4 ms·

That’s not an axiom, it’s an assumption. Anyway, it’s the assumption of isotropy.

• naasking 4y ago
  An axiom is an assumption: https://en.wikipedia.org/wiki/Axiom https://en.wikipedia.org/wiki/Axiom
  • qubex 4y ago
    It’s a matter of scope. Axioms are assumptions that undergird the formal edifice (those or mathematics or arithmetic) whereas assumptions are local to the theory. ‘Assumptions’ is a synonym of ‘postulates’. Axioms are foundational, such as m×n=m×n (which is true for scalars, but not true in general for matrices).
    • defined 4y ago
      Did you mean m×n=n×m?
      • HWR_14 4y ago
        Both are axioms. a = a (and by extension mxn = mxn) is another axiom.
        • goldenkey 4y ago
          Don't forget ©=©
      • qubex 4y ago
        Yes. Oops.
    • naasking 4y ago
      It's a distinction without a real difference. Calling an "assumption local to a theory" an axiom is fine. We have axiomatizations of both general relativity and quantum mechanics, for instance.
• deleted 4y ago
  [deleted]