Do you ever wonder why you’re you rather than somebody else? Maybe your best friend, maybe that person who seems to have it all that you’re painfully envious of? Maybe anybody and everybody? To answer that question philosophically, let me turn it around and say, how do you know you’re not?
For all you know, you could be. Maybe you’re just not aware of being any other given person from the vantage point you call your own mind/body/central nervous system. And likewise, from their vantage point, they’re not aware of being you.
Consider if you cloned yourself, or, say, if you had multiple selves in parallel universes (which you probably do—Many Worlds Theory is the interpretation of quantum mechanics that’s most popular among physicists because it’s the most sensical one*), but each instance of you is not aware of being each other instance of you, because your bodies/sensory organs/neural networks, which house your experiences, are physically isolated from each other.
Sure, in the case of the clone or the parallel selves, you happen to more or less share an identity with them (such as your name, memories, etc.), but similarity of identity exists on a spectrum of possibilities, and any place you’d draw the line between an identity being “you” versus “not you” is arbitrary, so the absolute truth is probably that there is no line.
So, to harken back to the start of the essay, you might be inclined to wonder, why weren’t you born as so and so—a completely different person who doesn’t even share an identity with you? Just the fact that you would wonder that means that you have no epistemic problem with the idea that your (fundamental) identity is broad enough to include their identity, or at least that the beingness behind their identity is the beingness behind your identity. And, according to the above reasoning about the relative isolation of bodies—which house your experience, memories, and everything else that gives you your sense of identity and makes you feel distinct—for all you know, you could have been born as them, or even as everyone, in addition to having been born as you, while not realizing it. So there’s no reason to assume a metaphysical separation either.
And, even more importantly, what could be the necessary actual, measurable/experiential difference between it being the case that you are simultaneously the other and that you’re not? If you can’t pin it down to any necessary experiential difference, how can you say there’s any logical/meaningful difference between the two scenarios/viewpoints? And if you can’t say that, it’s necessarily just as true that you are everyone else as it is that you aren’t.
* One reason MWI is the most sensical interpretation of quantum mechanics is that it does away with/explains away the convoluted, ill-conceived, essentially gratuitous “collapse of the wavefunction” that tends to confuse people into thinking it’s an actual process that happens.
Also, physicists know that several fundamental constants, such as the fine structure constant, had to be exactly as they are to a fraction of a percent in order for life to have evolved in this universe at all. To explain this without invoking some kind of creationism, we have to fall back on the strong anthropic principle, which requires the existence of a multiverse of all possible worlds.
Also, string theory posits many possible worlds, each with a different dimensional topology and even different laws of physics. String theory is largely regarded as an ivory tower theory because it’s so complex and makes no currently testable predictions that other existing theories don’t, and it’s also technically not one theory but a set of many, many possible theories that we don’t know which one is correct, but it does unite quantum mechanics and general relativity, and it also has its origins in a very valid observation that subatomic particles appear to vibrate in a way closely analogous vibrating strings.
Also, Stephen Wolfram, inventor of Mathematica and Wolframalpha.com, IQ 160+, has simulated what he calls ruliad space, which is the space of all possible self-modifying graphs according to all possible rulesets, and he’s observed in these simulations that quantum-mechanical and relativistic behavior naturally emerge from this space of all possible spaces, or more specifically from us as observers necessarily existing within specific slices of this space. https://writings.stephenwolfram.com/2021/11/the-concept-of-the-ruliad/
Oh, and not to mention that a metaphysics of “this specific reality exists (or the specific starting conditions that causally led to this reality initially existed), composed of the specific data it is/was composed of as opposed to unlimited other possible datasets, as a relatively tiny oasis amidst infinite nothingness, for no apparent reason” is a less intuitive/reasonable and parsimonious metaphysics than either “nothing ever existed or will exist” (which obviously isn’t the case) or “everything that could possibly exist exists ‘somewhere'” (which is the possible case of the two latter cases).
And I have a further argument for why everything that could possibly exist exists ‘somewhere’ in this essay under the bullet point starting with “Why does anything exist, as opposed to nothing?”, and also here.
But note that these arguments for a multiverse are meant somewhat tangentially: we really need the existence of all possible variations of the self to support the main points of this essay (the part above the horizontal rule).
