*From*: Michael Chase <goya@xxxxxxx>*To*: lit-ideas@xxxxxxxxxxxxx*Date*: Sun, 19 Dec 2004 10:25:18 +0100

Le 18 d=E9c. 04, =E0 20:03, Peter D. Junger a =E9crit : > > : > : However, I'm not sure how quantum physics 'quarrels' with the law of=20= > the > : excluded middle. > > I suspect that the reference is to the example of Schroedinger's Cat, > which is in a middle state where it cannot be said to be either alive > or dead. M.C. Yes, although quantum entanglement or superposition is of course=20 not restricted to cats. "According to quantum mechanics", writes Brian=20= Greene in The fabric of the cosmos (p. 82), "a particle can hang in a=20 state of limbo between having one or another particular quality". In=20 fact, particles exist in the form of a probability wave, which does not=20= "collapse" into an object with distinct properties until it is=20 measured. "When they are not being observed or interacting with the=20 environment, particle properties have a nebulous, fuzzy existence=20 characterized solely by a probability that one or another potentiality=20= might be realized" (p. 121). I'm sure Robert is aware of Hilary Putnam's work on quantum = logic,=20 which dates from the 1960's. In "Is logic empirical?" in R. Cohen and=20 M. P. Wartofski (eds.), Boston Studies in the Philosophy of Science 5=20 (Dordrecht, Holland: D. Reidel, 1968). Reprinted as "The logic of=20 quantum mechanics" in H. Putnam, Mathematics, Matter and Method,=20 Cambridge University Press (1976) he writes inter alia=A0: " =93Logic is = as=20 empirical as geometry. =85 We live in a world with a non-classical=20 logic.=94 > > Michael Chase (goya@xxxxxxxxxxx) CNRS UPR 76 7, rue Guy Moquet Villejuif 94801 France ------------------------------------------------------------------ To change your Lit-Ideas settings (subscribe/unsub, vacation on/off, digest on/off), visit www.andreas.com/faq-lit-ideas.html

**Follow-Ups**:**[lit-ideas] Re: Imagination and maths [and maybe more.....]***From:*Andreas Ramos

**References**:**[lit-ideas] Re: Imagination and maths [and maybe more.....]***From:*Peter D. Junger

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