The probability is equally distributed for every flip of the coin which is what matters and that only happens once every Sunday....for all Sundays in the world it will be 50/50. What we are conflating here are domains of perception and which one these distinct domains should we attribute the probability to...the kind of question that wonders about if Reality is perception dependent be it for pragmatical purposes or Ontological purposes. This is an old fight between phenomena and Noumena...and if for one it can awkwardly be argued that every phenomena is a noumena in itself (in common parlance a dream is a real dream if dreamed) for another there is no denying phenomena are by definition about differentiating domains but not about differentiating THE Reality with capital R!
Regarding the Multiverse the same principle applies, Reality is ONE, domains are many, and because I believe the central idea here is Reality not "Islands" the use of the wording Multiverse seems redundant even if useful for communication purposes..a Universe with many "islands" would be more appropriate...again the problem is with the constant misuse of the world Reality vs "non Reality", Everything vs Nothingness or the empty set being or not being an actual Set as if both concepts are equally valid in absolute terms...it just so happens that the idea of absolute Nothingness is phenomenological in nature, an illusion, a contradiction in terms as it is a linguistic misappropriation of partial absence (shadows or memories of things) and applying it to an Absolute which by definition includes Everything including phenomenological partial absences but never the absolute negation of the Whole itself as THINGNESS throughout ALL Spacetime, that is to ascertain Existence or Everything is Noumenological period! Now all this diatribe is important because when we are attributing probabilities to something we need to clarify if we are not conflating distinct domains in Set ordering, and evening out fields for probability calculus that do not match in spite of perception...
