<human>:  Who came up with the famous philosophical argument called ‘The Ontological Argument’?
<bot>: The Ontological Argument was first proposed by St. Anselm in the 11th century. It goes like this: 1. God exists. 2. If God exists, then God is omnipotent. 3. If God is omnipotent, then God can create a rock so heavy that he cannot lift it. 4. If God can create a rock so heavy that he cannot lift it, then God exists. 5. Therefore, God exists.