I grew up in Tennessee, where it was against the law to teach the theory of evolution. My teachers spoke of dinosaurs and cavemen, but what they were not allowed to say explicitly I read in library books. I became one of those Christians who did not believe that the theory of evolution was incompatible with religion.
Although I am writing about evolution in the context of atheism, it certainly is possible for religious people to embrace evolution or any other science. It is not possible, on the other hand, for an atheist to embrace creationism. Nor is it possible for any scientifically oriented person. Creationism, now known as Creation Science, is not science. It is religion using the trappings of science to align observed fact with the claims of Genesis.
The creation scientist's answer to evolution is “intelligent design.” This is the old time creationist argument dressed in the jargon of modern science. The human eye was deliberately designed, just as everybody before Darwin believed. Books on intelligent design, written by creationists, avoid referring to the designer as “God” to get around issues of separation of church and state. The designers could be space aliens, for all they are willing to say.
Creation Science rejects the premise that the species of today emerged from accumulated changes in the species of the past through natural selection. They distinguish between micro-evolution and macro-evolution. Micro-evolution does not create new species. The way human populations changed skin color as they moved out of Africa is allowed. Macro-evolution produces one species from another. The evolution of birds from dinosaurs is not allowed.
Ann Coulter, who claims to be a Christian but not a scientist, devoted three chapters of her book Godless to her defense of Creation Science. She understands the word “theory” as a lawyer understands it: as a loose structure of speculations, more or less plausible, that support or discredit the case. There is no place for troublesome discrepancies.
There are plenty of troublesome discrepancies in the theory of evolution, some already resolved, some still outstanding. But evolution accounts for so much that scientists are not tempted to throw it out and plug the gaps with God. Creation Scientists are quick to say “I don't see any way this could have happened, so an intelligent designer (God) must have done it.”
This is the argument from personal incredulity. They quote Darwin: “To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.” But they don't quote his answer, that the perfect eye can be traced back to simple and imperfect eyes by “numerous gradations . . . each grade being useful to its possessor.”
This is also Darwin's answer to the misconception that evolution claims that we arouse by “pure chance.” Mutations are random; natural selection is not. Only beneficial mutations persist, so that elaborate structures evolve through “numerous gradations . . . each grade being useful to its possessor.” Richard Dawkins, in his Book The Blind Watchmaker, describes how natural selection emulates purposeful design.
My problem with intelligent design is that it attempts to account for the complexity of life forms by something even more complex. Who designed the designer? Remember the song about "The Old lady who swallowed the fly?" She swallowed a succession of larger and larger animals, each to swallow the next smaller creature, from a spider to a horse (She died of course). To me a creationist is someone who went straight from the fly to the horse. I like to believe evolution has made most of us smarter than that poor lady.