New Patterns in Genetics and Development
The Nature of Life
The Life of the Cell: Its Nature, Origin and Basic Development
The Biochemical Approach to Life
Genetics and Man
Heredity and the Nature of Man
These days, DNA and RNA are news. The fame of these “nucleic acids”—so significant for contemporary genetics—is a curious fact, and one that takes some explaining; but it should not (I believe) be considered in isolation. For, if we look back over the last ten or fifteen years, we can see that it is only one aspect of a more widespread change, which in different ways affects the whole style of contemporary life and thought. To be deliberately sweeping: if the dominant sciences (and sources of influence) during the first half of the twentieth century were mathematical and physical ones, the second half of the century (by contrast) looks like being a biological age.
On the strictly scientific level, the change is unquestionable. The most significant advances in our understanding of the natural world during the years preceding 1940 were in the areas of relativity and quantum theory. Since the Second World War, they have come rather in biochemistry and its related disciplines; and, as a result, we now have a picture of the sub-cellular processes that underlie genetics and heredity far clearer and more detailed than could be foreseen in 1945. Indeed, the basic “geography” of the living cell is by now so well mapped that we can begin looking further ahead to the virgin lands of the next intellectual frontier. Thus C. H. Waddington concluded a recent survey of New Patterns in Genetics and Development (originally delivered as the Jesup Lectures at Columbia University) with the hope that we might.
…see the present fashion for molecular genetics diluted by the diversion of rather more attention to fundamental embryology. Genetics has had its breakthrough, and those who want quick results can probably get them most easily by exploiting this. But the next breakthrough we need, to round off our understanding of fundamental biological processes, is an embryological breakthrough. Let us hope we get it soon.
A similar change is visible on a broader intellectual plane. When C. P. Snow first delivered his Rede Lecture on The Two Cultures and the Scientific Revolution, his example of a scientific concept which should (as he claimed) be the common property of all educated men was the concept of “entropy”—the key notion involved in the Second Law of Thermodynamics. A decade later, in his reconsideration of the subject, Snow himself confesses that he would set aside entropy in favor of D. N. A. If there is to be any touchstone for recognizing the scientifically aware-humanist, this is now to be found in his acquaintance with molecular biology. Entropy is vieux jeu.
Yet even this is only the beginning of the matter. A generation ago, many fields of human art and experience shared common guiding ideas of space, of layout, and of structure. Today these seem to be giving way to other ideas: ideas such as form, organization, and function. We are moving out of a period of formalism and abstraction—of atonal music, non-representational painting, symbolic logic, and machines à habiter—into a new phase of dynamic sculpture, human ecology, and cybernetics—a phase in which electronic computers simulate the activities of men, and buildings imitate the operations of living organisms. In these terms, indeed, we may legitimately describe Saarinen’s TWA terminal at the New York International Airport as the first truly “biological” building, in which the Euclidean severity of a Park Avenue Bauhaus has softened into the more flexible outlines of an amoeba, complete with tentacles (or pseudopodia) to stretch out to an aircraft and exchange the passengers who form their common nutriment.
So widespread a change of style creates both new markets and new problems. We need not wonder to see the bookshops afloat on a rising tide of works about biological and near-biological topics—ranging all the way from college texts and pieces of frank popularizations, through intellectual manifestos, to serious essays in “natural philosophy.” The task is, rather, to find our way along the rapidly filling shelves, and to judge fairly all the implications which are claimed for biology in the fields of ethics, education, culture, public understanding, mental health, sociology—and even practical politics. Yet the more our lives and ideas come under the influence of biological discoveries and patterns of thought, the more desirable it is that we should come to grips with the science directly, and understand just how much it really implies for us.
Those who merely want to pass the Snow test can be served easily enough. Month by month, up-to-date reports on the doings of D. N. A. and R. N. A. appear in the pages of Scientific American; several recent books—of which J. A. V. Butler’s The Life of the Cell is a worthy example—survey current discoveries on the subcellular plane in terms which presuppose only the ABC of science; while those who are rather further along in the alphabet can tackle F. R. Jevons’s more technical exploration of The Biochemical Approach to Life. Above all, readers who are looking for an introduction to contemporary biological thought which is at once reliable, balanced, elementary and humane can go straight out and buy C. H. Waddington’s lectures on The Nature of Life. In an age of scientific specialists, Waddington takes care never to lose himself in a preoccupation with some one aspect of the living organism—whether the lightning, sub-microscopic changes in its biochemical economy, or the million-year trends by which older species give way to new. Instead, he has always cultivated a sense of proportion, and remembered that every biological change has to be studied against four quite different time-scales. The first of these scales (marked in seconds and minutes) measures the activities of genes and chromosomes, and the changes going on inside single cells; the second (marked in hours and days) measures the working of complete cells and organs, in health and disease; the third (marked in months and years) is the man-sized scale, on which we can map the birth, growth and aging of individual living creatures; while the final, evolutionary scale, measuring the slow changes in natural species, is marked out in millennia and thousands of millennia. These scales overlap, and the processes they measure interlock. Each evolutionary change (for instance) leaves its mark in the changes going on at all other levels, down to the very types of D. N. A. to be found in the genes of the organisms in question. And biologists—as Waddington sees, and insists—can rest content only when they have unraveled in detail the processes by which biochemical, organic, developmental and evolutionary changes interweave and relate to one another.
In general terms, most biologists would agree, that this was their longterm goal. Yet, from the books which I have mentioned so far, one Socratic lesson stands out clearly. Recent discoveries about the genetic roles of D. N. A. and R. N. A. are, it seems, only the very first steps towards biological wisdom: in the present stage, the more biologists find out, the more they recognize their own ignorance. Thus Butler, when he tackles questions about development and differentiation, can find material to fill little more than four pages, and much of what he does include is taken up with confessions of uncertainty—“It has been suggested that differentiation is brought about by means of chemical substances called organizers but very little is known about such factors…Little is known either of how the genes exert their influence on form, or how growth of different parts is controlled.” Waddington, in his Jesup Lectures, is equally candid: “The fact that a certain gene-substitution in Drosophila causes the appearance of a four-segmented leg in place of a five-segmented one should be regarded as facing us with a problem and not as providing us with an explanation.” In our understanding of the connection between the development of fully formed organs, and the genes which supposedly “control” this development, we are about as far on as a child who has discovered that a dime in the slot of a vending-machine is followed by a cup of orange soda.
After all, then, Snow’s new biochemical touchstone of scientific literacy may well prove as modish and transitory as his earlier, thermodynamic one. The aspects of biology which touch inescapably on our attitudes to life and public affairs—on our politics and philosophy, our ethical and religious beliefs—elude the grasp of the molecular biologist, and have little directly to do with the fashionable nucleic acids. They begin to show themselves, rather, on the intermediate, man-sized scale. For it is there that we are concerned with the biological phenomena which affect the actual quality of human life. Health and disease, character and temperament, social, racial, and blood-groups, a propensity to crime, to musicianship, to obesity—all these have a physiological as well as a social basis, and we have something to learn about them from the biologists.
Something, but not everything; for, in this area of debate, the most necessary things are a clear head and a sense of relevance. The chains of causes and processes leading from a molecular reshuffle in the gonads of a fruitfly to the growth of an abnormal leg may still be mysterious but, barring accidents, their outcome is unambiguous. The corresponding chains linking the genes of a human individual or population to (say) virtue or happiness or social harmony are both longer and—one would suppose—more at the mercy of environmental factors. The implications of our genetic heredity may not yet have had their full and rightful effect on our ideas about law, medicine, and public policy, but there is an equal risk of exaggerating the bearing of sub-cellular structure on our everyday lives.
So (I say) one might suppose. But all these qualifications would strike C. D. Darlington, the Professor of Botany at Oxford, as willful and nostalgic refusals to face the facts. He tells how, at the outset of his career, he heard of the discoveries being made by T. H. Morgan’s team at Columbia University about the “linear mapping” of genetic factors along the chromosomes of the sell-nucleus. To those who were making these discoveries, their scientific value was of course apparent: “But to others, like the present writer,…the intensity of this historic moment was intensified. This was something to be appreciated above all common scientific values.” Ever since then, Darlington has seen genetics as the key, not only to an understanding of biological heredity, but also to the problems of morals and politics: “Educated men are by no means ashamed of professing an ignorance of the discoveries which should determine their conduct. They are content to use the ideas of life, heredity and society which have done service since Old Testament times.” This sad condition he sets out to remedy in his new book on Genetics and Man, which is a revised version of an earlier work on The Facts of Life, published in 1953.
In my mind, at any rate, Darlington’s argument provokes alternate admiration and consternation. His book is no flabby piece of popularization, predigested for weak intellects, but a real and forceful piece of advocacy. We cannot reject his conclusions simply because they offend our tastes: he gets us in a corner, and we can talk our way out only by refuting his reasoning, or by producing better counter arguments of our own. Furthermore, his argument is built around an excellent account of the historical development of modern genetics; and it is admirably written, in the direct and forceful style imposed by Darlington’s own direct and forceful line of thought:
It is absurd to pretend that water and vinegar are equal. Water is better for some purposes, vinegar for others. Vinegar is harder to get but easier to do without. So it is with people. For 200 generations the advance of mankind has depended on those genetically diverse groups, whether races or classes, which have been able to practice mutual help and show mutual respect. The future of mankin will depend on the continuance of such abilities and habits; a happy aim which cannot be assisted in the long run by make-believe of equality in the physical, believe of equality in the physical, intellectual and cultural capacities of such groups.
Yet how far is Darlington’s bluff and forthright dismissal of comfortable liberal illusions justified by our biological knowledge? In all his chapters, one can go along with him up to a certain point. Thus, like H. J. Muller in the United States, Darlington puts great emphasis on the “genetic load” of infirmities that we are storing up to plague our descendants. By canceling out the pressures of natural selection which in the past (to use Darwin’s phrase) “preserved the favored races in the struggle for life,” we are inevitably helping the ill-favored—the halt, the blind, and the lame—to survive and reproduce their kind more profusely than hitherto, and in this way we are unquestionably creating a problem for ourselves. Yet no problem can dictate its own solution. So, when we find Darlington arguing that a State-controlled program of eugenics is the only rational way of dealing with current population problems, we can be forgiven for replying that this doesn’t follow and for turning back to the earlier pages to see where the fallacy crept in.
The truth is that Darlington is pleading a case, not presenting a balanced judgment. All’s fair in a good cause; and Darlington has no doubts about the merits of his own variety of Scientific Calvinism. The public, the lawyers, and the sociologists (in his view) do not want to accept “the uncompromising doctrine of genetics,” but they must have the courage to face the truth. If they do so, they will recognize that his radical conservatism is mere common-sense—that the only effective way to cut down crime is to limit the breeding-rate of those with criminal tendencies; that divorce should be based on “incompatibility of genetic properties”; that class-distinctions and speech-snobberies are legitimate techniques for protecting aristocratic genepools from contamination; and that the State must avoid protecting the weak from the just consequences of their own deficiencies:
It was not lack of research which limited English food production during the last war but the genetic unfitness of a large part of the tenant farmers, the legally secured occupiers who were organized to keep better men off the land.
By this point, we can perhaps recognize our whereabouts. We are back In Samuel Butler’s Erewhon, with one difference—that Butler’s liberal paradoxes were based on an infinite extrapolation of Lamarckism, while Darlington’s conservative ones depend on a corresponding exaggeration of Mendelism and Darwinism. Darlington solves our political problems by the straightforward device of identifying all significant social characteristics with genetically determinate properties. Criminals and schizophrenics, Fuegians and New Englanders, musical geniuses and landed gentry, the successful and the jobless: all are what they are, because their genes have made them so; and, once we have seen this, we shall recognize that the true answers to our political problems are, purely and simply, genetic ones.
Yet, the truth (in Lady Bracknell’s Immortal phrase) “is never pure, and rarely simple.” Nor, one might add, can it be made as readable as a half-truth. If the strength of Darlington’s book lies in the questions he compels us to face, we must look elsewhere for balanced answers to these questions. In a new collection of essays on Heredity and the Nature of Man, for example, Dr. Theodosius Dobzhansky of the Rockefeller Institute in New York tackles Darlington’s questions from a much less extreme standpoint. Readers who already know Dobzhansky’s other works—notably, his classic book, Mankind Evolving (1962*—will not find very much new in these particular essays, for they present in a more popular form the careful and fully documented arguments contained in that earlier book. Still, the new collection will carry Dobzhansky’s ideas to a wider audience, and that in itself is an excellent thing. For, while he does nothing to shirk the problems and quandaries that Darlington emphasizes, there is nothing cranky, extreme or one-sided about the positions he has reached after a lifetime’s distinguished work on genetics, evolution, and anthropology. In some ways, one comes away from his writings with a heavier heart, just because of the studied moderation and judgment with which he presents his own tentative conclusions.
Dobzhansky has one supreme merit as compared with Darlington: he recognizes throughout that the dispute between heredity and environment, between nature and nurture, must in practice be resolved by a compromise, and not by dogmatism. The relevant question to ask about any human characteristic is not, “Nature or Nurture?”; but rather, how far, and in what respects, the one or the other is a contributing factor. And he recognizes, quite explicitly, the temptation to which scientists are exposed whenever moral and political questions arise—that of exaggerating the connection between their own scientific preoccupations and the practical problems of individual and social life:
If the solution of a scientific problem can be twisted to fit one’s biases and predilections, the field of science concerned must be in a most unsatisfactory state. But the nature-nurture issue need not remain intractable forever: evidence that will permit evaluation of the relative roles of heredity and environment in human variability can be obtained, and there is no reason why it should be any less conclusive than in, for example, field corn or Drosophila flies.
But this, Dobzhansky adds, is “a goal to be striven for,” not one we are already in a position to reach. The social and political relevance of biology remains an area in which cool judgment, level-headedness and caution are the first essentials. Above all, we do not yet know enough. The next hundred years will transform our understanding of human genetics, human ethology, and the biological foundations of social and individual conduct. When that day comes, C. P. Snow’s intercultural gulf will in all probability abolish itself, and the Science of Man will take its proper place at the center of the Scientific Humanities. Until then, we may read enthusiasts like Darlington for pleasure and stimulus; but for the last words we should turn to the more judicial verdicts of men like Waddington and Dobzhansky.
Theodosius Dobzhansky's Mankind Evolving is available in the Yale Paperbound series at $2.45; and he has written a college text covering much the same ground under the title of Evolution, Genetics and Man (John Wiley & Sons, $2.45). Among Dobzhansky's earlier writings, two can be particularly recommended: his popuular lectures on The Biological Basis of Human Freedom (Columbia Paperbacks, $1.25) and his magisterial discussion of Genetics and the Origin of Species, first published in 1937 and now available in the third, revised edition as a Columbia Paperback at $2.45.↩
Theodosius Dobzhansky’s Mankind Evolving is available in the Yale Paperbound series at $2.45; and he has written a college text covering much the same ground under the title of Evolution, Genetics and Man (John Wiley & Sons, $2.45). Among Dobzhansky’s earlier writings, two can be particularly recommended: his popuular lectures on The Biological Basis of Human Freedom (Columbia Paperbacks, $1.25) and his magisterial discussion of Genetics and the Origin of Species, first published in 1937 and now available in the third, revised edition as a Columbia Paperback at $2.45.↩