I think a recap of our positions might be useful at this point.
We both accept that it is possible that there could have been infinite or near-infinite universes trying to come into existence before or at the same time as this one. We both accept that we have no evidence that this might be the case. We just do not know.
You believe that because we have no evidence for these other possible universes that this is therefore not science and is philosophy. You also claim that this invokes Occam’s razor by adding another tier of complexity that is not needed.
I looked up an exact definition of Occam's Razor from Wikipedia:
"The principle states that the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory."
If I say my explanatory hypothesis is that at the same instant as this universe came into existence there were near-infinite attempts at universes coming into existence all of which failed till this one, which did have the correct balance of values to allow it to exist, the universe is therefore not specially created. So this does not invoke Occam’s razor because this is a central part of the argument.
You could say that “this is not my theory” but then you have excluded a possibility that you agree is possible.
Occam’s razor is generally used where additional layers of complexity are added that doesn’t change anything like:
1/ God1 created the universe
2/ God2 created God1
3/ God3 created God2 – This could be continued to infinity...
None of the Gods have an explanation as to why they exist so adding 2/ and 3/ are unnecessary.
There are basic differences in the way you and I view things. I do not know Martin Rees. I have not read his book but undoubtedly he is a clever chap just as you are. However I do not give unsupported statements from him any credence unless it is supported by evidence and reasoning. So referring to what someone else in authority says means nothing unless it is supported by the full reasoning that led to their conclusions.
Fair enough – it was not to prove anything; merely quoting from a recognized authority. A professor of astrophysics and former Astronomer Royal, who knows a thing or two about the early universe and probabilities.
It doesn’t matter how qualified someone is; I wouldn’t accept a relayed statement from them as bolstering someone else's argument unless it was supported by reasoning.