I‘m reading Debating Christian Theism, based on Keith Parsons’s recommendation. I just finished reading the essays by Paul Copan and Louise Antony debating moral arguments for God’s existence. Antony’s essay ends with a very interesting point.
In a way, it’s puzzling why, of all God’s attributes, moral goodness is the one held to be constituted merely by God’s possessing it. God is omniscient, but what’s true is not held to be true in virtue of God’s believing it; God is omnipotent, but something is not a possible power because God possesses it. In both these cases, we allow that something external to God delineates the domain, and the perfection of God’s nature lies in the perfection of the matchup between the two. To say that God approves the good because it is good is not to say that God is “bound by” an external standard any more than saying that God believes only what’s true limits his powers of cognition. A God who approves all and only what is objectively good would be a morally perfect being, just as a God who believes all and only truths would be an epistemically perfect being.