The Impossible Test For Universal Indeterminism
Morning musings on models vs. metaphysics...
No one has ever established whether the universe is fundamentally deterministic or probabilistic. This is one of those strange, counterintuitive facts that change the way you view reality (not just physics) once you comprehend it. It’s similar to how it’s counterintuitive that your feeling of “weight” is actually never due to pure gravity; instead, it’s due to electromagnetism.
Why? While the equations of classical mechanics are deterministic (meaning that given initial conditions, the future evolves uniquely), this determinism isn’t directly testable as an empirical proposition about reality itself.
You can’t conclusively rule out hidden non-deterministic factors in actual physical systems through experiment alone.
Any observed agreement with deterministic equations may also be explained by suitable probabilistic theories that mimic determinism within experimental error.
Hence, the claim is that “determinism” in classical mechanics is a metaphysical add-on, and NOT a directly falsifiable statement.
Strictly speaking, you can test whether classical mechanics’ predictions match observations, but testing whether “the universe truly is deterministic” goes beyond just verifying the equations’ predictive success.
Similarly, for so-called random systems, any observed randomness could still be deterministic in some hidden manner. If measurements match a probabilistic model, that doesn’t exclude an undiscovered deterministic theory that mimics those probabilities.
Stating whether something is deterministic or probabilistic is mostly an unfalsifiable statement at this point.
You disconfirm models. Not metaphysics.
I want to hear from you in the Substack comment section below. I read each and every response.
- Curt Jaimungal
Since, I am a firm believer in free will, I would say, I have a probability of certain choices to make based on a spectrum of rationality ranging from less to more rational. Each of our choices affects the universe. The needs of every conscious entity drive the decisions of the universe but if we change or make less rational decisions, the universe has to course correct which isn't easy. So I guess the universe is both probabilistic and deterministic if you follow this train of thought. But again, how could you test this??!??! Thanks for doing what you do Mr. Jaimungal.
How do we have a world where cause and effect are real, but also there is probability?
By the existence of something outside our cosmos, that can affect our cosmos but itself is not caused by our cosmos.
If you were a consciousness in a video game, and could study your “universe” (the inner workings of the computer), you would find complete cause and effect.
Everything that exists in your video game universe is 100% explained by movements of electron voltage potentials through computer chips and memory and so on.
And yet…there are inputs from “outside” your universe. That is, inputs from the user’s keyboard and mouse.
Those inputs are not caused by processor or memory chip—the cause is completely outside of the computer universe.
But once those inputs enter into the computer’s universe, they follow the rules of physics within the computer.
I think our universe works similarly. With inputs from consciousnesses outside of the cosmos.