Aristotle’s definition of man as a rational animal has recently taken quite a beating.
Part of the attack comes from neuroscience. Pretty, multicolored fMRI maps make clear that our mental lives can be observed in the activity of our neurons, and we’ve made considerable progress in reading someone’s thoughts by looking at those maps. It’s clear, too, that damage to the brain can impair the most-intimate aspects of ourselves, such as the capacity to make moral judgments or to inhibit bad actions. To some scholars, the neural basis of mental life suggests that rational deliberation and free choice are illusions. Because our thoughts and actions are the products of our brains, and because what our brains do is determined by the physical state of the world and the laws of physics—perhaps with a dash of quantum randomness in the mix—there seems to be no room for choice. As the author and neuroscientist Sam Harris has put it, we are “biochemical puppets.”
This conception of what it is to be a person fits poorly with our sense of how we live our everyday lives. It certainly feels as though we make choices, as though we’re responsible for our actions. The idea that we’re entirely physical beings also clashes with the age-old idea that body and mind are distinct. Even young children believe themselves and others to be not just physical bodies, subject to physical laws, but also separate conscious entities, unfettered from the material world. Most religious thought has been based on this kind of dualist worldview, as showcased by John Updike in Rabbit at Rest, when Rabbit talks to his friend Charlie about Charlie’s recent surgery:
“Pig valves.” Rabbit tries to hide his revulsion. “Was it terrible? They split your chest open and ran your blood through a machine?”
“Piece of cake. You’re knocked out cold. What’s wrong with running your blood through a machine? What else you think you are, champ?”
A God-made one-of-a-kind with an immortal soul breathed in. A vehicle of grace. A battlefield of good and evil. An apprentice angel …
“You’re just a soft machine,” Charlie maintains.
I bristle at that just, but the evidence is overwhelming that Charlie is right. We are soft machines—amazing machines, but machines nonetheless. Scientists have reached no consensus as to precisely how physical events give rise to conscious experience, but few doubt any longer that our minds and our brains are one and the same.