Definition: (1) the explanation of phenomena by the purpose they serve, rather than by postulated causes; (2) the doctrine of design and purpose in the material world
“I said you’ve got to be stone cold dead not to see overwhelming incongruity. It is pointless to search for teleology.”
—“Mediocrity” B-side on Stranger than Fiction
In a sentence: To say that a sex organ’s only purpose is procreation is some pretty selective teleology.
Philosophical significance: Teleological arguments–those which argue for a conclusion based on the purpose (often divine) ascribed to particular mechanism, object, or system–are perhaps most often used in the Philosophy of Religion. Teleological arguments for the existence of God, like Aquinas’, argue that various unconscious aspects of the universe act for some purpose or end, but must have been ascribed this purpose because they lack the intelligence to do so themselves. For example, it may appear that the heart exists to pump blood, but the heart obviously never decided to pump blood. So some theists believe this function was determined by God in the creation of the heart.
William Paley later updated the teleological argument into more modern design arguments. Paley’s Watchmaker thought experiment is a quintessential example of an argument from design (although more recent efforts by Michael Behe, for example, have attempted to integrate biological evidence as well).
Of course, teleological arguments are vulnerable to certain criticisms. For one, it is far from clear that the heart has “purpose” rather than function, and evolution by random mutation and natural selection provides at least one way that things without minds can develop such functions without divine creators.
For more on teleological arguments, check out the Stanford Encyclopedia of Philosophy or ask a philosopher.
sources: the google, TA-ing for the great ken clatterbaugh