Anselm's Ontological Argument and the Philosophers Saint Anselm of Aosta, Bec, and Canterbury, perhaps during a moment of enlightenment or starvation-induced hallucination, succeeded in formulating an argument for God's existence which has been debated for almost a thousand years. It shows no sign of going away soon. It is an argument based solely on reason, distinguishing it from other arguments for the existence of God such as cosmological or teleological arguments. These latter arguments respectively depend on the world's causes or design, and thus may weaken as new scientific advances are made (such as Darwin's theory of evolution). We can be sure that no s