During last night’s prime-time Republican Presidential Candidate Debate, Fox News host Megyn Kelly said this:

after the break, we’re going to let the candidates make their closing statements, their final thoughts, and God. Stay tuned for that.

After the commercial break, Kelly said:

“An interesting closing question from Chase Norton on Facebook, who wants to know this of the candidates: ‘I want to know if any of them have received a word from God on what they should do and take care of first.’ Senator Cruz, start from you. Any word from God?”

This question–and all of the disagreement between the candidates–summed up perfectly the problem that moral apologists for theism often miss: moral disagreement.

Allow me to explain. Theistic apologists who use moral arguments for God’s existence typically use a family of moral argument I’ll call ontological moral arguments. William Lane Craig’s moral argument is a member of this family, as are the argument of Robert M. Adams (arguably), David Baggett, Paul Copan, Doug Geivett, C.S. Lewis, and Jerry Walls.

Many clueless atheist debaters mistakenly bring up moral disagreement as an objection to arguments in this family. Here I have to side with Craig: such debaters are confusing moral epistemology (the order of knowing) with moral ontology (the order of being), so their objection is, strictly speaking, not logically relevant.

It doesn’t follow, however, that moral disagreement is unimportant. After all, what use are ontologically objective moral values and duties (“objective morality”) if we can’t reliably know what they are to settle, much less prevent, moral disagreements? It also doesn’t follow that moral disagreement is irrelevant to theism. While moral disagreement is a weak objection to objective morality, it ‘s rarely noticed that moral disagreement when combined with theism is a strong objection to theism.

The philosophical discipline of ethics is notorious for its controversy. Not only do philosophers disagree over general ethical theory (such as utilitarianism vs. deontological ethics), they also genuinely disagree about the morality of specific acts, like war, abortion, the death penalty, gun control, and sexual behavior.

The problem is not just that people disagree about morality. The problem is also that theists disagree about morality. Now this tends to be very awkward for the theist. A theist, at least if he admits there is genuine ethical disagreement, has to believe both that God wants humans to behave morally and that He has left them in the dark about whether specific kinds of behavior are morally acceptable.

On naturalism, however, there is no God, just impersonal nature. And impersonal nature gives us even less reason to expect moral agreement than theism does. So ethical disagreement is more probable on naturalism than on theism. This is a rarely noticed fact about so-called ‘divine hiddenness.’