Full Idea
None of Newton's laws individually records anything that can be observed; it is only from combinations of Newton's laws that we can derive the measurable motions of bodies.
Gist of Idea
Newton's laws cannot be confirmed individually, but only in combinations
Source
Alexander Bird (Philosophy of Science [1998], Ch.2)
Book Reference
Bird,Alexander: 'Philosophy of Science' [UCL Press 2000], p.87
A Reaction
This certainly scuppers any traditional positivist approach to how we confirm laws of nature. It invites the possibility that a different combination might fit the same observations. Experiments attempt to isolate laws.