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,…
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