I recently read The Itch, by Atul Gawande in The New Yorker. This is how they describe an itch: “Its mysterious power may be a clue to a new theory about brains and bodies.” The article tells the story of a woman who had an itch on her forehead so unrelenting and uncontrollable that she scratched right through her skull and into her brain. But I’m not bringing this article to your attention simply for prurient gore-fest sake (although it is a great read). The article talks about a so-called “new” scientific understanding of perception. In short, this “new” theory is about the impoverished quality of the signals our senses send to our brains and how we construct reality by putting together what we think we know and match it to what we think we might be perceiving at the moment. In this case it explains the very real experience of phantom limbs in amputees, for instance.
The fallacy of reducing perception to reception is especially clear when it comes to phantom limbs. Doctors have often explained such sensations as a matter of inflamed or frayed nerve endings in the stump sending aberrant signals to the brain. But this explanation should long ago have been suspect. Efforts by surgeons to cut back on the nerve typically produce the same results that M. had when they cut the sensory nerve to her forehead: a brief period of relief followed by a return of the sensation.
And for me here’s the kicker:
The images in our mind are extraordinarily rich. We can tell if something is liquid or solid, heavy or light, dead or alive. But the information we work from is poor—a distorted, two-dimensional transmission with entire spots missing. So the mind fills in most of the picture. You can get a sense of this from brain-anatomy studies. If visual sensations were primarily received rather than constructed by the brain, you’d expect that most of the fibres going to the brain’s primary visual cortex would come from the retina. Instead, scientists have found that only twenty per cent do; eighty per cent come downward from regions of the brain governing functions like memory. Richard Gregory, a prominent British neuropsychologist, estimates that visual perception is more than ninety per cent memory and less than ten per cent sensory nerve signals. When Oaklander theorized that M.’s itch was endogenous, rather than generated by peripheral nerve signals, she was onto something important. [I’ve added the emphases.]
To me this “new” theory connects a bit with my last entry discussing the Line of Cognition from Plato written 2400 years ago. The New Yorker article quotes the 18th C. Idealist philosopher George Berkeley who had a famous row with Samuel Johnson (the Idealists were religious neo-Platonist who believed that objects in the world are an invention of the mind):
In a 1710 “Treatise Concerning the Principles of Human Knowledge,” the Irish philosopher George Berkeley objected to this view. We do not know the world of objects, he argued; we know only our mental ideas of objects. “Light and colours, heat and cold, extension and figures—in a word, the things we see and feel—what are they but so many sensations, notions, ideas?” Indeed, he concluded, the objects of the world are likely just inventions of the mind, put in there by God. To which Samuel Johnson famously responded by kicking a large stone and declaring, “I refute it thus!”
Still, Berkeley had recognized some serious flaws in the direct-perception theory—in the notion that when we see, hear, or feel we are just taking in the sights, sounds, and textures of the world.
I bring this up because even though I just came upon this Itch article, the parts I reference correlate strongly with a passage in the notes at the end of Oculus. An earlier edit of Oculus also contained a reference to the Berkeley kerfuffle and Johnson kicking the stone, but I removed it for the sake of brevity.
From the back notes in Oculus:
Part 4 Recognition Is Not Knowledge
On the nature of experience and memory
If seeing is not knowing, then it follows that recognition cannot be knowledge.
We take a small amount of information and extrapolate it into something we think we know. We recognize shapes in stains on the wall (as Leonardo da Vinci did), or see faces in burnt toast. The human brain is remarkably efficient at interpreting imagery from the most meager of data. We project meaning constantly, both publicly and privately, upon data streams that, at times, contain little or no information. And because of that, we don’t actually need to see perfectly to make our way in the world. Our vision relies heavily on our recognitions and interpretations. What we think something is, what it reminds us of, is paramount. And since we are social animals, living in a social environment, we are socially driven to consider what we see. We endlessly convey and discuss what we think we understand to settle upon what we believe we see and think we know to be true. This is how we define the world—to ourselves, for ourselves and for each other, serving very real social and practical purposes, deepening our social relations and helping us to make decisions about the world we confront.
The images we’ve retained in our memories, along with the beliefs we’ve surrounded them with, prepare us not only for what we are about to perceive, but also what significance our perceptions might provide. Our perceptions tend to confirm or inform our generally unverified (subjective) socially-derived worldviews. We infuse the world we encounter with meaning, with social and symbolic significance based on the value we place upon the representations we share. Adept at transforming the world into symbols and metaphors, references to reality are only a constituent part of our projections, and not of primary importance. We live in a world alive with magical thinking and magical projections. And our dreams and beliefs, our hopes, desires and emanations all play a vital rôle in our social relations. Our symbolic systems representing knowledge and belief, whether fact based or fantasy derived, both perform the same social function of informing our experience, of allowing us to share an appreciation of the infinite—or simply of what is at hand. And that is what we yearn for: a kind of certainty that yields, upon examination, to wonderment.
So while this might not be such a “new” theory, it may have gained some scientific relevancy of late. These are ideas that have been kicking around for a few thousand years or more. Maybe our philosophical ideas can be seen to be “more” right these days when corroborated by rigorous scientific observation and testing.