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.
Another attack on rationality comes from social psychology. Hundreds of studies now show that factors we’re unaware of influence how we think and act. College students who fill out a questionnaire about their political opinions when standing next to a dispenser of hand sanitizer become, at least for a moment, more politically conservative than those standing next to an empty wall. Shoppers walking past a bakery are more likely than other shoppers to make change for a stranger. Subjects favor job applicants whose résumés are presented to them on heavy clipboards. Supposedly egalitarian white people who are under time pressure are more likely to misidentify a tool as a gun after being shown a photo of a black male face.
In a contemporary, and often unacknowledged, rebooting of Freud, many psychologists have concluded from such findings that unconscious associations and attitudes hold powerful sway over our lives—and that conscious choice is largely superfluous. “It is not clear,” the Baylor College neuroscientist David Eagleman writes, “how much the conscious you—as opposed to the genetic and neural you—gets to do any deciding at all.” The New York University psychologist Jonathan Haidt suggests we should reject the notion that we are in control of our decisions and instead think of the conscious self as a lawyer who, when called upon to defend the actions of a client, mainly provides after-the-fact justifications for decisions that have already been made.
Such statements have produced a powerful backlash. What they represent, many people feel, are efforts at a hostile takeover of the soul: an assault on religious belief, on traditional morality, and on common sense. Derisory terms like neurotrash, brain porn, and (for the British) neurobollocks are often thrown around. Some people, such as the novelist Marilynne Robinson and the writer and critic Leon Wieseltier, argue that science has inappropriately ventured outside its scope and has still failed to capture the rich and transcendent nature of human experience. The author and clinical neuroscientist Raymond Tallis worries that such theories suggest no meaningful gap separates man and beast, a position that he argues, in Aping Mankind, is “not merely intellectually derelict but dangerous.”
For the most part, I’m on the side of the neuroscientists and social psychologists—no surprise, given that I’m a psychologist myself. Work in fields such as computational cognitive science, behavioral genetics, and social neuroscience has yielded great insights about human nature. I do worry, though, that many of my colleagues have radically overstated the implications of their findings. The genetic you and the neural you aren’t alternatives to the conscious you. They are its foundations.
Knowing that we are physical beings doesn’t tell us much. The interesting question is what sort of physical beings we are.
Nobody can deny that we are sometimes biochemical puppets. In 2000, an otherwise normal Virginia man started to collect child pornography and make sexual advances toward his prepubescent stepdaughter. He was sentenced to spend time in a rehabilitation center, only to be expelled for making lewd advances toward staff members and patients. The next step was prison, but the night before he was to be incarcerated, severe headaches sent him to the hospital, where doctors discovered a large tumor on his brain. After they removed it, his sexual obsessions disappeared. Months later, his interest in child pornography returned, and a scan showed that the tumor had come back. Once again it was removed, and once again his obsessions disappeared.
Other examples of biochemical puppetry abound. A pill used to treat Parkinson’s disease can lead to pathological gambling; date-rape drugs can induce a robot-like compliance; sleeping pills can lead to sleep-binging and sleep-driving. These cases—some of which are discussed in detail by David Eagleman in Incognito: The Secret Lives of the Brain (excerpted in the July/August 2011 Atlantic)—intrigue and trouble us because they involve significant actions that are disengaged from the normal mechanisms of conscious deliberation. When the victims are brought back to normal—the drug wears off; the tumor is removed—they feel sincerely that their desires and actions under the influence were alien to them, and fell outside the scope of their will.
For Eagleman, these examples highlight the need for a legal framework and criminal-justice system that can take into account our growing understanding of brain science. What we need, he argues, is “a shift from blame to biology.” This is reasonable enough. It’s hardly neurobollocks to think we should take the existence of a tumor into account when determining criminal responsibility for a sex offense.
But some cases raise thorny questions. Philosophers—and judges and juries—might disagree, for instance, as to whether an adult’s having been horrifically abused as a child can be considered as exculpatory as having a tumor. If the abuse visibly changed a person’s brain and stripped it of its full capacity for deliberation, should that count as a mitigating condition in court? What about individuals, such as certain psychopaths, who appear incapable of empathy and compassion? Should that diminish their responsibility for cruel actions?
Other cases are easier. It’s not hard to see the psychological distinction between the cold-blooded planning of a Mafia hit man and the bizarre actions of a paranoid schizophrenic. As you read this article, your actions are determined by physical law, but unless you have been drugged, or have a gun to your head, or are acting under the influence of a behavior-changing brain tumor, reading it is what you have chosen to do. You have reasons for that choice, and you can decide to stop reading if you want. If you should be doing something else right now—picking up a child at school, say, or standing watch at a security post—your decision to continue reading is something you are morally responsible for.