The Objections

Critics raise serious counterarguments. Simulating consciousness may require fundamentally more computing power than simulating physics — possibly more than any physically realizable computer could provide. We do not even understand what consciousness is, let alone how to simulate it.

There is also the regression problem. If we are in a simulation, our simulators might also be in a simulation, and so on infinitely. The base reality at the bottom of this stack would have to be fundamentally different from every simulation stacked above it.