In ["The Funeral of a Great Myth," Lewis] distinguished between "the doctrine of Evolution as held by practising biologists," which he deemed to be "a genuine scientific hypothesis," and the speculative versions of evolution that preceded [and it seems followed, with neo-Darwinism]
Charles Darwin's Origin of Species
. Scientific evolution, he argued, is a purely biological theorem. It takes over organic life on this planet as a going concern and tries to explain certain changes within that field. It makes no cosmic statements, no metaphysical statements, no eschatological statements. [my bolds]
Note that by saying evolution theory takes over a "going concern," Lewis acknowledges it is not an origin of life hypothesis. As he notes, evolution theory has nothing to do with metaphysics or theology -- and yet seemingly it has become a "religion" to many of its devotees. Go figure!
Lewis' take on evolution theory seems pretty sound and even-handed to me. Thanks for the ping to this, curiosity.