Moral Normativity: Naturalism vs. Theism

It is widely assumed that theism is superior to metaphysical naturalism in explaining moral phenomena, especially with regard to the practical aspect of morality. In this article, I will firstly clarify what this practical aspect amounts to and present two challenges against metaphysical naturalism, by John Mackie and Richard Joyce. Then, I will critically engage with two main attempts to argue for the superiority of theism over metaphysical naturalism: One of them is the appeal to the existence of afterlife, and the other is Robert Merrihew Adams? divine command metaethics. I will argue that both are problematic for different reasons. Relying on the main aspects of Adams? metaethical framework, I will advance my proposal to maintain the practical aspect of morality which lends theism superiority over metaphysical naturalism, and then follow with certain implications of the proposal for theistic metaethics.