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> "If a physicist knows how the universe starts out, she can calculate its future for all time and all space." This seemingly innocent statement could render a

> "If a physicist knows how the universe starts out, she can calculate its future for all time and all space." This seemingly innocent statement could render a prolific discussion. Branching so many ways... Which one would you like to pick? Loss of simultaneity, from relativity theory [1] Consistent histories and probabilistic future prediction by quantum mechanics [2] Free will -- upfront this can sub-branch into biology, psychology, philosophy, artificial intelligence... [3] [4] [5] "The Best Way To Predict The Future Is To Create It", so if we can create stuff, then it's possible to (at least partially) predict the future? [6] Futurism or Future Studies [7] [1] https://www.bbc.com/reel/video/p04s223f/physics-suggests-that-the-future-has-already-happened https://www.bbc.com/reel/video/p04s223f/physics-suggests-tha... [2] https://quantum.phys.cmu.edu/CHS/histories.html https://quantum.phys.cmu.edu/CHS/histories.html [3] https://www.frontiersin.org/articles/10.3389/fpsyg.2013.00131/full https://www.frontiersin.org/articles/10.3389/fpsyg.2013.0013... [4] https://www.wired.com/story/algorithmic-prophecies-undermine-free-will/ https://www.wired.com/story/algorithmic-prophecies-undermine... [5] https://projects.iq.harvard.edu/predictionx/week-3-free-will-determinism-and-predictability https://projects.iq.harvard.edu/predictionx/week-3-free-will... [6] https://quoteinvestigator.com/2012/09/27/invent-the-future/ https://quoteinvestigator.com/2012/09/27/invent-the-future/ [7] https://en.wikipedia.org/wiki/Futures_studies https://en.wikipedia.org/wiki/Futures_studies

ccvannorman 5y ago
Exactly this! First, if all the initial conditions of the Universe at the highest granularity possible were known (10^1000? likely higher), then to calculate the current state of the Universe (10^17 seconds) at every step along the way, once per Planck time (10^44 per second), ... a calculation on the order of 10^1000^10^17^44 states (did I get that right?) No computer which exists IN our universe could hope to tackle such a calculation ABOUT said universe, in any reasonable amount of time. (Of course you could cheat like game developers do, but that's another conversation.) Second, if a conscious entity is able to calculate and predict step N+1, they can choose to alter that step. This kind of article and comment is fun to think about -- does it even make sense to ask the question in the first place?
- rmbyrro 5y ago
  Interesting angle. One question arises for me: if no computer IN the universe can calculate this, how are these rules being applied? I mean, something must be enforcing, there's no "magic" voodoo in the Universe, that's for sure. So how can these rules keep being enforced, so that the outcomes follow the "predicted" path, if the universe can't possibly be able to "calculate" everything?

ccvannorman 5y ago

Exactly this! First, if all the initial conditions of the Universe at the highest granularity possible were known (10^1000? likely higher), then to calculate the current state of the Universe (10^17 seconds) at every step along the way, once per Planck time (10^44 per second), ... a calculation on the order of 10^1000^10^17^44 states (did I get that right?) No computer which exists IN our universe could hope to tackle such a calculation ABOUT said universe, in any reasonable amount of time. (Of course you could cheat like game developers do, but that's another conversation.) Second, if a conscious entity is able to calculate and predict step N+1, they can choose to alter that step. This kind of article and comment is fun to think about -- does it even make sense to ask the question in the first place?

rmbyrro 5y ago
Interesting angle. One question arises for me: if no computer IN the universe can calculate this, how are these rules being applied? I mean, something must be enforcing, there's no "magic" voodoo in the Universe, that's for sure. So how can these rules keep being enforced, so that the outcomes follow the "predicted" path, if the universe can't possibly be able to "calculate" everything?