Multiverses

There are different kinds of multiverses. Somewhere, I think in his anthology, The Oxford Book Of Modern Science Writing, Richard Dawkins clearly differentiates between two theories of multiple worlds but I have not been able to find the relevant passage on looking back through the book.

However:

many universes might occupy the same space while vibrating at different rates or instead might occupy different spaces separated by intervals along a fourth spatial dimension;

universes might differ only in the course of events - in the outcome of every human choice and of every particle movement - or, more fundamentally, in the laws of nature.

We are used to the idea that what is fiction in one world might be real in another but might what is a mere belief in one world be true belief in another? Poul Anderson's Holger Carlsen converts to Catholicism after his return from the Carolingian universe in Three Hearts And Three Lions. There is a Heaven and a Hell in the parallel world of Anderson's Operation Chaos and a Norse mythological world in another universe in the sequel, Operation Luna.

The suggestion that the Resurrection might occur and that a hereafter might exist in one universe although not in another strains my willing suspension of disbelief almost to breaking point. Here, I differentiated between the premises of fantasy and of other genres but one kind of multiversal fiction can incorporate both.