How can we have knowledge about God?
Catholic tradition holds that there are two sources of knowledge of God: reason and revelation. God’s self revelation, as contained in Scripture and Tradition, gives us access to specific Christian and Catholic doctrines such as the Trinity or the sacraments, which are not otherwise available.
It is also possible to know God through reason. This endeavour is often called natural theology. Many natural theologians follow Anselm of Canterbury in holding that God is ‘that which no greater can be conceived’. It is from this belief that many of the classical divine attributes can be derived. God in this sense has to be omnipotent, omniscient, perfectly free, eternal and perfectly good – if he wasn’t, something greater than God would be conceivable. Similarly, the various arguments for the existence of God give us clues about God’s being. If God created the universe, he must be immensely powerful. If he designed it, he must be intelligent and personal.