A proof for God’s existence came to Anselm in the dark of early morning, under the solemn sound of psalms, echoing against the stone walls of the church. It was the year 1077, at the monastery of Bec in what is now northern France.
All the other proofs he knew depended on observations about the world: the order of nature and the physics of cause and effect. Anselm, instead, gunned straight for the dream of the Greek philosophers: a God of pure, abstract reason, a secret God of the inner life, which the wise can recognize everywhere they go, sufficient onto itself. Aristotle called it the self-thinking thought.
The proof, which would come to be called the ontological argument, purports to demonstrate the existence of God from ideas alone: the concept of a God that doesn’t exist wouldn’t be much of a God. A true concept of God, “a being than which nothing greater can be conceived,” would have to be a God that exists. Therefore, God exists.
The whole thing dissolved away, along with the sense of certainty. I started to remember the echo of Kant’s devastating complaint against Anselm: existence is not a predicate. God seemed to disappear. But I read on. I was reminded it wasn’t God’s existence that plagued Anselm — of that, he had no doubt — it was the phrasing. Modern arguments and evangelists and New Atheists have duped us into thinking that the interesting question is whether God exists; no, what mattered for Anselm was how we think about God and about one another.I think this last point is central: for a 12th century monk, of course, existence of God is really not in question. A 21st century frame (heck - or even a 17th/18th century frame) thus looses some of the original meaning and the purpose of the argument (by the way, there were critiques of Anselm's argument even during his own life time - so don't think that all of his contemporaries - also believers in God - were simply blown away by his logic).
Read the full article here. By the way, if you want to learn more about the Ontological argument, check out the link in this earlier post: God and Philosophers I: The Ontological Argument.