Are there laws (axioms / principles / equations / inequalities) in physics that cannot be violated, no matter how slightly, by hand without leading to absurdities (singularities, inconsistencies)?
closed as too broad by Qmechanic♦ Jan 16 '18 at 21:50
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I don't think this question is really answerable, or at least the question is "everything can be violated to within experimental error" Like, I can even envision some theory where you don't have some notion of causality in the sense of, say, global hyperbolicity, but you recover it in some sort of classical limit.
In fact, I would argue, Newton's insistence on notions like this against Liebniz probably stymied the development of special relativity more than they otherwise would have without the sacred cow of Newton's global reference frame.