Exorcist

JKSCHW at aol.com JKSCHW at aol.com
Fri Sep 22 19:56:19 PDT 2000


In a message dated 9/22/00 8:23:40 PM Eastern Daylight Time, CharlesB at CNCL.ci.detroit.mi.us writes:

<< Yes, the uncertainty, the act of measuring changes the thing measured. And I know it has resulted in some people considering that this is something unknowable in principle.

But there seems to be some impatience here to me. In the history of science there have been a number of mysteries that remain mysterious for a longer time than has quantum mechanics. I don't see where it is warranted ( one of your favorite words :>)) to conclude that the quantum mechanics puzzle will never be solved or can never be solved.

>>

It is one of the embarassments of Einstein that he could not bring himself to accept quantum mechanics, which is inherently probabilistic. It was the probabilistic nature of QM, rather than Heisenberg's uncertainty principle, that bothered old Albert. Einstein was a metaphysical determinist--relativity theory, like classical mechanics, is deterministic. But this has to do with being able to specify the end state of the system if you you know the beginning state and the laws, The Uncertainty Principle, which is not the only basis of the probabilistic character of QM, means among other things that you can't specify the beginning state.

But QM also tells us that there are inherently probabilistic processes, that at the bottom all we can say about whether a uranium atom will decay in certain time is that it will with a probability of n, whatever the value of n may be. We can compute that value to a lot of decimal places. But that's all we can do. Two identical U atoms may be such that even in the same circumstances, in a the same period, one will decay and other will not.

Of course QM might turn out to be wrong. We must be fallibilists about it as about everything. But right now, nothing whatsoever suggests that it is. On the contrary.It is massively confirmed. We can be far more confident of it than of most of what we know. The maths of QM show that the puzzle in the Uncertainty Principle is not epistemological. It is not just that we don't know, or might know if we were small enough to get down there are look, or something like that. It is logical. Positing that we can simultaneously determine the velocity and position of a particle leads to mathematical contradictions. Likewise with the other probabilistic features. They goa ll the way down. It's not that if we knew more we could know for sure whether thr U atom would decay in a certain time.

That's the least of it. QM is so bizarre that it is really hard to wrap your head around what is supposed to be going on at the quantum level even if you can derive the theorems and confirm your results by observations. That is why Bohr's "Copenhagen interpretation," an antirealist metatheory of QM, has a lot of plausibility. Reality may not only be queerer than we suppose, as J.D. Bernal (a Marxist) once said, it may be queerer than we _can_ suppose. QM is the main instance of that. I don'ts ee why science has to presuppose that the world is intelligible to our finite understandings and imaginations, just that there is order there that we can find by empirical investigation.

--jks

--jks



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