Abstract

Theories postulating saltational evolution are a necessary consequence of essentialism. If one believes in constant types, only the sudden production of a new type can lead to evolutionary change. That such saltations can occur and indeed that their occurrence is a necessity is an old belief. Almost all of the theories of evolution described by H. F. Osborn in his From the Greek s to Darwin were saltational theories, that is, theories of the sudden origin of new kinds. The Darwinian revolution did not end this tradition, which continued to flourish in the writings of Thomas H. Huxley, William Bateson, Hugo De Vries, J. C. Willis, Richard Goldschmidt, and Otto Schindewolf. Traces of this idea can even be found in the writings of some of the punctuationists