Anatomy of a quote mine:
@Meerkat_SK5 quotes, though he does so at third or fourth hand and has no idea of the actual source or even the author’s name, from George Gaylord Simpson. 1945. The Principles of Classification and the Classification of Mammals. Bulletin of the American Museum of Natural History 85:i-xvi, 1-350.
The quoted part consists of pieces of two paragraphs (in italics below), separated by a long and unmarked ellipsis. The final sentence of the quote-mine, with a marked ellipsis, does not appear at all in the original publication.
The change in the assumed basis of classification came with general acceptance of the theory of evolution. The belief that different animals, even very unlike animals, were actual flesh-and-blood relatives and had common ancestors suggested that it would be more natural, or philosophically preferable, to define groups by community of origin. This radical change, much the most revolutionary in the whole history of taxonomy, had extraordinarily little immediate effect on the general nature and aspect of formal classifications. From their classifications alone, it is practically impossible to tell whether zoologists of the middle decades of the nineteenth century were evolutionists or not , and classifications intended to be phylogenetic differed as much among themselves as they did from frankly archetypal classifications.
This was partly because the superficial aspects of classification do not necessarily change when the underlying meaning changes — we still use the Linnaean hierarchy and nomenclature (in essentials), although we have rearranged and multiplied his categories and give them a totally different significance. More particularly, in this transition period and, in decreasing extent, almost up to the present, the reason for so little evident change in classification was that the evolutionists and non-evolutionists followed the same procedures. The evolutionists continued to group animals by the number and kind of characters that they have in common, but they explained the possession of these characters by community of inheritance, while the nonevolutionists explained them by a subjective pattern. By substituting “common ancestor” for “archetype” the same classification could be considered phylogenetic or not, at will. The common ancestor was at first, and in most cases, just as hypothetical as the archetype, and the methods of inference were much the same for both, so that classification continued to develop with no immediate evidence of the revolution in principles .