One way or another, I had worried about the death of brain cells since I was about ten, convinced year after year that I was getting more stupid; and when I began to drink in a small way, and the news broke (while I was in college) that an ounce of distilled spirits kills one thousand neurons (I think that was the ratio), the concern intensified. One weekend I confessed to my mother on the phone that I had been worrying that over the past six months especially, my brain wattage had dimmed perceptibly. She had always been interested in materialist analogies for cognition, and she offered reassurance, as I knew she would. “It’s true,” she said, “that your individual brain cells are dying, but the ones that stay grow more and more connections, and those connections keep branching out over the years, and that’s the progress you have to keep in mind. It’s the number of links that are important, not the raw number of cells.” This observation was exceeedingly helpful. In the week or two following her news that connections continued to proliferate in the midst of neural carnage, I formed several related theories:
(a) We begin, perhaps, with a brain that is much too crowded with processing capacity, and therefore the death of the brain cells is part of a _planned and necessary_ winnowing that precedes the move upward to higher levels of intelligence: the weak ones fizzle out, and the gaps they leave as they are reabsorbed stimulate the growth buds of dendrites, which now have more capacious playgrounds, and complex correlational structures come about as a result. (Or perhaps the dendrites’ own heightened need for space to grow forces a mating struggle: they lock antlers with feebler outriggers in the search for the informationally rich connections, shortcutting through intermediate territories and causing them to wither and shut down like neighbourhoods near a new thruway.) With fewer total cells, but more connections between each cell, the quality of your knowledge undergoes a transformation: you begin to have a feel for situations, people fall into types, your past memories link together, and your life begins to seem, as it hadn’t when you were younger, and inevitable thing composed of a million small failures and successes dependently intergrown, as opposed to a bright beadlike row of unaffiliated moments. Mathematicians needs all of those spare neurons, and their careers falter when the neurons do, but the rest of us should be thankful for their disappearance, for it makes room for experience. Depending on where on the range you began, you are shifted as your brain ages toward the richer, more mingled pole: mathematicians become philosophers, philosophers become historians, historians become biographers, biographers become college provosts, college provosts become political consultants, and political consultants run for office.
(b) Used with care, substances that harm neural tissue, such as alcohol, can aid intelligence: you corrode the chromium, giggly, crossword puzzle-solving parts of your mind with pain and poison, forcing the neurons to take responsibility for themselves and those around them, toughening themselves against the accelerated wear of these artificial solvents. After a night of poison, your brain wakes up in the morning saying, “No, I don’t give a shit who introduced the sweet potato into North America.” The damage that you have inflicted heals over, and the scarred places left behind have unusual surface areas, roughnesses enough to become the nodes around which wisdom weaves its fibrils.
(c) The neurons that do expire are the ones that make imitation possible. When you are capable of skillful imitation, the sweep of choices before you is too large; but when your brain loses its spare capacity, and along with it some agility, some joy in winging it, and the ambition to do things that don’t suit it, then you finally have to settle down to do well the few things that your brain really can do well - the rest no longer seems pressing and distracting, because it is now permanently out of reach. The feeling that you are stupider than you were is what finally interests you in the really complex subjects of life: in change, in experience, in the ways other people have adjusted to disappointment and narrowed ability. You realize that you are no prodigy, your shoulders relax, and you begin to look around you, seeing local color unrivaled by blue glows of algebra and abstraction.
(d) Individual ideas are injured along with the links over which they travel. As they are dismembered and remembered, damaged, forgotten, later refurbished, they become subtler, more hierarchical, tiered with half-obliterated particulars. When they molder or sustain damage, they regenerate more as a part of the self, and less as a part of an external system.
