above is sufficient to show that what Darwin and his contemporaries took as simple starting points have turned out to be enormously complex—much more complex than Darwin ever envisioned. But how can we tell if the eye and other organisms are too complex to be explained by Darwin’s theory? It turns out that Darwin himself gave us a criterion by which to judge his theory. He wrote in the Origin of Species that: “If it could be demonstrated that any complex organ existed which could not possibly have