I distinguish between Platonic and Aristotelian teleologies. I detail William Paley's Platonic teleological argument for the existence of God from natural design and offer Darwin's theory of natural selection as an antiteleological response. But, since Aristotle's teleology is distinct from Plato's teleology I ask to what extent is Darwin's theory anti-Aristotelian.

Teleology in biology is making headline news in the United States. Conservative Christians are utilizing a teleological argument for the existence of a supremely intelligent designer to justify legislation calling for the teaching of “intelligent design” (ID) in public schools. Teleological arguments of one form or another have been around since antiquity. The contemporary argument from intelligent design varies little from William Paley's argument written in 1802. Both argue that nature exhibits too much complexity to be explained by “mindless” natural forces alone.

What is so remarkable about complex designs? Compare a watch with a stone. According to Paley, watches are complex and stones are not because a watch's functioning depends on its precise arrangement; a stone's does not. Michael Behe, a contemporary advocate of intelligent design, labels the sort of complexity “irreducible complexity”: if you remove any part, the whole structure ceases to function (Behe 1996). The bacterial flagellum, Behe argues, is irreducibly complex. It acts as a tiny propeller spinning at more than 20,000 revolutions per minute.