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Re: What are "principles" in science?



I think the word law is generally used for a mathematical equation that
expresses a relationship between variables. Of course these terms are not
uniquely defined and there will be exceptions. But for sake of illustration
here are some examples:

Boyle's Law, Charles' Law, Newtons laws (F=ma, F12=-F21), Ohm's law

Laws do not even have to be true under all circumstances. The gas laws are
a good example.

I would almost classify the principle below as a definition. OTOH stating
that the number of molecules stays the same would be a conservation law.
One could then argue about Mach's principle as to whether it is a law, and
is NTN1 just really a principle and not a law, however history often trumps
semantic distinctions.

John M. Clement
Houston, TX


"A PRINCIPLE TO REMEMBER. In a chemical
change the atoms in substances are rearranged
to make one or more new substances. The result
is a change in composition."

Would it be appropriate to replace the word
PRINCIPLE by the word LAW?
Ludwik Kowalski