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)

  • 1
    Nice try, but it is not possible to solve philosophical questions by running scientific experiments. .
    – user20253
    Commented Nov 15, 2018 at 13:01
  • 3
    @user20253 Apart from all the times we did that, of course. ("Atoms and the void", anyone?)
    – wizzwizz4
    Commented Sep 10, 2022 at 22:54
  • 2
    I'm reasonably confident that it is literally impossible to know a particle's speed and location, so, no. Also, the way you would verify perfect knowledge would be by successful prediction, so if you failed in your prediction you couldn't eliminate the possibility that your model was flawed.
    – philosodad
    Commented Nov 4, 2022 at 13:53
  • 1
    Basically, we have done that experiment, and established that our universe is not predictable. This is most obvious in quantum mechanics, where the "state of the universe" cannot be established other than probabilistically. But classical physics is also probabalistic. And chaos phenomena leverage probability into macro scale indeterminacy. See this answer: philosophy.stackexchange.com/questions/87093/…
    – Dcleve
    Commented Nov 4, 2022 at 16:46
  • Where would you store your snapshot of the universe? How many atoms do we need to register the state of an atom? Also, making a few perfect predictions wouldn't really rule out randomness, miracles or free will. Only that nothing unexpected happened so far. It could still happen later.
    – armand
    Commented Nov 7, 2022 at 3:30

4 Answers 4


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
    Commented Nov 15, 2018 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
    Commented Nov 15, 2018 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
    Commented Nov 15, 2018 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
    Commented Nov 15, 2018 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
    Commented Nov 17, 2018 at 11:09

The existence of free will and randomness cannot be tested by any experiment. Neither concept is a theory that could be verified or refuted.

Both concepts are matters of definition. Define them properly and you will know whether they describe a real or an imaginary phenomenon.

  • Free will as the ability to do according to your preferences - Yes, we do have that ability.

  • Free will as the ability to choose your preferences - No, we don't have that ability.

  • Randomness as unpredictability - Yes, there are unpredictable events.

  • Randomness as unintentionality - Yes, things do happen without anyone's intention.

  • Randomness as inaccuracy - Yes, there is no absolute accuracy anywhere in reality.

  • Randomness as non-causality - No, there are no uncaused events.


True randomness is removed from our universe to create our biosphere (and the Kalabi-Yau membrane). It exists, however, outside of it.

The experiment assumes a notion of ordered dimensionality, otherwise you can't get your so-called perfect data. In other words, the experiment assumes order and determinism, creating a logical problem.


i think this the classic debate of the deterministic universe.

in my opinion in a system with no external interferences if we start from the SAME position we reach the same next position and so on ad eternum.

other thing is that exists a barrier that we cannot be traspassing....we cannot know all the elements and parameters of ALL, so its imposible to predict.

So maybe the question changes to the illusion of random is the same as random?

  • It is not possible to have the SAME position again. You cannot rewind time. Commented Nov 4, 2022 at 12:24
  • I know almost nothing about physics....but one can imagine that if all the matter of the universe is condesed again in a single point and "explotes" again in a infinite loop of contractions-explosions the time starts again from "ZERO" so the existence is reapeting infinite times in the SAME way forever
    – oso_togari
    Commented Nov 4, 2022 at 12:58
  • This seems to be about your personal opinion and not based on (expert) knowledge on the subject matter. Please read the articles in our help center to get a grip on how the site works. We tend to love references and good arguments here on StackExchange, opinions not that much.
    – Philip Klöcking
    Commented Nov 4, 2022 at 18:10
  • its funny that you mention "expert" in a field like philosphy and physics full of opinions, facts without demostrations and theories continuosly refuted......but yes, you are right is my opinion......anyway, not very dificult to say the same for more comments here...hehe
    – oso_togari
    Commented Nov 6, 2022 at 10:33

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