Horn 1 of the dilemma posed by Divine Command Theory argues that "Divine Command Theory is true and therefore right conduct is right because God commands it (or approves of it) and wrong conduct is wrong because God forbids or disapproves of it."
But this proposal leads to 2 problematic implications.
Implication (1) If right conduct is right because God commands it, then God's commands are morally arbitrary.
Implication (2) If right conduct is right because God commands it, then the doctrine of the goodness of God is empty or trivial.
We will first give consideration to implication 1.
If actions are right only because God commands them, then there is nothing to an action being moral other than God commanded it. This implies that God could command anything at all and it would be morally right. If God were to command rape or torture, then these things would become morally right.
If you are tempted to object by saying, "But God would never command rape or torture, you have to answer the question, why not? The answer cannot be, "Because rape and torture are wrong, after all, If Divine Command Theory is true (as you propose) then something is wrong only if God forbids it or disapproves of it and there is nothing actually to immorality besides being forbidden by God.
If Divine Command Theory is true, then God can have no moral reason for command us to do one thing rather than the exact opposite; in other words, God's commands turn out to be morally arbitrary or in other words God's commands are not based on moral reasons. He cannot have a moral reason not to command rape and torture and this is because those things are not moral or immoral unless he commands or forbids them.
Yes, God might have some other non-moral reason not to command those things. For example, his reason might be that he knows that doing such things will ultimately make most of us unhappy and he wants us to be happy. But if God were very different, e.g. were he not to love us, he might command us to do things that were harmful to others and ourselves. Were he to have commanded those things, then those things would have been morally good.
The philosophical problem here is that if Divine Command Theory is true, then no matter what God were to command or approve of that action would be morally good. It is irrelevant to whether God has actually commanded things that make most of us happy in the long run.
