I David Deutsch (1985) attempt to solve the incoherence problem

[jxcs]

Can anyone elaborate on Deutsch's attempt to solve the incoherence problem?

He postulates a continuously infinite set of universes, together with a preferred measure on that set. And so when a measurement occurs, the proportion of universes in the original branch that end up on a given branch is given by the mod-squared measure of that branch. Observers will then be uncertain about which outcome will occur in the universe they inhabit.

Is it just the case that as a result of this we can now *talk* of probabilities as we have introduced uncertainty? Whereas before it was simply the case that we cannot assign probabilities as all outcomes will definitely occur?

 

[Avodyne]

Yes, that is the idea. It has been developed Vaidman; see e.g.
https://plato.stanford.edu/entries/qm-manyworlds/#4.2

See also Carroll & Sebens,
https://arxiv.org/abs/1405.7907

 

[jxcs]

great, thanks!