In The Man Who Mistook his Wife for a Hat (Summit Books, 1985), Oliver Sacks makes clear how flimsy our hold on reality, on our sense of reality, really is. Most of us accept the necessity of living with the risk of events that will injure or kill us—automobile accidents, fires, assaults, sudden illness. I don’t think we are nearly as conscious of the possibility that physical events—stroke, brain infection—will sever or significantly alter our ability to live in and understand the world.
Most of the case studies in this book are of people who were born with brain deficits, or who at an early age suffered a disease such as encephalitis that left their brains damaged. One man cannot remember events after 1945—he has no short-term memory; a pair of twins are mathematical savants who can calculate 10 digit prime numbers in their heads even though they have IQs of 60; a severely damaged man can draw images with skill; a woman dying from brain cancer is overwhelmed with visions of serenity as the disease slowly eats away at her personality; a woman loses her ability to understand the concept of “left”—she cannot process what she sees with her left eye, she cannot use her left hand, she cannot even turn to the left—the left doesn’t exist for her; another women loses her sense of connection to her own body—to move her limbs, she has to look at and think about moving them—her body becomes in essence a machine that she can control but to which she feels no connection. The list of afflictions goes on.
Sacks’ book makes clear that our connection to reality, our sense of it, and even, in effect, reality itself, is a physiological function, a brain function. I thought of the James Dickey poem "Pursuit from Under" in which the poet imagines himself walking on the arctic ice, looking down to see the killer whale that is stalking him beneath the ice. This is a metaphor for the constant presence of the possibility of death, of non-existence. In Sack’s book it is the brain whose malfunction can dissolve reality, our world, our identity, entirely.
Sacks writes in a style that is somewhat aimed towards the layperson but that is also clearly the prose style of a doctor. He makes frequent reference to other neurologists and to studies of the brain and employs terms that are specific to the discipline of neurology. Oddly, he uses terms such as retardate, moron, simpleton, dullard. I suppose in the field of neurology they have specific meaning while in common parlance they are unacceptable
Sacks writes with great compassion for his patients even while he regards them in the most clinical and detached way. In each of his patients, he looks for humanity, and he seems to feel that the health industry and society’s tendency to institutionalize people with extreme brain deficits, or to assume they are incapable of living a normal life, overlooks what they are capable of in many cases—personal fulfillment and satisfaction, even of use to the human community.