Darwinism in their hands really amounts to a counter-metaphysics planted like a foreign body in the heart of biology. The Pope would have clarified matters greatly if he had repeated the observation of Catholic thinkers like Gilson that the real debate is not over evolution per se, but teleology. Either life forms came about by blind chance or they did not. Darwin's theory is the only one available which purports to explain how Homo sapiens and other species are exclusively the result of natural forces. There are no other theories available which do not smack of vitalism, than which there is no dirtier word in the lexicon of Darwinists.
Evolution actually has an ancient Catholic pedigree.
St. Augustine was an evolutionist, although hardly a Darwinist. This is evolution in the strict etymological sense of the word, an unfolding of what is already there, like an acorn turning into an oak. At the time of the Scopes trail, Chesterton remarked that Catholics were not at all involved in a battle which set biblical and scientific fundamentalists against one another. As usual, there was a reasonable Catholic center which allowed both science and theology their due competence. This would have involved the direct intervention of God, who creates each rational soul out of nothing.