Undergrad MWI -- Infinite number of worlds?

[PeterDonis]

One conceptual/aesthetic/realism issue with MWI that arises for most of us relative laypeople is the notional continuous creation (to borrow an older term) of virtually infinite mass, energy and information at every decision point.

MWI does not say this happens. In MWI, the wave function is the reality, and there is only one wave function. It doesn't split. The appearance of multiple "worlds" comes from picking out particular terms in the wave function in some chosen basis and calling them "worlds". But there is only one wave function, and it always evolves unitarily in time, and unitary evolution can't create or destroy anything.

 

[Lord Jestocost]

Then it seems to me that MWI is really telling us that we can't say anything about the ontology of reality, right?

Yes! There is no single reality, which is essentially equivalent to no reality.

 

[Cten]

MWI does not say this happens. In MWI, the wave function is the reality, and there is only one wave function. It doesn't split. The appearance of multiple "worlds" comes from picking out particular terms in the wave function in some chosen basis and calling them "worlds". But there is only one wave function, and it always evolves unitarily in time, and unitary evolution can't create or destroy anything.

Helpful - thanks! First learned (a very little) about Everett and his work in the 1960s, and apparently been carrying around a distorted mental picture ever since.

 

[PeterDonis]

There is no single reality

This is not what MWI says. MWI says there is a single reality, and it is the wave function.