopic reality is that some particles "have" a state, only probabilistically determined to be sure, but they have some state, and an observation determines what that (probabilistically determined) state is. This view of reality is truly ruled out by recent experiments, which show that the particles do NOT "have" a state to be measured, it really really is the case that they take on a state in the process of measurement. This is highly counterintuitive. It's the part of quantum mechanics that Einstein could not accept. The famous Einstein-Podolsky-Rosen (EPR) paper of the 1930s proved that it you took quantum mechanics seriously you would lead to absurd predictions, including such things as a system of particles not already being in a state before being observed. Since the predictions are absurd, EPR concluded that the theory of quantum mechanics must be imcomplete. It was many years before experimenters were able to carry out experiments to explore these absurdities. When they did, they found that the absurd predictions of quantum mechanics are in fact what happens. It is a delicious irony that yet another contribution that Einstein made to the development of quantum mechanics was to prove that quantum mechanics cannot be right, thereby stimulating people to do the experiments to investigate the "absurdities". Bruce P.S. I'm now reading an excellent history of the development of quantum mechanics, "The Quantum Story" by Jim Baggott. Much of this is familiar, but even one of the tales previously unknown to me was worth the price of admission (only $10 in Kindle edition). When Bohr created the Bohr model of the hydrogen atom, in the early 1910s, before publishing he discussed his ideas with Rutherford. Rutherford, who cultivated an aw-shucks New Zealand country boy image but who was very smart, asked, "But if you say that the energy state can drop one, or two, or three levels, what determines which energy change the atom experiences? What about causality?" On Thu, Jul 7, 2011 at 4:21 PM, <lrudo...@meganet.net> wrote: > Bruce Sherwood writes, in relevant part: > >> On the other hand, I can recommend highly the popular science book >> "The Dance of the Photons" by Anton Zeilinger > [...] >> At >> one point in the book he appropriately celebrates measurements that >> quantitatively address certain aspects of reality that have long been >> major issues in philosophy (and physics). These recent measurements >> actually rule out some plausible philosophical stances with respect >> to reality. It's intriguing that a physical measurement could do that. > > Surely it's more than intriguing, it's impossible. Any measurement is > embedded in a theory (including, at a bare minimum, a theory about how > the device that performs the measurement functions); all that a > measurement can do (and it's quite enough, and sometimes--very likely > in this case--both intriguing and well worth celebrating), with regard > to a philosophical stance, is provide evidence (possibly, as you seem > to me to suggest here, categorical evidence) that the philosophical > stance S and the theory T in which the measurement is embedded are > incompatible (I want to say "incompossible" but I don't think I have > the proper credentials to use that word in public). > > That, at least, is what I think is the correct position to take, based > on what I've read (and come to believe) about the foundations of > measurement. But I'm neither a physicist nor a philosopher... > > Lee Rudolph ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
