evening to inform Gajdusek that he was mistaken about people not believing in the spirits of the dead as the cause of disease, and that he was further in error in holding that they had abandoned the idea of sorcery as the cause of yaws. The people held, he continued, that a dead body could become invisible and that the unseen spirit of the dead person could enter the skin of a patient at night through an imperceptible break, and induce yaws. The Australian’s informant had even sketched with a stick in the sand the appearance of these ghostly beings. They carefully drew a circle and a few squiggly lines within. Outside the circle, they explained, it was black; inside the circle, bright-a sand portrait of malevolent and pathogenic spirits.
Upon inquiry of the young translator, Gajdusek discovered that the Australian physician had conversed with some of the older men of the village who were well known to Gajdusek and who were often his house and laboratory guests. They had attempted to explain that the shape of the “germ” producing yaws was spiral-the spirochete form they had seen many times through Gajdusek’s dark-field microscope. They had to admit it was invisible-it could be seen only through the microscope-and when pressed by the Australian physician on whether this “represented” the dead person, they had to admit that Gajdusek had stressed that it could be caught from close contact with yaws lesions, as, for example, by sleeping with a person with yaws.
I can well remember the first time I looked through a microscope. After focusing my eyes up near the ocular only to examine my eyelashes, and then peering further into the pitch-black interior of the barrel, I finally managed to look straight down the microscope tube to be dazzled by an illuminated disc of light. It takes a little while for the eye to train itself to examine what is in the disc. Gajdusek’s demonstration to the Fore people was so powerful- after all, the alternatives entirely lacked so concrete a reality-that many accepted his story, even apart from his ability to cure the disease with penicillin. Perhaps some considered the spirochetes in the microscope an amusing example of white-man myth and minor magic, and when another white man arrived querying the origin of disease, they politely returned to him the idea they believed he would be comfortable with. Had Western contact with the Fore people ceased for fifty years, it seems to me entirely possible that a future visitor would discover to his astonishment that the Fore people somehow had knowledge of medical microbiology, despite their largely pretechnological culture.
All three of these stories underline the almost inevitable problems encountered in trying to extract from a “primitive” people their ancient legends. Can you be sure that others have not come before you and destroyed the pristine state of the native myth? Can you be sure that the natives are not humoring you or pulling your leg? Bronislaw Malinowski thought he had discovered a people in the Trobriand Islands who had not worked out the connection between sexual intercourse and childbirth. When asked how children were conceived, they supplied him with an elaborate mythic structure prominently featuring celestial intervention. Amazed, Malinowski objected that was not how it was done at all, and supplied them instead with the version so popular in the West today-including a nine-month gestation period. “Impossible,” replied the Melanesians. “Do you not see that woman over there with her six-month-old child? Her husband has been on an extended voyage to another island for two years.” Is it more likely that the Melanesians were ignorant of the begetting of children or that they were gently chiding Malinowski? If some peculiar-looking stranger came into my town and asked
I wonder if the Dogon, having heard from a Westerner an extraordinarily inventive myth about the star Sirius-a star already important in their own mythology-did not carefully play it back to the visiting French anthropologist. Is this not more likely than a visit by extraterrestrial spacefarers to ancient Egypt, with one cluster of hard scientific knowledge, in striking contradiction to common sense, preserved by oral tradition, over the millennia, and only in West Africa?
There are too many loopholes, too many alternative explanations for such a myth to provide reliable evidence of past extraterrestrial contact. If there are extraterrestrials, I think it much more likely that unmanned planetary spacecraft and large radiotelescopes will prove to be the means of their detection.
CHAPTER 7
When the movement of the comets is considered and we reflect on the laws of gravity, it will be readily perceived that their approach to the Earth might there cause the most woeful events, bring back the universal deluge, or make it perish in a deluge of fire, shatter it into small dust, or at least turn it from its orbit, drive away its Moon, or, still worse, the Earth itself outside the orbit of Saturn, and inflict upon us a winter several centuries long, which neither men nor animals would be able to bear. The tails even of comets would not be unimportant phenomena, if the comets in taking their departure left them in whole or in part in our atmosphere.
J. H. LAMBERT,
However dangerous might be the shock of a comet, it might be so slight, that it would only do damage at the part of the Earth where it actually struck; perhaps even we might cry quits if while one kingdom were devastated, the rest of the Earth were to enjoy the rarities which a body which came from so far might bring to it. Perhaps we should be very surprised to find that the debris of these masses that we despised were formed of gold and diamonds; but who would be the most astonished, we, or the comet-dwellers, who would be cast on our Earth? What strange beings each would find the other!
MAUPERTUIS,
SCIENTISTS, like other human beings, have their hopes and fears, their passions and despondencies-and their strong emotions may sometimes interrupt the course of clear thinking and sound practice. But science is also self- correcting. The most fundamental axioms and conclusions may be challenged. The prevailing hypotheses must survive confrontation with observation. Appeals to authority are impermissible. The steps in a reasoned argument must be set out for all to see. Experiments must be reproducible.
The history of science is full of cases where previously accepted theories and hypotheses have been entirely overthrown, to be replaced by new ideas that more adequately explain the data. While there is an understandable psychological inertia-usually lasting about one generation-such revolutions in scientific thought are widely accepted as a necessary and desirable element of scientific progress. Indeed, the reasoned criticism of a prevailing belief is a service to the proponents of that belief; if they are incapable of defending it, they are well advised to abandon it. This self-questioning and error-correcting aspect of the scientific method is its most striking property, and sets it off from many other areas of human endeavor where credulity is the rule.
The idea of science as a method rather than as a body of knowledge is not widely appreciated outside of science, or indeed in some corridors inside of science. For this reason I and some of my colleagues in the American Association for the Advancement of Science have advocated a regular set of discussions at the annual AAAS meeting of hypotheses that are on the borderlines of science and that have attracted substantial public interest. The idea is not to attempt to settle such issues definitively, but rather to illustrate the process of reasoned disputation, to show how scientists approach a problem that does not lend itself to crisp experimentation, or is unorthodox in its interdisciplinary nature, or otherwise evokes strong emotions.
Vigorous criticism of new ideas is a commonplace in science. While the style of the critique may vary with the
