Broca's Brain: The Romance of Science
Carl Sagan
Broca's Brain: The Romance of Science
Carl Sagan
Carl Sagan, writer and scientist, returns from the frontier to tell us about how the world works. In his delightfully down-to-earth style, he explores and explains a mind-boggling future of intelligent robots, extraterrestrial life and its consquences, and other provocative, fascinating quandries of the future that we want to see today.
Carl Sagan
Broca's Brain: The Romance of Science
© 1979
To Rachel and Samuel Sagan, my parents,
who introduced me to the joys of understanding
the world, with gratitude and admiration and love
ACKNOWLEDGMENTS
FOR DISCUSSION on specific points I am grateful to a number of friends, correspondents and colleagues, including Diane Ackerman, D. W. G. Arthur, James Bakalar, Richard Berendzen, Norman Bloom, C. Chandrasekhar, Clark Chapman, Sidney Coleman, Yves Coppens, Judy-Lynn Del Rey, Frank Drake, Stuart Edelstein, Paul Fox, D. Carleton Gajdusek, Owen Gingerich, Thomas Gold, J. Richard Gott III, Steven J. Gould, Lester Grinspoon, Stanislav Grof, J. U. Gunter, Robert Horvitz, James W. Kalat, B. Gentry Lee, Jack Lewis, Marvin Minsky, David Morrison, Philip Morrison, Bruce Murray, Phileo Nash, Tobias Owen, James Pollack, James Randi, E. E. Salpeter, Stuart Shapiro, Gunther Stent, O. B. Toon, Joseph Veverka, E. A. Whitaker and A. Thomas Young.
This book owes much, in all stages of production, to the dedicated and competent efforts of Susan Lang, Carol Lane, and, particularly, my executive assistant, Shirley Arden.
I am especially grateful to Ann Druyan and Steven Soter for generous encouragement and stimulating commentary on a great many of the subjects of this book. Ann has made essential contributions to most chapters and to the title; my debt to her is very great.
INTRODUCTION
WE LIVE in an extraordinary age. These are times of stunning changes in social organization, economic wellbeing, moral and ethical precepts, philosophical and religious perspectives, and human self-knowledge, as well as in our understanding of that vast universe in which we are imbedded like a grain of sand in a cosmic ocean. As long as there have been human beings, we have posed the deep and fundamental questions, which evoke wonder and stir us into at least a tentative and trembling awareness, questions on the origins of consciousness; life on our planet; the beginnings of the Earth; the formation of the Sun; the possibility of intelligent beings somewhere up there in the depths of the sky; as well as, the grandest inquiry of all-on the advent, nature and ultimate destiny of the universe. For all but the last instant of human history these issues have been the exclusive province of philosophers and poets, shamans and theologians. The diverse and mutually contradictory answers offered demonstrate that few of the proposed solutions have been correct. But today, as a result of knowledge painfully extracted from nature, through generations of careful thinking, observing and experimenting, we are on the verge of glimpsing at least preliminary answers to many of these questions.
There are a number of themes that weave through the structure of this book, appearing early, disappearing for a few chapters, and then resurfacing in a somewhat different context-including the joys and social consequences of the scientific endeavor; borderline or pop science; the not entirely different subject of religious doctrine; the exploration of the planets and the search for extraterrestrial life; and Albert Einstein, in the centenary of whose birth this book is published. Most of the chapters can be read independently, but the ideas have been presented in an order chosen with some care. As in some of my previous books, I have not hesitated to interject social, political or historical remarks where I thought they might be appropriate. The attention given to borderline science may seem curious to some readers. Practitioners of pop science were once called Paradoxers, a quaint nineteenth-century word used to describe those who invent elaborate and undemonstrated explanations for what science has understood rather well in simpler terms. We are today awash with Paradoxers. The usual practice of scientists is to ignore them, hoping they will go away. I thought it might be useful-or at least interesting-to examine the contentions and conceits of some Paradoxers a little more closely, and to connect and contrast their doctrines with other belief systems, both scientific and religious.
Both borderline science and many religions are motivated in part by a serious concern about the nature of the universe and our role in it, and for this reason merit our consideration and regard. In addition, I think it possible that many religions involve at their cores an attempt to come to grips with profound mysteries of our individual life histories, as described in the last chapter. But both in borderline science and in organized religion there is much that is specious or dangerous. While the practitioners of such doctrines often wish there were no criticisms to which they are expected to reply, skeptical scrutiny is the means, in both science and religion, by which deep insights can be winnowed from deep nonsense. I hope my critical remarks in these pages will be recognized as constructive in intent. The well-meaning contention that all ideas have equal merit seems to me little different from the disastrous contention that no ideas have any merit.
This book, then, is about the exploration of the universe and ourselves; that is, it is about science. The range of topics may seem very diverse-from a crystal of salt to the structure of the cosmos, myth and legend, birth and death, robots and climates, the exploration of the planets, the nature of intelligence, the search for life beyond the Earth. But, as I hope will emerge, these topics are connected because the world is connected, and also because human beings perceive the world through similar sense organs and brains and experiences that may not reflect the external realities with absolute fidelity.
Each chapter of Broca’s Brain is written for a general audience. In a few places-such as “Venus and Dr. Velikovsky,” “Norman Bloom, Messenger of God,” “Experiments in Space” and “The Past and Future of American Astronomy”-I have included an occasional technical detail; but understanding such details is not necessary for understanding the overall flow of the discussion.
Some of the ideas in Chapters 1 and 25 were first presented in my William Menninger Memorial Lecture to the American Psychiatric Association in Atlanta, Georgia, in May 1978. Chapter 16 is based on a banquet address at the annual meeting of the National Space Club, Washington, D.C., April 1977; Chapter 18 on an address at a symposium, commemorating the first liquid-fuel rocket flight, held at the Smithsonian Institution, Washington, D.C., March 1976; Chapter 23 on a sermon delivered at the Sage Chapel Convocation, Cornell University, November 1977; and Chapter 7 on a talk at the annual meeting of the American Association for the Advancement of Science, February 1974.
This book is written just before-at most, I believe, a few years or a few decades before-the answers to many of those vexing and awesome questions on origins and fates are pried loose from the cosmos. If we do not destroy ourselves, most of us will be around for the answers. Had we been born fifty years earlier, we could have wondered, pondered, speculated about these issues, but we could have done nothing about them. Had we been born fifty years later, the answers would, I think, already have been in. Our children will have been taught the answers before most of them will have had an opportunity even to formulate the questions. By far the most exciting, satisfying and exhilarating time to be alive is the time in which we pass from ignorance to knowledge on these fundamental issues; the age where we begin in wonder and end in understanding. In all of the four-billion-year history of life on our planet, in all of the four-million-year history of the human family, there is only one generation privileged to live through that unique transitional moment: that generation is ours.
Ithaca, New Yo
rk
October 1978
PART I. SCIENCE AND HUMAN CONCERN
CHAPTER 1
BROCA’S BRAIN
“They were apes only yesterday.
Give them time.”
“Once an ape-always an ape.”…
“No, it will be different… Come back here in
an age or so and you shall see…”
The gods, discussing the Earth, in the motion
picture version of H. G. Wells’ The Man Who
Could Work Miracles (1936)
IT WAS A MUSEUM, in a way like any other, this Musée de l’Homme, Museum of Man, situated on a pleasant eminence with, from the restaurant plaza in back, a splendid view of the Eiffel Tower. We were there to talk with Yves Coppens, the able associate director of the museum and a distinguished paleoanthropologist. Coppens had studied the ancestors of mankind, their fossils being found in Olduvai Gorge and Lake Turkana, in Kenya and Tanzania and Ethiopia. Two million years ago there were four-foot-high creatures, whom we call Homo habilis, living in East Africa, shearing and chipping and flaking stone tools, perhaps building simple dwellings, their brains in the course of a spectacular enlargement that would lead one day-to us.
Institutions of this sort have a public and a private side. The public side includes the exhibits in ethnography, say, or cultural anthropology: the costumes of the Mongols, or bark cloths painted by Native Americans, some perhaps prepared especially for sale to voyageurs and enterprising French anthropologists. But in the innards of the place there are other things: people engaged in the construction of exhibits; vast storerooms of items inappropriate, because of subject matter or space, for general exhibition; and areas for research. We were led through a warren of dark, musty rooms, ranging from cubicles to rotundas. Research materials overflowed into the corridors: a reconstruction of a Paleolithic cave floor, showing where the antelope bones had been thrown after eating. Priapic wooden statuary from Melanesia. Delicately painted eating utensils. Grotesque ceremonial masks. Assagai-like throwing spears from Oceania. A tattered poster of a steatopygous woman from Africa. A dank and gloomy storeroom filled to the rafters with gourd woodwinds, skin drums, reed panpipes and innumerable other reminders of the indomitable human urge to make music.
Here and there could be found a few people actually engaged in research, their sallow and deferential demeanors contrasting starkly with the hearty bilingual competence of Coppens. Most of the rooms were evidently used for storage of anthropological items, collected from decades to more than a century ago. You had the sense of a museum of the second order, in which were stored not so much materials that might be of interest as materials that had once been of interest. You could feel the presence of nineteenth-century museum directors engaged, in their frock coats, in goniométrie and craniologie, busily collecting and measuring everything, in the pious hope that mere quantification would lead to understanding.
But there was another area of the museum still more remote, a strange mix of active research and virtually abandoned cabinets and shelves. A reconstructed and articulating skeleton of an orangutan. A vast table covered with human skulls, each neatly indexed. A drawer full of femurs, piled in disarray, like the erasers in some school janitor’s supply closet. A province dedicated to Neanderthal remains, including the first Neanderthal skull, reconstructed by Marcellin Boule, which I held cautiously in my hands. It felt lightweight and delicate, the sutures starkly visible, perhaps the first compelling piece of evidence that there once were creatures rather like us who became extinct, a disquieting hint that our species likewise might not survive forever. A tray filled with the teeth of many hominids, including the great nutcracker molars of Australopithecus robustus, a contemporary of Homo habilis. A collection of Cro-Magnon skull cases, stacked like cordwood, scrubbed white and in good order. These items were reasonable and in a way expected, the necessary shards of evidence for reconstructing something of the history of our ancestors and collateral relatives.
Deeper in the room were more macabre and more disturbing collections. Two shrunken heads reposing on a cabinet, sneering and grimacing, their leathery lips curled back to reveal rows of sharp, tiny teeth. Jar upon jar of human embryos and fetuses, pale white, bathed in a murky greenish fluid, each jar competently labeled. Most specimens were normal, but occasionally an anomaly could be glimpsed, a disconcerting teratology-Siamese twins joined at the sternum, say, or a fetus with two heads, the four eyes tightly shut.
There was more. An array of large cylindrical bottles containing, to my astonishment, perfectly preserved human heads. A red-mustachioed man, perhaps in his early twenties, originating, so the label said, from Nouvelle Calédonie. Perhaps he was a sailor who had jumped ship in the tropics only to be captured and executed, his head involuntarily drafted in the cause of science. Except he was not being studied; he was only being neglected, among the other severed heads. A sweet-faced and delicate little girl of perhaps four years, her pink coral earrings and necklace still perfectly preserved. Three infant heads, sharing the same bottle, perhaps as an economy measure. Men and women and children of both sexes and many races, decapitated, their heads shipped to France only to moulder-perhaps after some brief initial study-in the Musée de l’Homme. What, I wondered, must the loading of the crates of bottled heads have been like? Did the ship’s officers speculate over coffee about what was down in the hold? Were the sailors heedless because the heads were, by and large, not those of white Europeans like themselves? Did they joke about their cargo to demonstrate some emotional distance from the little twinge of horror they privately permitted themselves to feel? When the collections arrived in Paris, were the scientists brisk and businesslike, giving orders to the draymen on the disposition of severed heads? Were they impatient to unseal the bottles and embrace the contents with calipers? Did the man responsible for this collection, whoever he might be, view it with unalloyed pride and zest?
And then in a still more remote corner of this wing of the museum was revealed a collection of gray, convoluted objects, stored in formalin to retard spoilage-shelf upon shelf of human brains. There must have been someone whose job it was to perform routine craniotomies on the cadavers of notables and extract their brains for the benefit of science. Here was the cerebrum of a European intellectual who had achieved momentary renown before fading into the obscurity of this dusty shelf. Here a brain of a convicted murderer. Doubtless the savants of earlier days had hoped there might be some anomaly, some telltale sign in the brain anatomy or cranial configuration of murderers. Perhaps they had hoped that murder was a matter of heredity and not society. Phrenology was a graceless nineteenth-century aberration. I could hear my friend Ann Druyan saying, “The people we starve and torture have an unsociable tendency to steal and murder. We think it’s because their brows overhang.” But the brains of murderers and savants-the remains of Albert Einstein’s brain are floating wanly in a bottle in Wichita-are indistinguishable. It is, very probably, society and not heredity that makes criminals.
While scanning the collection amid such ruminations, my eye was caught by a label on one of the many low cylindrical bottles. I took the container from the shelf and examined it more closely. The label read P. Broca. In my hands was Broca’s brain.
PAUL BROCA was a surgeon, a neurologist and an anthropologist, a major figure in the development of both medicine and anthropology in the mid-nineteenth century. He performed distinguished work on cancer pathology and the treatment of aneurisms, and made a landmark contribution to understanding the origins of aphasia-an impairment of the ability to articulate ideas. Broca was a brilliant and compassionate man. He was concerned with medical care for the poor. Under cover of darkness, at the risk of his own life, he successfully smuggled out of Paris in a horse-drawn cart 73 million francs, stuffed into carpetbags and hidden under potatoes, the treasury of the Assistance Publique which-he believed, at any rate-he was saving from pillage. He was the founder of modern brain surgery. He studied infant mortality. Toward the e
nd of his career he was created a senator.
He loved, as one biographer said, mainly serenity and tolerance. In 1848 he founded a society of “freethinkers.” Almost alone among French savants of the time, he was sympathetic to Charles Darwin’s idea of evolution by natural selection. T. H. Huxley, “Darwin’s Bulldog,” remarked that the mere mention of Broca’s name filled him with a sense of gratitude, and Broca was quoted as saying, “I would rather be a transformed ape than a degenerate son of Adam.” For these and other views he was publicly denounced for “materialism” and, like Socrates, for corrupting the young. But he was made a senator nevertheless.
Earlier, Broca had encountered great difficulty in establishing a society of anthropology in France. The Minister of Public Instruction and the Prefect of Police believed that anthropology must, as the free pursuit of knowledge about human beings, be innately subversive to the state. When permission was at last and reluctantly granted for Broca to talk about science with eighteen colleagues, the Prefect of Police held Broca responsible personally for all that might be said in such meetings “against society, religion, or the government.” Even so, the study of human beings was considered so dangerous that a police spy in plain clothes was assigned to attend all meetings, with the understanding that authorization to meet would be withdrawn immediately if the spy was offended by anything that was said. In these circumstances the Society of Anthropology of Paris gathered for the first time on May 19, 1859, the year of the publication of The Origin of Species. In subsequent meetings an enormous range of subjects was discussed-archaeology, mythology, physiology, anatomy, medicine, psychology, linguistics and history-and it is easy to imagine the police spy nodding off in the corner on many an occasion. Once, Broca related, the spy wished to take a small unauthorized walk and asked if he might leave without anything threatening to the state being said in his absence. “No, no, my friend,” Broca responded. “You must not go for a walk: sit down and earn your pay.” Not only the police but also the clergy opposed the development of anthropology in France, and in 1876 the Roman Catholic political party organized a major campaign against the teaching of the subject in the Anthropological Institute of Paris founded by Broca.
