- #1
AJ Bentley
- 668
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For some reason, I've seen several recent questions that can be answered by simply pointing to Newton's 3rd law (Action and Reaction).
Then I stopped to think. The first law is observational. We've all seen enough (sort of) practical verifications of things not stopping or refusing to start. So I think we can say it's an observed fact about the universe.
But the 3rd seems to me to be fundamentally unverifiable. It's a sort-of err... fact.
Does that mean it has to be downgraded to an assumption?
Newton's first assumption.![Devil :devil: :devil:](https://www.physicsforums.com/styles/physicsforums/xenforo/smilies/oldschool/devil.gif)
Then I stopped to think. The first law is observational. We've all seen enough (sort of) practical verifications of things not stopping or refusing to start. So I think we can say it's an observed fact about the universe.
But the 3rd seems to me to be fundamentally unverifiable. It's a sort-of err... fact.
Does that mean it has to be downgraded to an assumption?
Newton's first assumption.
![Devil :devil: :devil:](https://www.physicsforums.com/styles/physicsforums/xenforo/smilies/oldschool/devil.gif)
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