Plato holding his Timaeus, detail from the Vatican fresco The School of Athens
According to what I call the "Divine Nature Theory" of axiology or value (hereafter, DNT-A), value is grounded in God's nature. In contrast, moral anti-reductionism (usually called "ethical non-naturalism") says that moral value is grounded in sui generis, non-natural properties.
What is the advantage of DNT-A over moral anti-reductionism? According to DNT-A, God’s nature, not God, is the source of moral value. But what is the distinction between God and His nature? God’s nature is simply the collection of God’s properties or attributes (e.g., omniscience, omnipotence, etc.). But if that is the case, then why do we need God in order for moral value to supervene on one or more of such properties? Or to put the point differently, why must those properties be instantiated in the person of God in order for the supervenience relationship to hold? Why can't they just exist as abstract properties? And if such properties do not need to be instantiated in the person of God, then what is the advantage of the divine nature theory over moral anti-reductionism?