[removed]

These are questions that I’ve been asking AI recently.

For what it’s worth science theory versus science fact is where it’s at presently so choose a rabbit hole to jump down and see what you can take away and apply to your question. Good luck

Looking at it like the multiverse splitting with ever decision seems a little anthropomorphic to me. I'm certainly not a physicist but I figure it's closer to how quantum uncertainty works, like an electroc being theoretically anywhere in a certain energy level around an electron. So you've got all this quantum soup sploshing around and we only really observe one possible configuration of it. Maybe all of the others possible exist at the same time, but only one is our "real" universe because that's what we observe.

[removed]

That's how my uneducated brain sees it. It's like if all possible outcomes are just probabilities on a bell curve, and we're sat somewhere on top of the bell, but the infinite possibilities stretch out at each end infinitely.

However this bell curve is in 3D space and might be better thought of as a gradual blurring, as more possibilities spread out from a single fixed point of observation.

In the many-world theory, actually, human choices are not the cause of "splitting", but wave functions collapsing (probably involved in human choices too).

>That theory would prove that you could go back in time between universes.

Well, no, because then you'd have to know how to find that other universe.. and if you could find that, then you could find any split of the infinite number of universes and pick the one that suits you most, but then there would already exist a universe where that happened and likely you are already in it.

And if you can find these universes, what is stopping you from finding the infinite number of universes that hold that future by all possible decisions that can be made?

Imagine the universe we're in as a timeline, and that timeline splits at the point of every potentiality, and from each of those points in the timeline a new actuality takes its own course.

If you were to try to travel backwards in time, along your current timeline, you would necessarily be introducing a new timeline altogether. By going backwards, you've made an alteration, causing a retroactively separate timeline. The past has already happened and can never be re-experienced in exactly the same way, because to experience it would necessarily change it into a new timeline, you see?

you can not jump between universes because a universe is by definition not connected to any other universe. uni means one. we can not escape our universe for a number of reasons, but a big one is the period of inflation following the big bang when our universe expanded at a rate exponentially faster than the speed of light which makes it impossible for us to ever travel to its edge, let alone beyond it. but even if you could escape our universe to jump into another, why would that have anything to do with time travel? you are talking two totally different things. but lets say you also have a time machine that you brought, you would quickly discover another problem, there is an infinite number of universes in the multiverse so unless you know which one you are going to and when it fractured from the one you are in, how would you ever know where and when to go? there is an infinite number so how do you even start to map that out? if you traveled to a universe that split back at the beginning of time, there would be no guarantee that earth would even exist. in fact, the multiverse would be full of empty universes where gravity was not strong enough to pull the first hydrogen atoms together to form the first stars, or inflation happened at a faster rate and the first stars were not able to coalesce, or the matter / anti-matter balance was different so there is no matter at all, or only anti-matter remains. and one last thing to consider, time is not a constant, it is speed up and slowed down by gravity amongst other things and in fact, time may not exist at all, it may simply be a byproduct of the motion that our universe is in with the motion creating the illusion of time to an observer.

Incorrect. The Many Worlds interpretation directly posits that collapse never actually happens; instead all wave functions are equally likely to occur, somewhere. This is the core pillar of the entire concept - that the wave function is real and that we should trust what the logical evolution thereof tells us.

The Everettian argument is that wavefunction collapse is a concept of human arbitration, and that it has never been observed in nature. In fact, experiments have managed to put ever larger systems into states of superposition. Instead of collapse, modern Everettians suggests the observed becomes entangled with the observer, which in turn results in the given amplitude, but alternative states of observation also exist - perhaps in some speculative multiverse of inflatory cosmology.

Yes, you are totally right. I was only trying to simplify the concept. Thank you for the clarification!

This the speculative hypertemporal hypothesis, that posits an alternative temporal direction, that would somehow be angular to past-present-future of the entropic block universe. Nothing of the sort has ever been observed or experimentally suggested or demonstrated. It's a purely philosophical contention at this point in time.

Everett's argument was simply that the wave function is a real feature of the natural world, and that alternative states of a given amplitude ought also exist somewhere. There are, in turn, multiple interpretations of this interpretation.

It might also be that alternative amplitudes exist in other worlds of some inflatory multiverse beyond the cosmic horizon - in which case, the evolution of the wavefunction remains purely deterministic within our own block universe. Thus, free will and human decision-making need not apply. Everett himself was determinist in his thinking, and the beauty of his interpretation is that it's entirely consistent with observation.