Graubard, M. (1935). Evolution and its present status. In M. Graubard, Genetics and the social order (pp. 52-66). New York, NY, US: Tomorrow Publishers.
http://dx.doi.org/10.1037/13304-005
Darwin postulated the theory of evolution, that is, of the origin of new types by descent with modification from previously existing types. Essentially Darwin dealt more with the origin of species and not so much with types in a loose sense. Darwin's theory of evolution was not based on vague speculation, but like all great scientific theories was a bold and brilliant attempt to postulate a mechanism which would unify and coordinate all of the previously mentioned fields of biologic study. At the same time it also tried to replace the bankrupt theory of special creation and its corollary of the immutability of species, and give an intelligent, scientific answer to the question of the origin of all species. It is obvious that in the absence of knowledge of genes and mutations Darwin was bound to be wrong in any attempt at explaining the cause of variations and the nature of such. Instead of discussing his errors or limitations of knowledge we present the mechanism of evolution as constructed on the basis of all information available to date. (PsycINFO Database Record (c) 2016 APA, all rights reserved)