Does quantum physics contradict B theory of time( or any other version of eternalism)? If it contradicts, then is it possible that B theory of time( or any other version of eternalism) is still applicable in the domain that concerns our everyday experience but it is not applicable in quantum scale?


Contrary to some of the comments given above, quantum theory does involve a theory of time. Time is often used as a parameter labeling the set of states of a quantum system, but this is problematic because time is measured using clocks which are physical systems. So quantum theory is incomplete without a theory of time and clocks.

A quantum theory of clocks was proposed by Don Page and William Wootters in 1983 and has been improved since then:


The short version is that quantum mechanics implies the existence of other universes and any given time is a special cases in the set of universes universes that contains records of previous times but not future times. See the paper above and chapter 11 of "The Fabric of Reality" by David Deutsch. As such, all times exist. They don't go in and out of existence. This sounds somewhat like the b theory of time.

  • Properly understood, quantum theory is about the nature of time and has substantive implications for the nature of time that are different from other theories as explained in my answer. – alanf Oct 17 '17 at 13:25
  • "Properly understood" according to whom? The Montevideo interpretation that you are pushing is a small minority opinion listed under "Other" on the list of minority opinions. Quantum mechanics "implies" no such things, these are conjectures that may or may not work out. Moreover, even according to the paper you linked "this is the timeless approach to time", so "all times exist" is at best misleading, one might as well say "time is an illusion". Especially since it is an artefact of choosing a clock. – Conifold Nov 9 '17 at 20:21
  • The actual implications of an idea are independent of what people think about that idea. So your question uses a false assumption. You also haven't made any specific criticism of the content of the paper. All knowledge is conjectural, so you're "it's a conjecture" objection has no teeth. The "timeless approach" just means that time is an emergent consequence of internal features of the multiverse, not that there is literally no such thing as time. The paper also restricts clock choices: they're not arbitrary. Also, the paper I cited is not about the montevideo interpretation. – alanf Nov 10 '17 at 23:37
  • There is no such thing as "actual implications of an idea" except in formal systems or in the eye of the beholder. And SE is not a place for "specific criticisms", there are peer reviewed publications for that. When you present controversial ideas here please clearly state so and mention alternatives, do not misrepresent them as common knowledge. "All times exist" is equally non-literal, so you shouldn't be complaining, and the Montevideo interpretation is close enough by the precision "standards" of your post, after all it attaches time to internal clocks and conditions probabilities on it. – Conifold Nov 11 '17 at 0:01

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