Anselm
Anselm believed first and reasoned after. His program was three words, *fides quaerens intellectum*, faith seeking understanding: hold the faith, then send reason in to see how much of it reason can reach on its own. The most startling thing it reached was an argument for God that never once looks at the world. From the bare idea of a being than which nothing greater can be conceived, Anselm tried to prove that such a being must actually exist, by thought alone. The argument has been refuted, revived, and refuted again for nine hundred years, and it still will not stay dead. He is the bridge from Augustine's believe-in-order-to-understand to the great reasoning machines of the schools, and the first of those machines that [Aquinas](/philosophy/thinker/aquinas) would build was set running, in part, to take Anselm's proof apart.