Indeed. We humans largely create devices that function either through calculation or through physical reaction, relying on the underlying rules of the universe to "do the math" of, say, launching a cannonball and having it follow a consistent arc. The brain combines both at almost every level. It may be fundamentally impossible to emulate a human personality equal to a real one without a physics simulation of a human brain and its chemistry.

A dragonfly brain takes the input from thirty thousand visual receptor cells and uses it to track prey movement using only sixteen neurons. Could we do the same using an equal volume of transistors?