Famously, Charles Darwin wrote in The Origin of the Species:
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.
Many proponents of the Flying Spaghetti Monster in the Sky have used this pronouncement to suggest that even Darwin was not fully committed to the preposterous idea of evolution, but if the creationists had read a little further, Darwin continues:
Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound.
It strikes me that the operative word here is “reason.” In the non-debate between science and religion, science relies on reason and intelligence whereas religion doesn’t.
A Celebration of Reading 