Philosophy

In the general case, I think that we would not be able to tell. Unless the programmers explicitly program into the simulation the tools for us to interact with the external world, we would not be able to collect evidence of something external to the simulation. We are limited.

I am agnostic to whether we live in a simulation or not, but I don't think that this hypothesis brings a lot in terms of answering existential questions. We could live in a simulation inside of a simulation inside of a simulation inside of a simulation..... meaning that there is an infinite depth of simulations when we choose to consider this possibility. In my view, being the first rung of existence or being a million simulations deep is the same. Discovering that we are in a simulation just shifts the existential question one universe higher.

I have been reading some texts about theories of how the brain thinks (predictive coding), and it seems like what we experience as "consciousness" might be the result of our brain simulating what our next sensory experience will be. So, in that sense, we are all experiencing our brain's predictive simulation.