More than 2,000 years ago, the semi-mythical father of medicine, Hippocrates of Kos, challenged the spiritualists of his time with a bold claim about the nature of the human mind. In response to supernatural explanations of mental phenomena, Hippocrates insisted that ‘from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations’. In the modern age, Hippocrates’ words have been distilled into a Twitter-friendly pop-neuroscience slogan: ‘We are our brains.’ This message resonates with recent trends to blame criminality on the brain, to redefine mental illness as brain disease and, in futuristic-technological circles, to imagine enhancing or preserving our lives by enhancing or preserving our brains. From creativity to drug addiction, there is barely an aspect of human behaviour that has not been attributed to brain function. To many people today, the brain seems like a contemporary surrogate for the soul.
But lost in the public’s romance with the brain is the most fundamental lesson neuroscience has to teach us: that the organ of our minds is a purely physical entity, conceptually and causally embedded in the natural world. Although the brain is required for almost everything we do, it never works alone.