“Do I believe, for example, that by using magic I could fly? No. How would you get around gravity? Impossible. Do I believe that I might be able to project my consciousness into a very, very vivid simulation of flying? Yeah. Yes, I’ve done that. Yes, that works.” -Alan Moore
If you possessed a computer with enough power, you could conceivably simulate the entire Universe. From the inception of the Big Bang, you could compute the positions and momenta of every particle and every interaction over time, across all 13.8 billion years. If your simulation was good enough, you could even account for quantum processes and uncertainty, and you’d wind up with planets, life, and even human brains at the end.
But if this were representative of our reality, would there be any way to tell? Maybe computational short-cuts would show up as some sort of fundamental blurriness at small enough scale. And what would that tell us about our quest to understand the fundamental constants, particles and interactions that define our Universe? Would it all be futile? Perhaps there would still be something important to learn about our existence by asking the right fundamental questions through experiments.