this is my first question here so I hope I'm following the guidelines correctly. I recently found a relatively obscure physicist/philosopher who asserts that the concept of Many Worlds is tautologically true (Note: he specifies a concept of a Classical Many Worlds, which as far as I can tell is basically like modal realism). He has a series of articles talking about it, but I think the most bare-bones argument is most well-summed up by this article: https://www.science20.com/alpha_meme/modest_agnostics_expect_multiverse_and_hold_many_worlds_true-85038 and specifically this excerpt:
"A fundamental description aims to take account of the whole of totality, of all that is possible. If you refused Many Worlds in such a description, you will do the following ridiculous thing:
You would assume that in the very foundation of totality, the very most fundamental laws of nature, the absolute rock bottom core of physics in its most profound and general symmetries, there is something inside there that ensures that you, yes you personally with name and address, wear that silly color shirt today!"
I know that there's a similar genre of argument for the Multiverse involving the idea of fine-tuning, specifically the fine-tuning of the constants of the universe potentially implying that there are other universes out there with different constants or even different laws of physics. However, I believe the current stopping point of that debate is that we can't know for certain right now since for all we know, the constants are fundamental to a theory of reality or something.
However, this article asserts that even if the laws of our universe are fundamental, the initial conditions that led to the universe being the way that it is today is not, and therefore all initial conditions (i.e., initial conditions that lead to you wearing a different colored shirt) must be fundamental to reality, which argues in favor of Many Worlds.
I'm not a student of philosophy, I just read around, but as far as a quick Google search tells I haven't really seen this argument before. However, this scientist is by no means a well-established philosopher, so I'm curious to know whether or not there are other philosophers/philosophies out there that make this kind of argument, so that I could read more into it. Thanks!