I've been reading an excellent series on quantum physics the last couple of days. It's really helping me intuitively grasp some of the ideas there, at least as much as it's possible to intuitively grasp the quantum (i.e. real) world.
I've noted before that some people -- like myself -- feel liberated by an atheistic/scientific worldview, that it is simultaneously a relief (because the theistic worldview is so terrifying) and a sense of wonderment; whereas others -- like my wife -- while willing to accept the truth, feel a great existential disappointment about the whole thing.
One of the things Elezier's series pushes is that he is a proponent of the Many-Worlds hypothesis. All fine and good; in many ways I already found that the most reasonable of the many quantum interpretations (I wanted it to be the Hidden Variables hypothesis, but Bell's Theorem handily disposes of that). Still, it didn't particularly trouble me, because even if there would be an uncountable number of separate "me"s a picosecond from now, at this exact moment in time it still seemed there was one definite "me" -- perhaps with a gazillion twins in other alternate worlds, but there still seemed a certain subjective reality to the "now-me", even if there was no objective preference for this particular possible reality.
But Elezier's writings, in particular this post, has me now sort of discounting even the subjective reality of the instantaneous "now-me". It is difficult to put this into words... but somehow I was more or less okay with the thought of there being a single thread of "me-ness" hurtling through a vast space of possible histories, as opposed to the picture Elezier is painting in my head: That this idea of "possible histories" is itself an illusion, a hallucination brought about by the decoherence of various volumes of configuration space.
My mental image before was of a vast infinitesimally branching tree, an uncountable number of timelines springing out of each other, with parallel "me"s riding along each possible branch. Now I just see a static volume within an uncountable-dimensioned configuration space -- for which I might arbitrarily choose a cross-section and call that a subjective reality, but which doesn't exist independently of the rest of the configuration space in any sense whatsoever.
I guess, ironically perhaps, the most disturbing change in thinking is from a quantized tree of possible realities into a great smeared smudge of a single reality -- a reality that is sans even an instantaneously identifiable subjectivity. You could not take every "possible reality" and give it a serial number, and then choose a particular serial number and look up all of the serial numbers of the parent realities that led to it.
And that's the loss, I guess. I used to think that if I could pause reality and somehow "step outside of it" (this is a thought experiment, remember), that I could pick out one unbroken line of the infinite possible histories and say, "This is 'me', right at this moment, and this here is 'my past.'" It doesn't work that way. It's just one great big smudge. If I wanted to pause reality and "step outside of it", I couldn't just choose a point in configuration space and extract a "me" from it, I'd have to choose a compact volume of arbitrary size that hadn't yet decohered -- and even then that particular smeared-out "me" (which is already a much less satisfying "me" than an enumerated point would be) could not trace a line through configuration space -- or even a multi-dimensional tube throw configuration space, for that matter -- and say, "This was 'my past.'" "I" have no past. Just a big smear of quantum amplitudes.
Finally, that existential angst hits me. I'm going to go have some coffee; I may be nothing more than a smear of particles with no past and no future, but coffee still seems to taste good.
Addendum: Wow, the very next post in Elsevier's series deals with this problem of there being no "objective population count," as he puts it. GMTA or something. He's mostly dealing with it in showing that it is not a valid objection to the idea of decoherence, though. Still leaves me with the existential crisis. Jerk...
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