Who had determined from an early age to disprove the existence of God and the Soul, made a passionate call for neuroscience to begin employing its grow- ing scientific arsenal to demonstrate the material basis of consciousness?

Philosophers have been arguing about over the past few centuries. Ever since René Descartes gave birth to dualism by asserting the separation of Mind and Body, the big issue in the philosophy of mind has been figuring out how these two different substances—the mental and the physical—could interact with one another. On one hand, how could an objective, physical brain give rise to subjective, mental events? And on the other hand, how could those subjective, mental events—presumably not governed by physical laws—impact the objec- tive, physical world?

Through the use of brain imaging techniques, it allows them to compare snap- shots of the brain when a given perception is conscious and when it is not con- scious. This, they hope, will ultimately give them some clues to understanding how neuronal activity correlates with consciousness. No matter how clear a snapshot we can get of what type of neuronal activity correlates with which sorts of conscious perceptions, we will still be no closer to understanding how the brain could possibly produce something like conscious experience itself.

Whereas we now see a vast, complex electrochemical network of some hun- dred billion neurons, these early anatomists were convinced that the Mind, or Soul, was a kind of etheric presence that lived in large “ventricles” or chambers in the brain, communicating its commands to the rest of the body through “vital spirits” that flowed through the nervous system’s minute pathways.

Indeed, it has been this move away from a spirit-based view of the brain’s work- ings toward a purely biological one that has led to the idea, so unpopular with the religiously inclined, that the mind, or soul, is ultimately reducible to brain activity.