The Brain: The Story of You

by David Eagleman

In 1714, Gottfried Wilhelm Leibniz argued that matter alone could never produce a mind. Leibniz was a German philosopher, mathematician, and scientist who is sometimes called “the last man who knew everything”. To Leibniz, brain tissue alone could not have an interior life. He suggested a thought experiment, known today as Leibniz’s Mill. Imagine a large mill. If you were to walk around inside of it, you would see its cogs and struts and levers all moving, but it would be preposterous to suggest that the mill is thinking or feeling or perceiving. How could a mill fall in love or enjoy a sunset? A mill is just made of pieces and parts. And so it is with the brain, Leibniz asserted. If you could expand the brain to the size of a mill and stroll around inside it, you would only see pieces and parts. Nothing would obviously correspond to perception. Everything would simply be acting on everything else. If you wrote down every interaction, it wouldn’t be obvious where thinking and feeling and perceiving reside.