X-Message-Number: 14219
From: "John Clark" <>
Subject: Identity Of Indiscernibles 
Date: Tue, 1 Aug 2000 00:25:11 -0400

In #14207    Wrote:

    > Use common sens

Sounds like a fine idea, if it works.

    >the NY carbon could be included in an apple and the Boston one in coal :-)


OK, but to repeat my previous question, if I switched the carbon atom in coal 
with
a carbon in an apple how would things be different? Another example, I cool

your two atoms and bring them so close together that their positional 
uncertainty
overlap and a Bose-Einstein condensation is formed, the atoms merge identities.
Then I warm things up and I can see two atoms again, at this point what meaning
is there to ask which atom is which, even in principle?


     >[Physics 101 stuff deleted]  Waves are at the root of the uncertainty 
     principle.


It's more complex than that. The uncertainty is not caused by the wave, it's 
caused by the thing

that's waving. If it were just matter that was waving things could still be as 
deterministic as a

cuckoo clock, but that's not the case. The thing that's waving is the square 
root of a probability

not matter. And being a square root means it can and does have negative terms in
it and even

imaginary terms, and that means the quantum wave function is not a scalar like 
simple probability

but a vector with an intensity and a direction, and that means you can not just 
add up 2 independent

probabilities to figure the probability both will happen the way we usually do, 
and that means two

very different wave functions can yield the same probabilities, and that means 
we can't do things

the way "common sense" would dictate. And that's why the quantum world is so 
weird.


    >So that there is no uncertainty if there is no wave and there is no wave if
    there is not an
    >euclidean displacement.


I never said you can't know some things exactly, you can know with certainty all
the numbers

in one of Heisenberg's matrices for a particle, equivalently you can know the 
quantum wave

function of the particle exactly, but neither will let you know the position and
velocity exactly, and

that's not all, neither will let you know the exact energy of a particle and the
exact time it had it either.

    >I suggest you look at an elementary differential geometry book to
    >get some familliarity with these concepts.

Thanks for the advice but I don't believe I need to do that.

              John K Clark        

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