Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
Well, ANY physical concept is not more than a mental construct
Hmm. Is electrical charge a mental construct? Conservation of
charge is also a counterpart of a symmetry of Nature. Charge is,
somehow, a different sort of physical quantity than energy. For
example, the quantity of charge is independent of the frame from
which it is observed; the quantity of energy observed depends
upon the observer's frame. Charge is quantized; energy is not.
Charge is locally conserved; energy is not even localizable.
There are large qualitative differences between the concepts of
charge and energy. Charge is substantial; energy is insubstantial.
Whatever charge you mean, electrical or others, their conservation can be
interpreted as following a symmetry of some additional dimension (which may
be closed, to provide quantization?).
Leigh, let me explain myself. I
mentioned my reservation putting ("within the known limits"). Conservation
of charge is the first question which can be raised (and is discussed in
the supersymetry theory, I believe), but AFTER a great success of our
understanding of the origin for energy, momentum and angular momentum (in
classical theory) and parity (in quantum theory) to conserve. The open
questions regarding all other charges remain, meanwhile, out of a regular
curriculum, and occupy the minds of theoreticians. All this does not (for
me and I am quite sure, for the students) spoil the beauty of the emerging
picture. Just the opposite, it inspires an appetite for further search
for this elucidating connection: symmetry - conservation.
I believe that if your claim above is not trivial then it is not
correct, either.
I am sorry, Leigh, I do not follow your logic. I said that
symmetry-conservation law connection is a discovery of the twenties century
physics, which has not yet sufficiently used in introductory physics
courses. Not more than this. I did not intend to say anything more.
Well, ANY physical concept is not more than a mental construct
(see Dewey's aftermail quote of Einstein).
I'm told Einstein spoke German. I don't recall a German quote
following Dewey's signature.
No problem:
"Physical concepts are the free creations of the human mind and
are not, however it may seem, uniquely determined by the external
world."--A. Einstein in The Evolution of Physics with L. Infeld,
1938.