From: Rakesh Bhandari (bhandari@BERKELEY.EDU)
Date: Wed Feb 28 2007 - 13:17:11 EST
>Hi Rakesh > >>But Ian is measurement always the passive ascertainment of a >>pre-existing property? > >Temperature exists independently of the length of the mercury column. >For example, temperature can be measured in other ways. > >Plus, the theoretical definition of temperature makes no mention of >thermometers or measuring devices. It's defined as a quantity >proportional to the average kinetic energy of molecules (or something >along these lines). > >If labour values are necessarily defined as a function of prices then >how can prices be a "form of value" or be their "measure"? > >Best wishes, >-Ian. On 18th May 2000 I sent to OPE-L this exerpt from David Lindley's Where does the Weirdness Go, a simple intro to quantum mechanics. The point is that measure does not seem to always be the passive ascertainment of a pre-existing property as it is with temperature. Paul C thought I was making mystical use of quantum mechanics but I was insistent about where the analogy to value measurement breaks down. I elaborated my use of the analogy later. Consider Lindsay's intro for the tyro: "In classical physics, we are accustomed to thinking of physcial properties as having definite values, which we can try to apprehend by measurement. But in quantum physics, it is only the process of measurement that yields any definite number for a physical quantity, and the nature of quantum measurements is such that it is no longer possible to thik of the underlying physical property (magnetic orientation of atoms, for example) as having any definite or reliable reality before the measurement takes place...[I]n quantum physics, it is only the conjunction of a system with a measuring device that yields definite results, and because different measurements (applying a Stern-Gerlach magnet with either up down or left right orientation, for example) produce results that, taken together, are incompatible with the preexistence of some definite state, we cannot usefully define any sort of physical reality unless we describe not only the physical system under scrutiny but, also and with equal importance, the measurements we are making of it. "This is no doubt baffling. We are through long familiarity grounded in the assumption of an external, objective, and definite reality, regardless of how much or how little we know about it. It is hard to find the language or the concetps to deal with a 'reality' that only becomes real when it is measured. There is no easy way to grasp this change of perspective, but persistence and patience allow a certain new familiarity to supplant the old."
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