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I just watched a YouTube video which explained that life as a sequence of events is a geometric object in the four-dimensional spacetime and that the future is not only predetermined, but it already exists. It then said that this is true only in flat spacetime, and that gravity may change things.

So, would gravity change the fact that the future is predetermined and fixed?

Thank you in advance for your response.

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  • $\begingroup$ I'm sorry I don't have time to watch the video (perhaps you could flag the time period of relevance in your post?), but perhaps theories related to superdeterminism are related to your interests? $\endgroup$ Commented Mar 11, 2018 at 23:28
  • $\begingroup$ There are an infinite number of futures, each with a probability, so the real question is how anyone can posit that only one of these is "pre-determined"? As a non-expert, I'd have thought quantum effects are more significant than gravity in creating divergent futures. $\endgroup$ Commented Mar 11, 2018 at 23:32
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    $\begingroup$ People have been making claims about pre-determination for a long time. Modern scientific views simply give them a new set of words to use in expressing the idea. $\endgroup$ Commented Mar 12, 2018 at 0:38
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    $\begingroup$ "...which explained that my life is an event in the four-dimensional spacetime" - then it's wrong right out of the gate; an event is a 'point' in spacetime. A particle that exists for some finite time necessarily has a world line, the locus of events that define where and when it is. $\endgroup$ Commented Mar 12, 2018 at 2:45
  • $\begingroup$ @AlfredCentauri Hey, thanks for the comment. I have edited the post and it now uses the exact wording of the video. You sound rather knowledgeable in the area. So is the future predetermined and fixed in general, or is it so only in flat spacetime? $\endgroup$
    – Hui Wang
    Commented Mar 12, 2018 at 3:22

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I just watched a YouTube video which explained that life as a sequence of events is a geometric object in the four-dimensional spacetime and that the future is not only predetermined, but it already exists. It then said that this is true only in flat spacetime, and that gravity may change things

This is a statement of somebody who does not believe in quantum mechanics. Quantum mechanics with special relativity has indeterminacy built in, rule of thumb: the Heisenberg uncertainty principle. It is not gravity that makes a change in a deterministic classical model even with four dimensions, it is quantum mechanics, the underlying level of all nature in present mainstream physics.

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By saying 'four-dimensional', the maker of the video is trying to posit that time itself is a dimension. Time, though, is of course merely a human concept and not a tangible element or force, much less an actual dimension.

Our lives are most likely not predetermined, as we can change our future with every tiny move we make.

Gravity and 'spacetime' can in no way affect our futures.

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    $\begingroup$ Time is not a spatial dimension, but why do you think it's not a dimension in the broader sense? $\endgroup$ Commented Mar 11, 2018 at 23:22
  • $\begingroup$ Gravity can most certainly affect our future. Without gravity, we'd careen off into the cold of interstellar space, far away from the life-preserving warmth of the sun. $\endgroup$
    – Chris
    Commented Mar 11, 2018 at 23:48
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    $\begingroup$ Time is most certainly a dimension. It is part of the makup of spacetime. We move through time in one direction, forward. Just like you can move through space. $\endgroup$ Commented Mar 12, 2018 at 2:49

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