What did C.S. Lewis believe about evolution?

Everyone likes a good C.S. Lewis quote to bolster their argument.

On Biologos David Williams has a great series of blog posts Surprised by Jack about C.S. Lewis considering his views on Scripture, Genesis, the Fall, and Evolution. It challenges our views of Lewis [why are conservative evangelicals so infatuated with this Anglo-Catholic?] and examines what he actually believed rather than what we might wish he believed.

Here is an extract of the post about evolution, which first discusses how Lewis overall accepted the science of evolution.

What Lewis did believe to conflict with Christian faith was what he called the great “Myth” of “Evolutionism” or “Developmentalism.” But this is not the same as evolutionary theory per se. “[We] must sharply distinguish between Evolution as a biological theorem and popular Evolutionism or Developmentalism which is certainly a Myth,” he writes in his essay "The Funeral of a Great Myth.” 

Lewis believed that the great myth of “Evolutionism” conflicted not only with the Christian faith, but with Reason itself, undercutting the grounds for believing in human rationality and, therefore, in any human rationale that could be offered for believing in Evolutionism in the first place. According to Lewis, Evolutionism’s chief premise, namely, Naturalism, invalidates human reasoning itself, amounting to “an argument which proved that no argument was sound—a proof that there are no such things as proofs—which is nonsense.” “All possible knowledge…depends on reasoning,” he writes in chapter III of Miracles. “We infer Evolution from fossils: we infer the existence of our own brains from what we find inside the skulls of other creatures like ourselves in the dissecting room.” All sciences, including evolutionary science, depend upon the validity of human inference for their own validity. “Unless human reasoning is valid no science can be true.” Naturalism, however, with its grand Myth of Evolutionism explains all of reality, including human reason, in terms of non-rational natural causes and effects, reducing all human reasoning to being no more than the accidental byproducts of chance, matter and time, and thereby undercutting the validity of reasoning itself.

 This important distinction between evolutionary science and evolutionism [a philosophical perspective] has also been stressed by Tim Keller.