That dammed eye─the human eye!
"LUCIEN CUÉNOT, the great French biologist, reserved a central place for his reflections on the eye in his book on finality in biology. If one considers, he wrote, the most specific interconnections involved in the structure of the eye which can be vitiated "by the smallest deviation, the idea of a finalist direction is born invincible.... It is not daring to believe that the eye is made for seeing." These two statements enclose Cuénot's expression of philosophical despair. Its cause is his seeing an irresolvable conflict between the finalist direction, which "amounts to explaining the obscure by the more obscure" and the impossibility "to forgo a guideline in the train of [biological] events." Despair or not, he at least registered the difference between two different perspectives.
"Clearly, as long as a guideline leads somewhere, it means goal-directedness, the very concept which the Darwinian biologist cannot justify on the basis of his method, a method of sheer mechanism. The Darwinian biologist also finds, to continue with Cuénot, "that each type of eye from the most rudimentary to the most developed is complete in itself.... When one examines an animal, one does not hesitate for a moment to identify the eyes." Then the question, "How could one assign to chance variations the recurring origin of such complexes with multiple interconnections?", [Cuénot] becomes an expression of despair about that method. The despair can indeed become so annoying as to make the Darwinian biologist explode: "That dammed eye─the human eye!"[Garrett Hardin]
"Such a reaction makes sense only if it betrays at least a tacit admission on the part of the Darwinian biologist that natural selection is not a wholly satisfactory explanation of the formation of the eye."
~Stanley L. Jaki: The Purpose Of It All, Chap. 3─Pattern Versus Design.