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by DavidPlumpton 3679 days ago
The Everett FAQ makes even stronger claims about the status of Many Worlds. See http://www.hedweb.com/manworld.htm#interpretation
2 comments

Ah, why do these kind of Physics FAQ always claim to be objective and then obviously are not? This fact commits all the sins of the typical physics FAQ. For example it claim sthat only many-world is scientific, that other interpretation requires extra assumptions. It even labels Copenhagen as being "vitalist". It also does not address some very valid cristicisms:

1. Conservation of energy. 2. Relativistic observers seeing multiple decoherence events in different orders. 3. Experiments that affect whether a particule pair did decohere inthe past. (i.e. quantum state recombination.)

Basically, MW assumes that the probability wave exists and that all outcomes exist, which is a very big assumption, which that FAQ gloss over rapidly. (And then explictly call other interpretations' assumptions as a negative...)

> 1. Conservation of energy.

This is not a problem for MWI.

> 2. Relativistic observers seeing multiple decoherence events in different orders

There is no decoherence in MWI.

There is no decoherence in MWI.

Yes there is. Decoherence provides the theoretical framework to explain why the superposition of parallel observers can never meaningfully interact with themselves again, even though a superposition of simple particles can.

See https://en.wikipedia.org/wiki/Quantum_decoherence#In_interpr... for more.

That said, the order in which an observer notices decoherence events has no particular physical importance.

Why would a MW faq address criticisms of the Copenhagen interpretation?
That is just plain bombastic. It says "All the other theories fail for logical reasons." No reasons given. It has a link, but the very first section in the link says "Copenhagen Interpretation... not fatal, but unpleasant". Well OK, you don't like non-locality. That's not a real argument! And a bunch of the questions about linearity ignore the fact that gravity is clearly non-linear.