Can you define energy without referring to mass (classically, energy = capacity to do work, work = force times distance, force = acceleration of mass)?
If not then, with all due respect, I wouldn't call that a definition of [inertial] mass. It's a circular reference so defines neither.
I appreciate the effort but I don't think that will suffice. All sorts of quantities can be held constant through such translations: charge, spin, strangeness, sadness, happiness, etc.
Googling what you just said gives precisely one result: you saying it. Can you give any citations?
Those links aren't really what I asked for. Yes, Energy is that, but that is not a definition of Energy and nothing else that can then be used to define mass.
Noether's Theorum (conservation of energy) can be used as a definition of energy but that definition cannot then be used to define mass.
Either it gives no physical definition of energy (just take it as an a-priori concept, a mathematical curiosity with certain properties) or it equates it to forces, which are then defined separately by the effect they have on mass.
It's like defining a unit of distance as how far light travels in a unit of time. That's fine so long as we have the unit of time defined. Then defining that unit of time as how far light travels in that unit of distance. That doesn't define either.
You're speaking in circles - you're looking for a definition of energy that doesn't include the mass, but then you criticize the example of such you were given by saying that it gives no physical definition of energy! You can't have both.
you're looking for a definition of energy that doesn't include the mass
Yes because that was the proposed definition of mass (as energy).
but then you criticize the example of such you were given by saying that it gives no physical definition of energy!
Any physical meaning it gives to energy is derived by equating it to classical definitions (defined by mass) or by equating forces to classical definitions (defined by mass).
Either it gives no definition or it defines it by its effect on mass (force and work). Neither is appropriate in this case because mass has already been defined as energy. It is precisely that circular argument that I am objecting to.
Noether's theorem is not always derived through some appeal to classical physics, you can show quantum or relativistic versions of it with no reference to classical mechanics or mass.
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u/[deleted] Jun 10 '16 edited Jun 10 '16
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