Mike McGuire wrote:

It's an elegant generalization but the concept wouldn't have arisen
without quite a few "crude" examples. In this particular instance, I
would say RW is talking about a different perspective on Newton's second
law.

Mike

I'm not dissing the incredible genius Newton, but the action principle
is far more general than Newton's Second Law. All three of Newton's
laws of motion can be derived from it, and it applies to modern
physics, both in the small and the large, in ways that Newton never
dreamed of.