New Paths in Biology
It is now more than a third of a century since research has been carried out, with increasingly profitable results, on the working hypotheses provided by the synthetic theory of evolution. According to the synthetic theory, organic evolution is satisfactorily explained, in principle and in many details, by the mechanisms of heritable variation and natural selection associated with the names of Darwin and Mendel, and integrated by Ronald Fisher. As I shall show below in connection with definite examples, these mechanisms leave no grounds for objections based on either unfamiliarity with genetics and populations studies (still unfortunately prevalent in some quarters, even among biologists), or on mysticism. Some people, unused to the laws of nature, rebel against the application of scientific determinism to problems of biology. They think that prevalent scientific views on evolution smell of “materialism,” existentialism, or Marxism, and they fondly hope, or wishfully think, that they can escape from the horns of such dilemmas through the eloquent but naive writings of Teilhard de Chardin. That charming man found a few fossils and believed in evolution, but this, unaccompanied by proficiency in genetics and ecology, did not make him qualify as a biologist. That he was a mystic is clear to biologists from the fact that, having rejected the explanatory value of adaptation for survival, he fell back on the proposition that if the tiger has flesh-tearing teeth, it is because, during its evolution, it acquired a “carnivorous soul” (une “ame de carnassier”). For all his value as a moralist, he can be allowed no claim whatever to having been a man of science, as Jean Rostand, George Gaylord Simpson, and Sir Peter Medawar have unanswerably, but charitably, shown.
Other people try to take refuge in hypotheses such as “Lamarckism,” which, as I shall show, is definitely disproved. Some long for the introduction of providential guidance into the argument, neglecting the fact that of the estimated 250 million species of plants and animals that have lived on earth, only 1 per cent has survived today, and of these, all too many are threatened with extinction. Such persons must also adapt themselves to the melancholy fact that countless animals expose other animals to the most atrocious suffering as part of their normal behavior. If this is providence, it is diabolical. Now comes another nonconformist, Adolf Portmann, who finds it difficult to accept that evolution is explicable in principle by the mechanism of natural selection working on heritable variation. So there is a confrontation.
IN BRITAIN and in North America, there have been eminent biologists whose work has influenced schools of teaching and research, not only in their own countries, but also, thanks to a common tongue, a shared system of thought, and close personal contacts, in each other’s land. The result has been that, on both sides of the Atlantic, there have long been generally shared points of view in most branches of biology, with respect to accepted principles and programs for further research.
At the same time, a parallel state of affairs obtains in continental Europe, where other eminent biologists have been interested in different problems, studied in different ways (the “Anglo-Saxons” would say, without paying sufficient attention to genetics and genetical ecology), with the result that the emphasis in teaching and research is not focused in the same directions, or in the same moulds, in Europe as in English-speaking countries. In the former it would seem that, in part, they are still fighting the battles that raged around Darwin a century ago over the question of pre-established purpose and design in evolution.
Adolf Portmann, of Basle, Switzerland, is one of the most distinguished continental biologists. In the book under review, New Paths in Biology, there is therefore not only an opportunity but a challenge for British and American biologists to take stock of what one of their foreign colleagues is doing, how he is thinking, and what he conceives to be the paths that biology should tread in future. These proposed new paths are not easy to discern.
In a stimulating opening chapter, the author lays down the principle that we study biology from two angles: that of matter, which, today, means molecular biology; and that of our subjective experience of life. It is well to make this clear at the outset, for throughout the book the subjective approach to the problem, which English-speaking biologists in general do not share, is never far from the author’s thought. The emergence of organisms and their parts from the molecular level he calls the “apparative stage,” which he defines as the world of organs: heart, brain, etc. Here he considers that the evolution of the cell nucleus was a more crucial step than that of the cell, because it allowed for the genetic mechanism of segregation and recombination, the re-shuffling and recombination, of genes (in astronomically high numbers of permutations) from both parents that occurs at the inception of every new generation; on this, as he very rightly says, the evolutionary process must rest. But was not the evolution of the structural pattern and adaptation of the cell itself, which is the basis of individuality and the organismal level of complexity, even more fundamental?
IN A DISCUSSION of Natural Form and Technical Shape, the author criticises the deficiency of what he calls “the technical understanding of organisms,” which, it appears, is the study of the technical efficiency of various functions. What he has in mind are such adaptations as the sonic radar equipment which enables bats to avoid objects when flying in the dark. Too much attention to analysis of this sort, he fears, exposes the biologist to the danger of neglecting the whole organism for the sake of its parts. Electronics and cybernetics have helped biologists to interpret many features of the structure and function of nervous systems, including the human, but, he says, “technical understanding can never provide more than a small glimpse of living reality.” With this we should be prepared to agree; but he goes on to say that this tendency towards technical understanding has had devastating effects on our view of nature, because it leads to concentration on “privileged forms” to the complete neglect of others. To the question, what are “privileged forms,” the answer is: those organisms which by reason of their coloration are particularly glaring or completely inconspicuous. He urges biologists to cease ignoring those forms that neither “strike” nor “deceive,” because there are so many “neutrals,” and to start with these. He gives no specific examples of such neutrals, but leaves the reader to think of the majority of plants and animals that show no obvious or visible adaptations, and neglects the fact, more and more inescapable as research proceeds, that adaptations are no less vital to the survival of the organism for being inconspicuous. As E. B. Ford has shown, whether the underside of a moth’s wings has one or two small spots is correlated with its success or failure in its environment; nobody yet knows why but the fact is there. Why it should be advantageous, in Portmann’s view, to start work on the “neutrals” is not immediately obvious, but Portmann goes on to explain this point and, at the same time, to introduce his philosophy. If, he says, the biologist fails to start with the “neutrals,” we should fail to see that there are so many forms whose significance cannot be reduced to mere functions of preservation. So there it is again, the old stumbling block of the significance to be attached to natural selection. This is now such a threadbare subject that “Anglo-Saxon” biologists should be reminded that generations have grown up who are imperfectly acquainted with the arsenal of new weapons which those who study evolution experimentally (yes, experimentally) now use.
To understand the basis of Portmann’s analysis it is necessary to realize that, while recognizing that selection exists as a process and a factor in evolution, he wants to free biological thinking from its hegemony. But it is legitimate to ask at this point what new path in biology is opened up here. Simply because so-called “privileged forms” show characters that have provided particularly profitable material for experimental analysis which has yielded results that have led to far-reaching general principles, are we invited to believe that such results are in some way invalidated, or restricted in scope? If Portmann would show how “unprivileged forms” can be made the subjects of successful experimental research (for there can be no acceptable “new path in biology” without this), all biologists would be grateful for the opening up of such a path.
THIS ALLEGED IMPERFECTION of the viewpoint of other biologists is, again, intelligible when one realizes that, for Portmann, the preservation of life (to which most biologists would consider that all adaptation tends) is not the paramount aim of organisms. From this he logically deduces that it should not be the paramount aim of organisms, and therefore that it should not be the paramount aim of study by biologists. He concludes that “far from deriding all subjective judgments, the biologist must merely try to understand the restrictive role they may play in all attempts to understand nature.” This injunction is aimed at the biologists who concentrate their attention on forms that “strike” or “deceive”—by which he means animals (and plants) that mimic others, or have warning, threat, or recognition marks, or sensational courtship behavior. But biologists who have specialized in such studies are not likely to be restrained from pursuing their researches on material which has already given them such valuable results and shows every promise of giving them more, nor will they agree that by concentrating on such material they have allowed their “subjective judgments” to blinker them in their understanding of nature.
In a chapter on “The Realm of Images,” Portmann makes a distinction between “outer” and “inner” phenomena, to which he attaches much importance. The former, which he calls “direct,” from their position on the surface of the body, “are directed at the eye of a possible beholder,” e.g., the pattern on the surface of the skin; the latter, which he calls “indirect” are not, e.g., the structure of the liver. This is no doubt true, but what is not clear is the author’s claim that “Our distinction between direct and indirect phenomena may be compared to the psychological distinction between conscious and unconscious processes.” What does this mean? And where is the new path in biology here? It all seems to be related to the distinction which the author made earlier between “privileged forms” that catch the eye, and the remainder that do not; for he is seriously worried by the problem of the origin of external colors and patterns of animals. Other biologists would add the color and patterns of plants to those of animals, but they seem to be less worried.