The concept of exaptation is crucial in rebutting the classic biblical argument (now often termed “intelligent design”) against Darwinism, one that dates back to the furor surrounding the publication of On the Origin of Species itself: if extraordinary examples of natural engineering like eyes or wings are not the product of an intelligent creator, then how could these traits have survived through what must have been a pronounced developmental state of nonfunctionality? As the wing evolves, by definition it has to go through a long period where it’s utterly useless at flying.
