I wonder whether a human calculating a math problems is not unlike a computer simulating another computer. Observing the hand-eye coordination of top athletes, it's pretty clear that our brains do some amazing computations, and fast. In fractions of a second, we can turn a pattern of photons into concepts, discover relationships between those concepts, track changes over time, and project all of that out some distance into the future. In other words, aren't most of our computational capabilities buried in the unconscious mind?