Broca's Brain: The Romance of Science

These forgotten jars and their grisly contents had been collected, at least partly, in a humanistic spirit; and perhaps, in some era of future advance in brain studies, they would prove useful once again. I would be interested in knowing a little more about the redmustachioed man who had been, in part, returned to France from New Caledonia.

But the surroundings, the sense of a chamber of horrors, evoked unbidden other unsettling thoughts. At the very least, we feel in such a place a pang of sympathy for those-especially those who died young or in pain-who are in so unseemly a way thus memorialized. Cannibals in northwestern New Guinea employ stacked skulls for doorposts, and sometimes for lintels. Perhaps these are the most convenient building materials available, but the architects cannot be entirely unaware of the terror that their constructions evoke in unsuspecting passers-by. Skulls have been used by Hitler’s SS, Hell’s Angels, shamans, pirates, and even those who label bottles of iodine, in a conscious effort to elicit terror. And it makes perfectly good sense. If I find myself in a room filled with skulls, it is likely that there is someone nearby, perhaps a pack of hyenas, perhaps some gaunt and dedicated decapitator, whose occupation or hobby it is to collect skulls. Such fellows are almost certainly to be avoided, or, if possible, killed. The prickle of the hairs on the back of my neck, the increased heartbeat and pulse rate, that strange, clammy feeling are designed by evolution to make me fight or flee. Those who avoid decapitation leave more offspring. Experiencing such fears bestows an evolutionary advantage. Finding yourself in a room full of brains is still more horrifying, as if some unspeakable moral monster, armed with ghastly blades and scooping tools, were shuffling and drooling somewhere in the attics of the Musee de l’Homme.

But all depends, I think, on the purpose of the collection. If its objective is to find out, if it has acquired human parts post mortem-especially with the prior consent of those to whom the parts once belonged-then little harm has been done, and perhaps in the long run some significant human good. But I am not sure the scientists are entirely free of the motives of those New Guinea cannibals; are they not at least saying, “I live with these heads every day. They don’t bother me. Why should you be so squeamish?”?

LEONARDO AND VESALIUS were reduced to bribery and stealth in order to perform the first systematic dissections of human beings in Europe, although there had been a flourishing and competent school of anatomy in ancient Greece. The first person to locate, on the basis of neuroanatomy, human intelligence in the head was Herophilus of Chalcedon, who flourished around 300 B.C. He was also the first to distinguish the motor from the sensory nerves, and performed the most thorough study of brain anatomy attempted until the Renaissance. Undoubtedly there were those who objected to his gruesome experimental predilections. There is a lurking fear, made explicit in the Faust legend, that some things are not “meant” to be known, that some inquiries are too dangerous for human beings to make. And in our own age, the development of nuclear weapons may, if we are unlucky or unwise, turn out to be a case of precisely this sort. But in the case of experiments on the brain, our fears are less intellectual. They run deeper into our evolutionary past. They call up images of the wild boars and highwaymen who would terrorize travelers and rural populations in ancient Greece, by Procrustean mutilation or other savagery, until some hero-Theseus or Hercules-would effortlessly dispatch them. These fears have served an adaptive and useful function in the past. But I believe they are mostly emotional baggage in the present. I was interested, as a scientist who has written about the brain, to find such revulsions hiding in me, to be revealed for my inspection in Broca’s collection. These fears are worth fighting.

All inquiries carry with them some element of risk. There is no guarantee that the universe will conform to our predispositions. But I do not see how we can deal with the universe-both the outside and the inside universe- without studying it. The best way to avoid abuses is for the populace in general to be scientifically literate, to understand the implications of such investigations. In exchange for freedom of inquiry, scientists are obliged to explain their work. If science is considered a closed priesthood, too difficult and arcane for the average person to understand, the dangers of abuse are greater. But if science is a topic of general interest and concern-if both its delights and its social consequences are discussed regularly and competently in the schools, the press, and at the dinner table-we have greatly improved our prospects for learning how the world really is and for improving both it and us. That is an idea, I sometimes fancy, that may be sitting there still, sluggish with formalin, in Broca’s brain.

CHAPTER 2

CAN WE KNOW THE UNIVERSE?

REFLECTIONS ON A GRAIN OF SALT

Nothing is rich but the inexhaustible wealth

of nature. She shows us only surfaces,

but she is a million fathoms deep.

RALPH WALDO EMERSON

SCIENCE IS A WAY of thinking much more than it is a body of knowledge. Its goal is to find out how the world works, to seek what regularities there may be, to penetrate to the connections of things-from subnuclear particles, which may be the constituents of all matter, to living organisms, the human social community, and thence to the cosmos as a whole. Our intuition is by no means an infallible guide. Our perceptions may be distorted by training and prejudice or merely because of the limitations of our sense organs, which, of course, perceive directly but a small fraction of the phenomena of the world. Even so straightforward a question as whether in the absence of friction a pound of lead falls faster than a gram of fluff was answered incorrectly by Aristotle and almost everyone else before the time of Galileo. Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage-at the very least the courage to question the conventional wisdom.

Beyond this the main trick of science is to really think of something: the shape of clouds and their occasional sharp bottom edges at the same altitude everywhere in the sky; the formation of a dewdrop on a leaf; the origin of a name or a word-Shakespeare, say, or “philanthropic”; the reason for human social customs-the incest taboo, for example; how it is that a lens in sunlight can make paper burn; how a “walking stick” got to look so much like a twig; why the Moon seems to follow us as we walk; what prevents us from digging a hole down to the center of the Earth; what the definition is of “down” on a spherical Earth; how it is possible for the body to convert yesterday’s lunch into today’s muscle and sinew; or how far is up-does the universe go on forever, or if it does not, is there any meaning to the question of what lies on the other side? Some of these questions are pretty easy. Others, especially the last, are mysteries to which no one even today knows the answer. They are natural questions to ask. Every culture has posed such questions in one way or another. Almost always the proposed answers are in the nature of “Just So Stories,” attempted explanations divorced from experiment, or even from careful comparative observations.

But the scientific cast of mind examines the world critically as if many alternative worlds might exist, as if other things might be here which are not. Then we are forced to ask why what we see is present and not something else. Why are the Sun and the Moon and the planets spheres? Why not pyramids, or cubes, or dodecahedra? Why not irregular, jumbly shapes? Why so symmetrical, worlds? If you spend any time spinning hypotheses, checking to see whether they make sense, whether they conform to what else we know, thinking of tests you can pose to substantiate or deflate your hypotheses, you will find yourself doing science. And as you come to practice this habit of thought more and more you will get better and better at it. To penetrate into the heart of the thing-even a little thing, a blade of grass, as Walt Whitman said-is to experience a kind of exhilaration that, it may be, only human beings of all the beings on this planet can feel. We are an intelligent species and the use of our intelligence quite