God Soul Mind Brain

that when he spoke to these patients and they spoke back, he was talking only to the left hemisphere. It was the only hemisphere that could talk back. When he spoke to the patients after their surgery, the left hemisphere didn’t seem to notice anything unusual. It knew that it had undergone an operation, but it didn’t feel any differently afterward. It didn’t report that it missed the right side in any manner.

    The right hemisphere still functioned. It still computed, decided, and acted. It was mainly responsible for controlling the left side of the body. The two sides of the body had to function like dance partners making expert and practiced moves together without any direct thought-connection. Why didn’t the left hemisphere notice that it had been split off from direct contact with its other half, that it was now sitting side by side with a separate intelligence making independent decisions? The left hemisphere’s delusion that it was in conscious control of the entire body was the most bizarre symptom of the surgery.

    To trace down the reason, Sperry and his colleagues did experiments to put the two hemispheres at odds with each other. For example, suppose a picture of a shoe is flashed on the left side of a projection screen. The patient, looking at the screen, would see this picture with the right (non-speaking) hemisphere of the brain. At the same time, a picture of a kite is flashed on the right side of the screen. The kite would be seen by the patient’s left (speaking) hemisphere.

    If you ask the person, “What did you see?” his left, speaking hemisphere might answer: “A kite.”

    If you tell the person, “Point with your left hand and show me what you saw,” now the person might point to the shoe on his foot. Why? Because although the non-speaking hemisphere cannot verbalize its answer, it can understand language well enough to follow simple instructions, and it controls the left hand.

    Now you ask the person, “Why did you point to your shoe?” The speaking hemisphere might say, “I was pointing to the shoelace, which is a little like the string on a kite.”

    The answer is confident. The left hemisphere asserts it as if it were a simple truth and not a wild fabrication invented after the fact. The experimenter and the right hemisphere of the patient both know the real reason, but the left hemisphere has made up its own reason and is content with it. The reason why the left hemisphere thinks it is in control of the entire body is evidently because, whatever action the body performs, the left hemisphere makes up a plausible reason to account for the action. It thinks it chose to perform that action. One presumes the right hemisphere is doing the same thing on its side, confabulating explanations for the body’s actions, but because the right hemisphere doesn’t speak, it can’t easily explain its thoughts to the experimenter.

    Experiments of this type reveal the incredible extent of confabulation. Our comfortable, stream-of-consciousness explanation of our actions is not particularly accurate. It is partly an invention. The machinery for social perception is wired to confabulate about other people, to take in someone else’s behavior and construct and update a useful if simplified model about that person’s intentions. That machinery is simply doing to ourselves what it normally does to others.

    When we say we are conscious, aware, self-aware, in conscious control of our actions, have a stream-of-consciousness understanding of ourselves, what we really mean, apparently, is this: there is a system in the brain whose job is to construct models of intentionality of other people or of ourselves; and right or wrong, confabulated or not, the self-model, continuously updated, continuously refined, supplies the contents of our conscious minds.

    In this sense consciousness—a soul on a trajectory through waking life—is a perceptual illusion. It is a perceptual model that is at best a simplification and sometimes plain wrong.

Consciousness as decision-making

    No matter how you study consciousness, whether you are casually introspecting, spinning philosophies, or trying to study it in a laboratory, inevitably the process comes down to asking a general, underlying type of question: is person X aware of thing Y? Whether you are introspecting (“Am I aware of the coolness of the breeze? Was I aware of it a moment before I focused my attention on it? Am I aware of myself at this