(Mar 23, 2024 09:32 PM)Magical Realist Wrote: [ -> ]Interview by Tom Casciato with Sean Carroll. Video available.
https://www.pbs.org/newshour/show/sean-c...l-there-is
"The "many worlds" theory in quantum mechanics suggests that with every decision you make, a new universe springs into existence containing what amounts to a new version of you. Bestselling author and theoretical physicist Sean Carroll discusses the concept and his new book, "Something Deeply Hidden," with NewsHour Weekend's Tom Casciato."
Max Tegmark, of course, favors the multiverse conception, too. Including more categories of parallel universes than just the Everett kind:
https://space.mit.edu/home/tegmark/multiverse.pdf
And that's what Tegmark's
mathematical universe hypothesis seems to have stemmed from. The simple
block-universe depiction of time can't accommodate a multiverse, so he had to expand to considering broader and more sophisticated mathematical structures than it:
https://arxiv.org/pdf/0704.0646.pdf
Even the conventional, specious "flow of time" itself is like a procession through the equivalent of a developmental sequence of parallel universes. That in the short term only incrementally differ from each other slightly at the subatomic level, but in the long run accumulate into differing significantly at the macroscopic level. It is their apparent arrangement that follows a developmental logic of a single cosmos progressing from a compact Big Bang state to the diverse complexity of today which drives the commonsense inference that it's always the same universe rather than "travel" through a chain of many different versions of it.
Such an analogy being a set-up for jumping to Julian Barbour's Platonia...
Addressed in the excerpt at bottom, Platonia (
The End of Time) is arguably an unconventional multiverse scenario (others like Lee Smolin have apprehended it as that). In Platonia, every possible configuration of the universe -- from primitive to complex -- resides in that mathematical structure. If time flowed in that structure (which it does not), then it would NOT follow a predictable, straight line through that sea of parallel universes, but instead wander along a crooked path of quantum probability.
In Platonia, the past that we each individually remember is actually just one path among a multitude of alternative, meandering routes that we might otherwise be personally concatenated with in terms of recall. The memory my brain features in a particular static universe configuration (or Now) is only going to include memories of prior brain states that it is consistent or compatible with. That's why the chain of events we remember seem organized or rational rather than random, disconnected, nonlinear, or crazy.
Each brain state of a human body in a specific Now is only cognitively concerned with itself (perception of only itself and the immediate environment). That is, in solipsistic style it only represents itself and the world of that particular Now as real, and regards those stored in its memory (the past) as not existing and those it anticipates in the future as likewise being non-existent. But in turn, another brain state in a different Now contains it as a disparaged part of its memory ("not real"), and thereby the two are -- in a sense, connected by that relationship.
The immortality that Barbour refers to, however, really isn't much different from that inherent in ordinary Eternalism. One difference is that in block-time everything is fixed (there's only one objective sequence of "parallel worlds" developing into each other), whereas in Platonia there may be multiple, quirky, alternative routes that speciously deliver one to what is apprehended as the current Now (which is "immortal" like all the rest).
From Here to Eternity
https://www.discovermagazine.com/the-sci...ternity-02
EXCERPTS:
Barbour is not alone in recognizing that the pictures of time in general relativity and quantum mechanics are fundamentally incompatible. Theoretical physicists around the world, spurred by Nobel dreams, sweat over the problem. But Barbour has taken perhaps the most unorthodox approach by proposing that the way to solve the conundrum is to leave time out of the equations that describe the universe entirely...
[...] Every possible configuration of the universe, past, present, and future, exists separately and eternally. We don't live in a single universe that passes through time. Instead, we— or many slightly different versions of ourselves— simultaneously inhabit a multitude of static, everlasting tableaux that include everything in the universe at any given moment. Barbour calls each of these possible still-life configurations a "Now."
Every Now is a complete, self-contained, timeless, unchanging universe. We mistakenly perceive the Nows as fleeting, when in fact each one persists forever. Because the word universe seems too small to encompass all possible Nows, Barbour coined a new word for it: Platonia. The name honors the ancient Greek philosopher who argued that reality is composed of eternal and changeless forms, even though the physical world we perceive through our senses appears to be in constant flux.
Before allowing himself to be interrupted by the stream of questions he knows will come, Barbour continues to press his point. He likens his view of reality to a strip of movie film. Each frame captures one possible Now, which may include blades of grass, clouds in a blue sky, Julian Barbour, a baffled Discover writer, and distant galaxies. But nothing moves or changes in any one frame. And the frames— the past and future— don't disappear after they pass in front of the lens.
[...] Don't we then somehow shift from one "frame" to another?
No. There is no movement from one static arrangement of the universe to the next. Some configurations of the universe simply contain little patches of consciousness— people— with memories of what they call a past that are built into the Now.
The illusion of motion occurs because many slightly different versions of us— none of which move at all— simultaneously inhabit universes with slightly different arrangements of matter. Each version of us sees a different frame— a unique, motionless, eternal Now.
"My position is that we are never the same in any two instants," Barbour says. "Obviously, as macroscopic human beings, we don't change much from second to second. And there's no question that we're the same people. I mean only an extreme madman would deny that," he says reassuringly. "To that extent, it's true that we do move from one Now to another. But in what sense can you say we're moving? The way I see it, not exactly the same information content, but nearly the same information content, is present in many different Nows." Nothing really moves, he says.
"The information content or the consciousness that makes us aware of being ourselves, of having a certain identity, is just present in many different Nows. There are two things that distinguish my position from what people might just intuitively think. First of all, the Nows are not on one timeline. They're just there. And second, there is nothing corresponding to motion. I'm taking a very radical position on that. I'm saying the Nows are really like snapshots. The impression of motion only arises because the snapshots have got an extraordinarily special structure." We are part of that special structure.
[...] Julian Barbour is convinced we are all immortal. Unfortunately, in a timeless universe immortality does not come with the same kind of perks that it does on Mount Olympus. In Barbour's vision, we are not like Greek gods who remain forever young. We still have to buy life insurance, and we will certainly seem to age and die. And instead of life after death, there is life alongside death.
"We're always locked within one Now," Barbour says. We do not pass through time. Instead, each new instant is an entirely different universe. In all of these universes, nothing ever moves or ages, since time is not present in any of them.
One universe might contain you as a baby staring at your mother's face. In that universe you will never move from that one, still scene. In yet another universe, you'll be forever just one breath away from death. All of those universes, and infinitely many more, exist permanently, side by side, in a cosmos of unimaginable size and variety.
So there is not one immortal you, but many: the toddler, the cool dude, the codger. The tragedy— or perhaps it's a blessing— is that no one version recognizes its own immortality. Would you really want to be 14 for eternity, waiting for your civics class to end?