Consciousness and Computation

The hardest problem for the hypothesis is consciousness. Even if we could simulate every physical process in a brain, would the simulation be conscious or merely behave as if it were? This is the philosophical zombie problem applied to computation.

If consciousness needs a specific physical substrate — biological neurons, or something we have not discovered — then simulated brains might be perfect behavioral copies without inner experience. They would look right from the outside, but nobody would be home inside.