# Are Newton's Axioms really axioms? [closed]

What is the absolute Logical origin of Newtons three axioms? Have physicists worked out what is the fundamental reason for actio = reactio and other things?

• There is no "logical origin" for axioms of physical theories. After all, physics is still an experimental science. – ACuriousMind Feb 24 '16 at 18:14
• and because it is experimental we have still to assume that These laws of mechanics come from god? – kryomaxim Feb 24 '16 at 18:16
• You can easily find papers and texts written on the topic of axiomatic mechanics; one random example that you may find interesting is arxiv.org/abs/1205.2326, "Foundations of Newtonian Dynamics: An Axiomatic Approach for the Thinking Student." No branch of physics is truly axiomatic, for it is all founded on experiment, and our "physical laws" are almost certainly approximations. – Peter Diehr Feb 24 '16 at 18:31
• Newton's laws aren't axioms. They are short hand notation for a large class of observations, but curiously you can't even make those observations here on Earth. To find a place where Newton's laws hold, you need, at least, a vomit comet or, better, a spacecraft in low Earth orbit. – CuriousOne Feb 24 '16 at 20:40

Without going into too much detail, Newton's first law tells us how to decide when we are actually in an inertial reference frame (This is the case if objects keep constant velocity if no net force is applied to them). The second law tells us what happens when we try to compare experimental results by two observers who are in different inertial reference frames. (e.g. the forces don't change because they are proportional to acceleration and the acceleration is the same in all the inertial reference frames. Therefore $F=ma$ holds good in every inertial frame.)