Selection and Design

Here is one way that philosophers and biologists sometimes speak of Darwin's explanatory innovation: ‘Eyes, organs of echolocation, camouflage and the like are all wonderful instances of contrivance, of complex adaptation, of good design. Paley and the other natural theologians sought to explain this good design by appeal to an intelligent designer. Darwin, on the other hand, offers us a superior explanation for the appearance of this same property: Darwin shows us that we can explain good design through the action of selection. Indeed, selection is the only process that can explain good design in nature. And that is why evolutionary biologists can continue to use a version of the argument from design called the argument from biological design: when we see an instance of good design in nature, we should infer not the guiding hand of God, but the hand of selection at work.’

This way of talking about design and selection raises three interrelated problems. They are the problem of continuity, the problem of monopoly, and the problem of inference. The problem of continuity arises when we ask whether modern evolutionary biology and natural theology both seek to explain the same phenomena. What does this question mean? A very weak reading of continuity is easy to come by, and this reading will yield an affirmative answer to our question. It is true that some of the specific traits that are the objects of natural selection explanations—most obviously traits like eyes and wings—are the same as those that Paley was interested in.