The Biological Basis of Human Nature (1930)

The Biological Basis of Human Nature (1930) by H. S. Jennings, Professor of Zoology, Johns Hopkins University

IX. Biological Fallacies and Human Affairs An eagerness to apply biological science to human affairs is a marked feature of the times. Gone are the days when the biologist was best looked upon with amused tolerance; he is astonished to find himself called upon for advice, for leadership. . . . The man in the street recognizes that if his practices are not biologically sound, they are not sound at all; the biological expert must set the seal of his approval upon them. Profound changes in practice are urged upon the world as pronouncements of biological science. This seems the sudden and unexpected realization of a dream long cherished by the biologist. The world, then, is to be operated on scientific principles. The conduct of life and society are to be based, as they should be, on sound biological maxims! Books that lay down these biological maxims are among the best sellers. Biology has become popular! But the enthusiasm of the biologist at this Utopian situation is dampened by doubts and worries as to the soundness of some of the maxims that are circulated in the name of biology. . . . There appear to be a lot of fallacies . . . circulating under the guise of biological principles applicable to human affairs . . . Particularly abundant appear such fallacies in the attempts to apply to human problems, to social reforms, the results of scientific study of heredity. . . .

Our first fallacy springs from the situation just described. It is: I. The fallacy of non-experimental judgments, in matters of heredity and development. This is a fallacy of general method, one of wide distribution, among professional biologists as among other men. It is the fallacy of judging, in these matters of genetics, on any other basis that close adherence to the detailed experimental results; the fallacy of judging propositions in genetics on the basis of one’s general impressions of the rest of the universe; on the basis of what one sees in other fields. . . . Our second fallacy is one that appears in the interpretation of observational and experimental results; it underlies most of the special fallacies seen in genetic biology. This is the fallacy that Morley in his life of Gladstone asserts to be the greatest affliction of politicians; it is indeed a common plague of humanity. It is: II. The fallacy of attributing to one cause what is due to many causes. This fallacy is the commonest error of science, making unsound a considerable proportion of its conclusions. Everywhere there is search of “the” cause of this or that phenomenon; the investigator is not content till he has found “it.” Yet natural phenomena . . . merely arise out of the complex situation in which they occur. Many elements of that situation affect them; and all that experimental science can do is to determine what difference is made by altering one or more of these elements; none is “the” cause to the exclusion of the others. . . . From positive observations that one factor is at work, the conclusion is drawn that others are not; a vicious fallacy. This is our third general fallacy, an immediate child of the second: III. The fallacy of concluding that because one factor plays a role, another does not; the fallacy of drawing negative conclusions from positive observations. This fallacy contributes largely toward making science an entertaining spectacle; from it arise picturesque controversies. What the second investigator finds as “the” cause is not what the first one found; the subject is enlivened by a fight, which human beings love to watch. But if soundness rather than entertainment is the end, then it has to be recognized that any biological phenomenon arises through the interaction of many factors. It does not follow that because one cause has been found, others can be left out of account . . . In biology the two last-stated fallacies appear in many guises. One of the commonest forms, and the most prolific error, is: IV. The fallacy that the characteristics of organisms are divisible into two distinct classes; one due to heredity, the other to environment. This notion is almost universal in the attempts to apply biology to human affairs. It is a form of the fallacy of single causes; a characteristic, it is held, must have as its cause either heredity or environment, as exclusive alternatives. This is a fundamental error, with vicious consequences. All characteristics are products of development, and development is always through an interaction of the “material of inheritance,” the genes, and other things, the environment. . . . V. The fallacy that heredity is a force or entity, set off from the rest of conditions of development, tending to produce resemblance between parents and descendants . . . VI. The fallacy that heredity signifies or requires likeness, of parents and offspring; that it involves the maxim that “like produces like.” . . . In these matters we have striking examples of a general fallacy of thought that plays a large role in science, as in other fields of human activity. It will be worth while parenthetically to formulate it and incorporate is in our catalogue. It is: VII. The fallacy of basing conclusions on implied premises that when explicitly stated are rejected. Many premises influencing reasoning are of this hidden, unconscious type. Such ghostly premises largely affect biological reasoning on the topics here dealt with. . . . VIII. The fallacy that showing a characteristic to be hereditary proves that it is not alterable by the environment. This idea is widespread; one finds it set down as axiomatic even by investigators. . . . The converse fallacy is likewise widely current: IX. The fallacy that showing a characteristic to be altered by the environment proves that it is not hereditary. . . . Among the farther fallacies produced by the interbreeding of those thus far considered, is one popular with certain propagandists of eugenics: X. The fallacy that since all human characteristics are hereditary, heredity is all- important in human affairs, environment therefore unimportant. This notion has been much pushed of late, by near-biologists and to a certain extent by biologists; though happily a reaction from it is in progress. On this basis were to be settled the problems of education, immigration, public health, crime, charity—indeed all the problems of social organization. . . .

[Others] fall into the converse fallacy: XI. The fallacy that since all important human characteristics are environmental, therefore environment is all-important, heredity unimportant, in human affairs. This notion is commonly held for the special field in which one has made personal observations; by medical men for disease; by sociologists for human society and institutions; by psychologists for behavior, for mental characteristics. All these things they find are affected by environmental conditions; hence it is concluded that heredity plays no role in them. The most conspicuous recent example of this procedure is furnished by the Behaviorism of John B. Watson, which sets forth that in normal individuals inheritance plays no part in behavior, in abilities, in aptitudes, in character, in temperament, in what in individual becomes. This is because Watson's studies reveal to him that these matters are deeply affected by environment, education, example, tradition, and the like. . . . [pp. 203-217]

1) What are the author's main points about biology and human beings? 2) How does the author fit into the "Nature" versus "Nurture" debate?