Thank you Alex for your thoughtful comments. I think there are rational ways to account for the "feeling" of a Platonic world that includes morality as one of its forms that do not include invoking God. In my recent series on dual aspect monism, some of the mathematical physicists promoting dual aspect monism did so because of their belief in such a Platonic world and which their idea of monism can help explain. A popular example is mathematics. Is math invented by humans, or are the great mathematical truths true regardless of human invention and exist in a realm where they can be discovered. Discovery vs invention is the question. I don't think moral realism can be defended as the only or primary reason to believe in God (although in Mere Christianity C.S. Lewis does make it his primary argument), but I do believe that moral realism as part of the entire universe makes more sense than the alternatives when the entire question of transcendence is taken into account.