I have heard the terms "law of nature" and "law of physics" used interchangeably, but is there any difference between them?


2 Answers 2


Law of nature, in the philosophy of science, a stated regularity in the relations or order of phenomena in the world that holds, under a stipulated set of conditions, either universally or in a stated proportion of instances.

So the Britannica

This is very abstract but it does cover all the "laws of physics" which are things like Newton's three laws of motion. Basically, a law of physics is a law of nature of the sort that a physicist would study. This is a large subset of the laws of nature and so gives many situations where they would be interchangeable.

Some are not. We still refer to Mendel's laws, but we would call them "laws of genetics" or possibly "laws of biology" even though they are laws of nature.

  • Would you say Newton's law of gravity is a law of nature? Or a law of physics? Newton's theory of gravity has been replaced by Einstein's general relativity, but we know it, too, is incomplete. Does that make general relativity a law of nature or a law of physics?
    – user4894
    Oct 25, 2020 at 20:00
  • 1
    I could use either because laws of physics are a subset of laws of nature.
    – Mary
    Oct 25, 2020 at 20:03
  • Didn't understand that. Was Newton's gravitation a law of nature up until 1915, when it became only a former law of physics? Can you clarify this please?
    – user4894
    Oct 25, 2020 at 20:36
  • Newton's laws remain laws, albeit "in a stated proportion of instances" -- namely, they continue to describe motion in all situations where relativity is negligible. Which is most of them. And all the laws are merely approximations. Even relativity.
    – Mary
    Oct 25, 2020 at 22:15

The question amounts to asking whether every phenomenon of nature falls under the jurisdiction of physics.

(1) Saying yes implies ( or seems to imply) a reductionist stance: one could argue that physical laws, though basic and fundamental, do not account for all sorts of natural phenomena ( for example biological phenomena).

(2) Traditionally ( since Kant) nature( realm of all phenomena) is divided into spatially extended nature ( studied by physics) and psychological phenomena ( taking place in time , but not in space). So, if there are actually psychological laws, these are natural laws, but not physical laws.

Reference : Kant, Critique of pure reason ( Theory of method).

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