If (1) we assume the universe has a finite size, and (2) we took a snapshot of the universe that includes particle speeds and locations, and (3) using perfect knowledge of science, would this be the perfect test of the existence of true randomness?

If true randomness existed, then using the data to simulate the future would fail tremendously because randomness can't be simulated.

If randomness did not exist, we could at least remove the possibility of one of the two free will concepts. We would also would disprove the existence of any divine entities.

Would this theoretically be the one experiment to solve every philosophical question? (Also for extra credit use Moore's law to make a formula to convert size of the universe to years we would need to wait to get a computer to have enough processing power. gl)

  • Nice try, but it is not possible to solve philosophical questions by running scientific experiments. .
    – user20253
    Nov 15 '18 at 13:01

Firstly, we don't need randomness in order to be unable to predict future events. The universe only need one chaotic process to compromise certainty. A better test would be to take two snapshots and see if: everything in the first snapshot predicts the state of the second, and if everything in the second follows from the state of the first.

If a discrepancy is found we know our "perfect test" is based on incomplete knowledge, or some divinity is messing with us. If there is no discrepancy we have a Black swan, meaning that we could never have absolute certainty that our perfect predictions will not suddenly start to fail.

Another problem is that the more certain we are about our predictions the less certain we are that we are not actually living in a simulated reality. Again in this case everything could change without warning. This possibility alone could account for free will, miracles, precognition...

I'm sure by now you can see all kinds of "holes" opening where a divinity could hide. That is because the concept is defined to be beyond logic, which makes reasoning about God very tricky.

Also you may be interested in this, which is kind where you are going with this line of reasoning. Think for a second, if you run a computer simulation of the entire universe, then that computer, and its simulation, would also have to be run inside the simulation...

  • With the simulation inside a simulation, all of those particles are just more particles, so it should be fine. Otherwise, I completely agree with your answer. Thanks!
    – gsquaredxc
    Nov 15 '18 at 13:30
  • A simulation is not particles, it is a process built from particles. The problem is that the (physical) computer's simulation would also have to include itself in its simulation which would also have to include itself in its simulation...
    – christo183
    Nov 15 '18 at 13:40
  • Well the theory is that the particles would still have set velocities and positions, so it would be predetermined assuming no randomness.
    – gsquaredxc
    Nov 15 '18 at 15:58
  • Good point on chaos -- but it is not clear whether chaos is an actual state of the universe, or if it is an approximation that could be removed with more complete information.
    – Dcleve
    Nov 15 '18 at 19:00
  • @Dcleve "Chaos" used here in the technical sense. I.e. "more complete information" can, and do, yield more accurate results. However, predictive uncertainty rises exponentially over time. In other words it is cheaper to approximate.
    – christo183
    Nov 17 '18 at 11:09

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