Re: Data types in physics

J. J. Lodder wrote:

A trivial example is the maximal system of dimensions,
in which every physical quantity has its own dimension.

That would be the most general dimension system, in the sens that the
others arise by imposing some equivalence relations.

In theoretical physics, one may set c = 1, so all lengths can be
measured in seconds. So how about buying 20 ns (nano seconds) of rope?

That's of course just what we would do,
if we could start afresh with our unit systems.

I think one use say the charge of the electron as basic unit.

Backward compatibility does have it's claims however.

That is one reason. Another is the ability to measure the physical
constants. For example, mass, time and length can be measured to a
higher accuracy than the gravitational constant, making it unsuitable as
a conversion constant.

And in actual fact you are buying rope measured in nanoseconds,
it is just that you (and everybody else)
prefer to use some inconvenient numerical constants as well.

There is another factor: even though time and length can be treated as
the same in a physical theory, they have in practical experience quite
different characteristics. So giving them different dimensions is in
line with that experience.

Hans Aberg

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