Anselm of Canterbury (circa 1033-1109), also called of Aosta for his birthplace, and of Bec for his home monastery, was a Benedictine monk, a philosopher, and a prelate of the church who held the office of Archbishop of Canterbury from 1093 to 1109. Called the founder of scholasticism, he is famous as the originator of the ontological argument for the existence of God. Anselm was proclaimed a Doctor of the Church in 1720 by Pope Clement XI.
Although utterly convinced of the truth of Christianity, Anselm of Canterbury struggled to make sense of his religion. He considered the doctrines of faith an invitation to question, to think, and to learn, and he devoted his life to confronting and understanding the most elusive aspects of Christianity. In Monologium, his writings on matters such as free will, the nature of truth, and the existence of God make Anselm one of the greatest theologians and philosophers in history.
In Why God Became Man, Anselm tries to answer the question of the incarnation of God in the form of Jesus Christ, concluding that neither men nor God owed anything to the Devil, and that our only debt was to God. Christ died in our place because there was no way we could pay the debt ourselves. Anselm’s theory is highly popular, though not the only one—Abelard, for example, violently disagreed. It is called “Penal substitution” because Christ was substituted in our place and paid our penalty. Anselm was equally radical in his emphasis on human reason. You will notice that this writing is unusual in not containing a single Scripture reference.
The ontological argument was proposed by Anselm of Canterbury in the second and third chapter of his Proslogion. Anselm's basic argument in Chapter 2 of the Proslogion goes as follows. First, when we hear the words "than which nothing greater can be thought," we understand what the words convey. Secondly, we are able to understand that what exists does so in at least the form of a thought. At this point it must be conceded that what exists does so either only as a thought or as both a thought and reality. However, it must be conceded that such a concept cannot exist only in our thoughts simply because if it existed only in our thoughts, then we could think of something greater than it: that which exists not only in thought, but also in reality - a conclusion which is logically forbidden by the initial premise (since to do so implies the contradiction of thinking of something greater than that which nothing greater can be thought.) It is at this point that the existence of the very thing which nothing greater can be thought cannot be confined to simply an intellectual existence, but must be endowed with a greatness that supersedes mere intellectual existence so as to also enter into and permeate all of objective, ontological existence. In conclusion, that which nothing greater can be thought truly does exist, and in later chapters of the Proslogion Anselm argues that this being has the traditional attributes of God like being the omnipotent creator.
Anselm’s argument was controversial even in its time, leading other critics to attempt to debate his ontological argument, as well as some of the greatest thinkers in history over the centuries.
