Undergrad Deterministic wind down of the Universe under MWI or Copenhagen?

[entropy1]

Is it correct to say:

1. Under the Many Worlds Interpretation: If we rerun the universe repeatedly from the same state S(0), it winds down the same way each time, which is determinism;
2. Under the Copenhagen Interpretation: If we rerun the universe repeatedly from the same state S(0), it may well not wind down the same way each time, which is NOT determinism?

 

[.Scott]

With the Many-World Interpretation, rerunning the universe will give you the same set of states and the same set of "you"s. Since you don't get to choose which you is you, the determinism is pointless.

The Copenhagen Interpretation does not allow you to rerun the universe. That would be a duplication of quantum information which would violate the no-cloning rule.

 

[entropy1]

The Copenhagen Interpretation does not allow you to rerun the universe. That would be a duplication of quantum information which would violate the no-cloning rule.

I mean it as a thought experiment.

 

[.Scott]

I mean it as a thought experiment.

To answer in the spirit of the question, the Many-World interpretation is an interpretation and therefore should not be different from the Copenhagen interpretation. Both should result in the analogous results as far as determinism is concerned.

The basic problem is to create a testable definition for "determinism". If you can't do that, then this is philosophy.

 

[entropy1]

The basic problem is to create a testable definition for "determinism". If you can't do that, then this is philosophy.

Perhaps something like: suppose we have run R0 and run R1 under equal interpretation; IF an event occurs in one, it occurs in the other?

And as I mean it as a thought experiment, it should only have to be formally testable right? Kind of if you can show that X and only X happens for that particular starting state S and interpretation I.

 

[.Scott]

Perhaps something like: suppose we have run R0 and run R1 under equal interpretation; IF an event occurs in one, it occurs in the other?

If you can describe an experiment that could be performed in principle that would differentiate between MWI and Copenhagen, then MWI would become MWT (Many-Worlds Theory). By definition, an interpretation is simply a different way of describing the same experimental results.

That said, I am not convinced that MWI really is an interpretation. But I also believe I'm holding a minority opinion.

The trouble I have with MWI is that it creates what I might describe as "explosive dimensions". Super-positioning aside, you could describe your location in the universe with 4 values, three spatial dimensions plus time - with due considerations made for an origin and the non-Euclidean effects of gravity. But with MWI, you would need to look into every "split" that occurred in your historic light cone going back to the "beginning" and specify which branch you followed in each case. I predict that at some point Physics will include a more comprehensive way of keeping track of total information content, and at that point MWI will die. At a minimum, the main point of MWI was to avoid having to make a truly random choice - an act that would have added information to the universe. But its actual effect is the opposite because the content of each individual world is the ever-expanding "address" of that world.

And as I mean it as a thought experiment, it should only have to be formally testable right? Kind of if you can show that X and only X happens for that particular starting state S and interpretation I.

Yes. Within the limits of actual Physics, it has to be testable in principal. So an experiment involving three nearly identical black holes orbiting a common point would be fair game - even though it is doubtful such an experiment could ever be conducted. But requiring the universe to suddenly triple in mass would require you to explain how that could be within the limits of actual Physics.