You might think that the following passage appeared in a creationist text like Of Pandas and People. It's certainly very much the same thing that creationists like Duane Gish and the late Henry Morris have been saying for decades:
We agree that very few potential offspring ever survive to reproduce and that populations do change through time, and that therefore natural selection is of critical importance to the evolutionary process. But this Darwinian claim to explain all of evolution is a popular half-truth whose lack of explicative power is compensated for only by the religious ferocity of its rhetoric.
Although random mutations influenced the course of evolution, their influence was mainly by loss, alteration, and refinement. One mutation confers resistance to malaria but also makes happy blood cells into the deficient oxygen carriers of sickle cell anemics. Another converts a gorgeous newborn into a cystic fibrosis patient or a victim of early onset diabetes. One mutation causes a flighty red-eyed fruit fly to fail to take wing. Never, however, did that one mutation make a wing, a fruit, a woody stem, or a claw appear.
Mutations, in summary, tend to induce sickness, death, or deficiencies. No evidence in the vast literature of heredity changes shows unambiguous evidence that random mutation itself, even with geographical isolation of populations, leads to speciation. Then how do new species come into being? How do cauliflowers descend from tiny, wild Mediterranean cabbagelike plants, or pigs from wild boars?
This is not, however, the superstitious ravings of one of those benighted folk at the Institute for Creation Research. This was written by committed evolutionists Lyn Margulis and Dorian Sagan in 2003 (Acquiring Genomes: A Theory of the Origins of the Species, pg. 29, Basic Books, 2003)
In other words, the classical mechanisms of the neo-Darwinian synthesis, genetic mutation and natural selection, in the minds of these writers, just aren't credible as primary engines of evolutionary change.
Evolutionists disagree on the rate of evolution and the mechanisms responsible for it. The only thing they agree on is that it happened, and, even though they don't know how it happened, they're convinced that no non-physical causes were involved. This is very odd. Given the degree of uncertainty about the major elements of the theory, why are evolution's proponents so adamant that naturalistic processes are solely responsible for it? Obviously a metaphysical bias for materialism or physicalism is driving their science, but, if so, on what grounds is pure physicalism preferable as an explanation to a partial physicalism that leaves room for intelligent agency?
