History of evolutionism – classical Darwinist period
Just as, in his work, Darwin admitted the importance of a number of independent evolutionary mechanisms acting on organisms together with natural selection, a similar plurality approach to the theory of evolution was prevalent in the entire professional community (Gould 2002). Amongst the non-biological public, Darwinism was almost universally identified with his theory of natural selection. This theory was attractive for a large part of society, because it agreed well with the general experience of the inhabitants of England and the rest of the developed world with the functioning of human society in the period of emerging capitalism. Competition amongst individual entities and the success and preservation of the strongest and best adapted to the prevailing conditions was generally recognized as a motor for social change and social, of course primarily material, progress. In contrast, professionals were frequently aware that Darwin’s theory of natural selection has a number of obstacles and that some of the conclusions following from this theory were even contradictory to the then-known empirical facts. For these reasons and also because of the absence of centralized supranational science, a great many various concepts of the theory of evolution, based on a number of fundamentally different mechanisms, coexisted for a period of at least 60 years. Various autogenetic concepts, which assumed that living organisms are characterized by a certain internal tendency towards gradual directed development (Galton, Chambers, von Nägeli, Eimer, Osborn) and frequently even towards gradual perfection (Teilhard de Chardin) always held a very strong position. Other theories assumed that Lamarckian mechanisms of strengthening of highly utilized structures and inheritance of acquired traits are of great importance in the evolution of adaptive structures and in mutual divergence of individual species of organisms (partially also supported by Darwin himself). Some theories considered the direct effect of environmental factors on the properties of organisms (St. Hilaire). Others assumed a fundamental effect of sudden jump-like changes in the properties of organisms (Bateson, de Vries, Goldschmidt, Schindelwolf). Of course, theories assuming the fundamental effect of natural selection also maintained a strong position (Wallace, Weismann).