Okay, so this is something that has fascinated me for a long time. Simulation theory is this wild notion that we are currently living in a simulation. And to boot, is some really compelling evidence to this wild notion.
Piece of evidence #1: Processing power is getting better and better as the years carry on, and with it, our ability to create better and better simulations. If you have played a video game in the last 10 years, you are aware of this. Eventually, the processing power will reach a point where humans will be able to simulate at least a small part of an entire universe. This could be use for research of earlier cultures, or initial conditions to study possible outcomes. It starts raising a lot of questions indeed about what sort of moral code of conduct there is, if any, regarding shutting off a simulation which may or may not contain lives.
Piece of evidence #2: If a simulation is indeed being run, there would be some limit to the computing power involved in the simulation, and thus there would be some sort of upper limit on the size of the universe in question. Sound familiar?
Piece of evidence #3: If a simulation is indeed being run, there would be some limit to the computing power involved in the simulation, and thus there would be some resolution limit on the size of all the pieces which made the universe in question. Sound familiar? If not, let me direct your attention to the Heisenberg Uncertainty Principle, and also this excellent comic: here.
Piece of evidence #4: There would be an incompatibility of the behavior of large scale and small scale objects. This would probably be due to the fact that things would need to behave a certain way in the large scale, and the inner mechanics of how those things worked on the small scale wouldn't be all that important, unless small creatures inside the simulation started to examine what was going on at a small scale and developing theories for why that might be. You could also characterize this as the current incompatibility of classical and quantum mechanics. As of right now the do not jibe.
Anyone considering the ledge of the nearest window at this point, read on, stay your hand. There may be some good news after all. Unfortunately that news is string theory. String theory in its current state is our hope to unite classical and quantum mechanics, and gives us some glimmer of hope that we are indeed dealing with a universe that at least pretends to have continuous laws.
Wouldn't that simplify so many questions in life, though? It would explain why there are physical laws, why you need to go to sleep all the time, why reality gets "fuzzy" sometimes, why the uncertainty principle exists, why there's an edge to the universe, and on and on. Plenty of unsubstantiatable questions and answers. Cold comfort indeed.
