Oliver Sacks: The Minds Eye

I just finished reading Oliver Sacks’ latest book, the Mind’s Eye. I highly recommend it. Sacks is a person of generosity and curiosity who does not see people as cases or disabilities but as somebody worth getting to know.

This book deals with vision. (The cover reproduces a “migraine aura” or the scintillating crystallization of the visual field during a migraine headache so well, in my experience, that it deserves a book cover award.) The central essay is based on journal entries he kept between December 2005 and 2009 when he first noticed something funny going on with his right eye. Sitting in the cinema he notices strange lights flaring up, as well as blindspots. Panicking, he rushes out the cinema.

Following tests it’s revealed that he has a melanoma in his eye. It might or might not metastasize. Over the next several months and years he undergoes a series of operations including radiation and lasering. Throughout this process he keeps a close record of his experiences, especially the distortions and mis-perceptions in his visual field. Unfortunately the melanoma is very near the central fovea and soon he starts to lose stereo vision–and this for a member of the New York Stereoscopy Society!

Sacks is eloquent on living in a 2D world. Thinking about my own experiences there have been occasions when I can’t tell where say a spider’s thread glinting in the sun is in space. My eyes try focusing on it fruitlessly. Is it by my nose or 20 feet away? It’s disorienting (literally) and a little disturbing. For Sacks, eventually this becomes a common reality:

My inability to see depth or distance leads me to combine or conflate near and far objects into strange hybrids or chimeras. One day I was puzzled to find a gray web between my fingers, before I realized that I was seeing the gray carpet three feet below–now seen on the same plane as my hands and construed as part of them. I was horrified one day, looking at a friend in profile, to notice twigs or slivers of wood coming out of her eyes–but these belonged, I soon, realized, to a tree across the road…nothing protrudes or recedes from me anymore; there is no direct sensation of “before” or “behind,” only an inference based on occlusion and perspective. Space was once a hospitable, deep realm in which I could locate myself and wander at will…I had a spatial relationship to everything I could see. That sort of space no longer exists for me.

(In a twist, he also loses all fear of heights that he once had, and can look “down” nonchalantly from high balconies that he once avoided.)

Over time he loses sight in his eye altogether and with it a strange new experiential condition: he is not aware of his right side (or even aware that something is amiss). Standing at the elevator with his friend, he waits patiently for her to catch up with him, only to hear her say “what are you waiting for?” She was standing to his right while he thought she had gone off somewhere. “Out of sight, out of mind” becomes literal for him. His brain is filling in the scene (even though he’s lost about 40% of his visual field). He must constantly remind himself to turn his neck and body to peer into the “missing” area. Walking along his Greenwich Village neighborhood, he hugs the right side of the sidewalk as much as possible to avoid bumping into people or tripping on children.

One of the threads that runs through Sacks’ work is his emphasis on the experiential in collusion with both knowledge and aspects of neurology (perception, biology, the brain etc.) It’s not surprising to see him use the phrase, as he does in this book, of being-in-the-world. (Richard Polt’s 1999 book on Heidegger uses a story from The Man who Mistook his Wife for a Hat to illustrate a point.)

Sacks notes that patients who have had parts of their body anesthetized no longer receive signals in their brains to represent these body parts. They can look at their legs and not realize that they are their own. (A parallel to this is when you’ve slept on your own arm and it goes to sleep. If you touch it to move it, it’s like a dead thing, almost repellent. It’s certainly not your own.)

This loss of vision for Sacks is a debilitating condition for him; his world is 40% “nowhere.” Yet Sacks ends his book with another essay on people who are blind from birth or who go blind. He finds that in some cases (not all) these people have rich representational worlds. Sometimes other senses enlarge to compensate. One writer speaks of sensing cars and lampposts as “thickenings” of the air even when they’re making no sound, allowing him to avoid them and know that they’re there. Another young man used echolocation by emitting a series of clicks and reading the echoes from nearby objects. (I was reminded here of the novels of Peter O’Donnell who wrote the Modesty Blaise thrillers; one of the characters, blind since childhood does this. I always though this was a fanciful invention of the author until now.)

This raises the question of whether our thoughts are visual or not. Blind people who report imagery, or even authors writing and evoking landscapes from places they’ve never visited, would seem to indicate that it is. Sacks refers to the work of Stephen Kosslyn on mental imagery (which I first read in grad school in the 1980s). Or what about Roger Shepard’s famous rotation experiments where people mentally rotate an image? Here, the further you have to mentally rotate the image, the longer it takes you to do it. Kosslyn even suggests that we need mental imagery in order to perceive things. If we don’t sort of know what we might be looking at, we can’t perceive it properly (size for example).

This is shown by another condition Sacks has, the inability to recognize faces, even of close colleagues and friends, if they are out of context. (This is known as prosopagnosia.) Leaving his psychiatrist’s office one day, he prepares to leave the building and notices a soberly dressed man in the lobby. Only when the man greets him does he realize it’s his therapist! For Sacks, faces don’t “gel” but are a series of planes and discrete objects. (He uses tricks like a distinctive eyebrow or pair of glasses to recognize some friends.) In the right context, however, this condition, which he calls being “face-blind” abates. The condition also affects his sense of place, and Sacks gets lost easily, even in his own neighborhood. One time he passed his own building several times without realizing it.

On the other hand there is still a great deal of emphasis not on images or the visual, but language as the basis for thinking. Propositions, semantics, and “formal ontologies” abound for representing relationships, objects, and even space and geographies. But, since these are descriptive not experiential, can they be the whole story?

Sacks ends with a (deliciously) irresolvable paradox:

if there is indeed a fundamental difference between experience and description, between direct and mediated knowledge of the world, how is it that language can be so powerful? Language, that most human invention, can enable what, in principle, should not be possible. It can allow all of us, even the congenitally blind, to see with other people’s eyes.

A highly recommended book.

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