God Soul Mind Brain

assigned to it, and the model is as simplified, and as subject to error, as any other perceptual model.

    We talk about the inner me, the inner self, our private experience, and we contrast that with the world that we perceive outside of us. We think of these worlds as being fundamentally different in nature. Wasn’t that Descartes’ point when he famously said, “I think, therefore I am”? He didn’t trust his perceptions of the outside world, but he thought he could trust his access to his own mind. What I am suggesting is that this distinction is an artificial one. Inner self or outer world, it is all perception. The difference lies mainly in the spatial coordinates assigned to the perceptual model. In some cases, attributes are assigned to locations inside our bodies. In other cases, attributes are painted onto people or animals or objects in the world around us.

    The central philosophical question of consciousness is often put this way: Why does thinking feel like anything at all? When I solve a math problem in my head, why don’t I merely process the information without feeling it? Why does it come with the added property that it feels like something to me? First consider the interesting format of the question—the analogy between thinking and body sensation. Why feel ? The similarity, I am suggesting, is that in both cases your perceptual machinery creates a model as a proxy for the real thing, in both cases the model has a location assigned to it, and in both cases that location is referenced to the body. You perceive your own thoughts to be inside your own head, just as (to be prosaic about it) you perceive a stomach ache to be inside your own gut. In both cases the perceptual model is assigned a location inside the personal boundaries of the body. Hence the natural tendency to label the perception of one’s own thinking as a type of feeling . Both belong to the category of perceiving the internal environment.

Confabulation

    If you are thoughtful or observant, you probably long ago noticed that some of your behavior is shaped by unknown processes outside your awareness. Maybe you accidentally poured orange juice in your coffee—picked up the carton and did it without even noticing until it was too late. Or maybe someone asked you an innocent question and you found yourself snarling back, surprised at your own anger and unsure where the emotion came from. If you are human at all, then some time in the past you acted in a way that you couldn’t entirely explain. But these rare moments are only the tip of the iceberg. They are the obvious cases in which your behavior was so nonsensical, so surprising to you, that you couldn’t invent an easy explanation, and so you were forced to recognize that something unconscious in your brain caused it to happen. But less obvious cases occur constantly. You may act in a way that seems quite natural—you think your conscious mind has decided to act this or that way, and you think you know the reason—but the real reason might not be consciously known to you.

    Psychologists call it confabulation, and there are many experimental examples of it. The most telling examples come from the famous split-brain experiments of the 1960s. Although conducted nearly fifty years ago, these experiments are just as remarkable and revealing today as they were then. In those experiments, one half of a person’s cerebral cortex was surgically disconnected from the other half. The reason was to prevent the spread of epilepsy from one side of the brain to the other. Medically, the experiments were an astonishing success. People who used to have frequent Grand Mal seizures would instead suffer only occasional, brief, Petite Mal seizures. They were almost cured. As a side benefit, the surgery allowed scientists to study the two halves of the brain separately. (These days epilepsy is better controlled by drugs.)

    The split-brain experiments are especially interesting because of a peculiar feature of the human brain. In most people, the left side of the brain is capable of speaking fluently, whereas the right side has very little if any speech ability. This asymmetry between the two hemispheres varies somewhat from person to person, but the pattern holds for most people. It is one of the more remarkable properties of the human brain, though the value of it, if there is any, is still debated.

    The neuroscientist Roger Sperry, who pioneered the study of split-brain people, realized