Ethics and Theism

In this essay I argue that there are necessarily true synthetic a priori moral propositions whose truth does not depend on the existence of God. To make my case, I appeal to an analogy with arithmetic truths such as 2 + 2 = 4 whose truth does not depend on the existence of God. I criticize views like Peter Railton’s that hold that moral truths are like truths about natural kinds such as water and heat, and non-cognitivists who hold that there are no robust moral truths. The point of my criticisms is to answer challenges to my view that there are necessarily true synthetic a priori moral propositions and, in the case of Railton, to block an argument by Robert Adams for a Divine Command Theory of ethics. Second, I argue by example that there can be conflicts between what is best for me and those for whom I care and what is morally required that cannot be reconciled by a theistic ethics. It can be rational to violate moral requirements that have the same contents as the commands of a loving God even if there would be most reason to adhere to those requirements IF God exists, just as it can be rational to leave your umbrella at home even if there would be most reason to take it IF it rained. This will be true regardless of whether the reason to adhere to God’s commands, IF God exists, is because our greatest good is the love of God (and that requires adhering to his commands) or because God will punish you if you do not and reward you if you do. The problem of evil is the primary reason to believe that God does not exist, and so to believe that there are no divine commands that there would be most reason to follow if God did exist.