The Evolution of Man
Darwin for Today
The Tangled Bank: Darwin, Marx, Frazier, Freud as Imaginative Writers
A recent issue of the Times Literary Supplement has excited considerable attention because of a long article by C.P. Snow, a rebuttal to the critics of Two Cultures. The article is dignified, reasonable, and entirely predictable, essentially a pièce justificative, adding nothing new to the controversy or to the original essay apart from the substitution of DNA for the Second Law of Thermodynamics as a test of scientific literacy. The rest of the issue, however, is more noteworthy. Entitled “The Art of Science,” it may be taken as a subtle rebuke to Sir Charles and a corrective to the popular image of the Two Cultures—a scientific culture that is essentially rational, logical, and evidential, and a literary culture that is essentially intuitive, emotive, and imaginative. What the TLS is now suggesting is that the scientific enterprise itself is, at its best, a kind of art, and that the two cultures have more in common than is generally thought.
The theme is best stated in the article “Imagination and Hypothesis” by Dr. P.B. Medawar, the distinguished English biologist, Nobel Prize winner, and director of the National Institute for Medical Research. Dr. Medawar refutes five of the most commonly accepted myths about science: the myth of a “scientific mind,” of “the scientific method,” of observation and deduction à la Bacon, of induction à la Mill, and of a “natural law” arrived at by rational, objective processes. Dr. Medawar concludes:
Scientists and laymen should become aware of the inspirational character of scientific discovery and of the hypothetico-deductive foundation upon which scientific understanding rests…. At every level of endeavor scientific research is a passionate undertaking, and the Promotion of Natural Knowledge depends above all else upon a sortie into what can be imagined but is not yet known.
The following article, “Portrait of the Scientist as Artist,” makes much the same point. The Professor of Chemistry at Cambridge, H.C. Longuet-Higgins, agrees that “the scientist is by nature an artist,” that “his ways of thought are primarily intuitive and imaginative,” and that the fiction of a “scientific method” was invented to “account for the unaccountable: the demonstrable capacity of the human mind to create ideas out of the void and to discriminate between the significant and the trivial.”
There should be no need to remind us, as Dr. Medawar does, that “hypothesis” and “imagination” are not pejorative words. We do, however, have to be reminded that they introduce a problematic quality into science. Science does not merely accumulate certainties; it also accumulates uncertainties. The more science knows, the more it knows how little it knows. Yet the desire for certainty is so pervasive that even scientists succumb to the popular superstitions of science.
As if to dramatize this point, the same issue of the TLS contains a perfect specimen of the pseudo-scientific mentality, in which hypothesis and imagination of a not particularly distinguished order are given far more authority than they merit. The example is the more egregious because it occurs in an area of science that is, or should be, at every moment acutely aware of the fragile, fragmentary, and tentative nature of its hypotheses. The review is of a book by Richard Carrington on The Million Years of Man which, according to the reviewer, starts with the stellar universe and the history of the earth, goes through the “probable evolution of life,” describes the development of man, mind, and civilization, and concludes with a chapter on the future of “human destiny and the individual.” Whether the author makes more of the “probable” character of these wide-ranging deductions I do not know. But the reviewer takes issue with him on only two points—the interpretation of the Paleolithic cave paintings and the future of humanity. For the rest the reviewer has only praise, singling out for special commendation the “charming reconstructions of prehistoric scenes, especially one of a Mesolithic riverside settlement where the girls are wearing clothes that look remarkably like modern gym tunics.”
American anthropologists and museum curators tend to clothe their prehistoric women in sarongs rather than gym tunics, but they produce equally charming and confident reconstructions. Evolution, a recent addition to the “Life Nature Library,” has illustrations and text in the same glossy finish and sharp focus, the brilliance of the photographs conspiring with the lucidity of the prose to induce in the reader a state of hypnotic acquiescence. There are, for example, sketches of the faces of the shark, lizard, opossum, lemur, monkey, gorilla, and man, accompanied by the explanation that in these “successive stages” of progress, “the eyes work their way to the front of the head for true binocular vision” and “the head becomes increasingly spherical—the most efficient shape for maximum brain in minimum skull.” The pictures and captions fit so neatly together that it is a shame to be reminded of Von Helmholtz’s remark that the human eye had “every possible defect that can be found in an optical instrument, and even some which are peculiar to itself”; or of Dr. Medawar’s complaint, in an earlier article, that the entire human structure is sadly deficient in many respects. The “successive stages” of progress that Life attributes to organic life may be neither so successive nor so progressive as this or any other tidy scheme would have it.
It also seems presumptuous to point out to Ruth Moore and the editors of Life (who are jointly listed as the authors of this book, in consultation with various professors and curators) that the process of reconstructing a head from fragments of bone is considerably less certain and precise than is here made out. Miss Moore, indeed, has good reason to appreciate just how uncertain and imprecise (not in details but in crucial respects) such reconstructions may be. It is generally regarded as bad form to make too much of the Piltdown fraud, and the Life book casually dismisses it as a “find which many years later embarrassingly turned out to be a hoax.” Yet Miss Moore herself was unfortunate enough, on the very eve of its exposure as a fraud, to have published a book in which Piltdown man was given pride of place in the human lineage. And then, as now, Miss Moore was only reflecting the best scientific opinion. For forty years, until less than ten years ago, some of the most eminent paleontologists in the world not only gave credence to what Miss Moore euphemistically describes as a “hoax,” but soberly argued the merits of various reconstructions of a skull combining a modern human brain with an ancient ape jaw, performed anatomical experiments demonstrating the exact muscular changes that must have taken place in the evolutionary process, and proved mathematically that the required changes could well have taken place in the available period of time. Neither Miss Moore nor even the paleontologists most deeply committed to particular interpretations of Piltdown man seem to have learnt much from the experience, and the present volume is full of the same kind of confident assertions based on the same kind of evidence—evidence that may or may not be true, that may or may not be relevant.
If it is suggested that a Life book or a museum exhibit is too easy a mark, a recently translated work by one of the world’s leading paleontologists, G. H.R. von Koeningswald’s Evolution of Man, can be taken in illustration. What is conspicuous here are not the glib certitudes of the popularizer, but the practical dilemmas of the conscientious working scientist. Almost every page provides evidence of the infinitely complicated and problematic state of paleontology:
As we can see, paleontologists base their classifications chiefly on the canine-premolar section of the jaw, which is far too frequently missing. Added to this is the difficulty that no one is quite certain of the form of the original human canine. Hence types with large canines are far too readily classified as pongids [simians], on the unwarranted assumption that the teeth of modern apes can be used as a general criterion.
A great difficulty arises from the claim that, since australo-pithecines made fire and tools, they must be considered full “men.” We saw that Dart called his Makapan specimen Australo-pithecus prometheus, the fire-raiser, because of the charcoal near him. However, the mere discovery of pieces of charcoal does not entitle us to say that they were produced by men, for spontaneous bushfires are a far more likely explanation.
More equivocal still is the tool problem. No matter what the real explanation of the strange indentations on baboon skulls may be, they were certainly not caused in the way Dart has suggested. According to him, a number of evenly damaged humeri must have been used as percussion instruments, but we agree with Zapfe that the damage was more probably caused by byenas.
Unfortunately we know nothing about the Pleistocene ancestry of either the gorilla or the chimpanzee, and little about their possible relationship with Tertiary European types. The only species whose prehistory is known to any extent is the orangutan.
The evolution of the rest of the skeleton [apart from the jaw] can be reviewed very briefly—very little is known about it.
Yet the book is as prolifie in unwarranted assumptions and contradictions as in qualifications and cautions. The first quotation cited above, for example, on our ignorance of the “form of the original human canine,” is followed immediately by the statement: “Sivapithecus was said by Pilgrim to be related to man, but its large canines make this classification doubtful”!
Of all scientists it is the scientist turned historian who is most readily victimized by the myths described by Dr. Medawar. An intellectual regression seems to set in as soon as the scientist regresses into history. That the scientist is not the most reliable guide to his own history—nor, perhaps, the best arbiter between the Two Cultures—is suggested by the avalanche of Darwiniana released by the centenary of the Origin of Species four years ago, when some of the most estimable scientists were responsible for some of the most mindless pieties.
On the other hand, recent weeks have seen the appearance of three volumes of selections from the works of leading protagonists in the original Darwinian controversy, each volume well chosen, well edited, and provocative, both in their introductions and texts. One was edited by a historian, the other two by literary critics whose more normal medium is the Hudson Review or Kenyon Review. The three volumes, apart from the suggestive circumstances of their editing, provide a fascinating exercise in dialectic, and their simultaneous publication is providential for the reviewer. Asa Gray was Darwin’s chief supporter in America; Louis Agassiz was Darwin’s—and Gray’s—chief critic in America; and Darwin himself was ambivalent towards Gray’s main thesis while being curiously dependent upon one of Agassiz’ main theories. The complications and anomalies revealed in these volumes go far to undermine both the conventional view of Scientific Method and the conventional reading of scientific history.