We can distinguish between two kinds of mind function: awareness (the dispassionate observer) and the jumble of automatic processes (conscious, semiconscious and subconscious) that dictate our emotional states, thoughts and much of our behaviour. One of the first scientists to recognize this distinction was the great Canadian neurosurgeon Wilder Penfield. “Although the content of consciousness depends in large measure on neuronal activity, awareness itself does not,” Penfield wrote. “To me it seems more and more reasonable to suggest that the mind may be a distinct and different essence from the brain.”