Why should we take God as a moral authority?As far as I can see, we have three choices:
1. We have to prove that he is perfectly good. If, for example, this follows from omnipotency, then all well and good. Unfortunately there seems to be no such argument (and it would also be necessary to prove he really was omnipotent; and to ensure the same meaning for omnipotent is used across both arguments). And anyway, what does perfectly good mean under DCT? How can it be applied to God?
2. We look at God's morality. Of course this is not satisfactory as we cannot judge God's morality if we have none to judge it against.
3. We take his word for it, or someone elses. This is basically taking it on faith. God says he is a moral authority, and we assume he is. Or rather, some priests say he is a moral authority, and we take their word for it. How can we be sure they have not been mislead? How can we be sure they are not misleading us?
I think the usual argument is that God created the universe, therefore morality comes from him, but this is just (3) wrapped up a bit. We are asked to take it on faith that morality comes from God, and that it is a morality that is worth following.
I do not find any of them convincing, but perhaps others do.
No Higher AuthorityAn argument for DCT is that the alternative is to have God subordinate to something.
However, saying that God commands something because it is morally good threatens the sovereignty and independence of God. If an external principle, in this case the objective ground of morality, is outside of God, then God is obligated to adhere to this standard, and thus He is not sovereign. Furthermore, God’s morality depends on His adherence to this external standard; hence his independence is threatened.http://www.gotquestions.org/divine-command-theory.html#ixzz2Xs5qM1vX
If God follows an external morality, then that external morality is greater than him, and that is impossible if we assume nothing is greater than God. And yet most Christians readily admit that God cannot do the logically impossible (see here or here for example), so they are already conceding that God is subordinate to something - the laws of logic.
InterpretationA big problem with DCT is that we do not have clear rules from God. Centuries ago Christians thought slavery was acceptable, nowadays they think it is not. God's commands have not changed, but Christian morality has.
Christians ignore plenty of God's commands, such as eating shellfish and pork, and wearing garments make of two types of thread. They rationalise this saying Jesus was a second covenant, but Jesus was quite clear that his coming did not change those laws. Christianity (starting all the way back with Paul) has just picked out the laws it wants, and decided to ignore those it does not. Commandment number three is to keep the Sabbath. Any Jew will tell you the Sabbath is on Saturday, and that is the day Jesus kept as the Sabbath. Nevertheless, Christians observe Sunday as a holy day, despite God's command.
Really DCT?This verse is of interest when considering Divine Command Theory, when Moses is persuading God not to destroy the Isaelites after they fashion a golden calf and worship it.
Exodus 32:12 Wherefore should the Egyptians speak, and say, For mischief did he bring them out, to slay them in the mountains, and to consume them from the face of the earth? Turn from thy fierce wrath, and repent of this evil against thy people.
Clearly Moses does not believe God is perfectly good nor does he believe in Divine Command Theory, as he says that God's destruction of the Israelites would be evil.
It is also interesting because according to Divine Command Theory, destruction of the Israelites was morally right before Moses spoke up, then became morally wrong after God changed his mind (in both 1 Samuel 24 and 1 Chronicles 21 we see similar changes in what is right and wrong). And this makes a mockery of Divine Command Theory, because how can we possibly know what God currently thinks about murder or slavery or whatever? All we have to go on is a book hopelessly out of date.
What is Right and Wrong?An implication of subscribing to DCT is that a Christian cannot make moral decisions on his own. Whilst most people might look at the consequences of a certain action, might consider whether those involved give informed consent, etc. the Christian who subscribes to DCT does none of that, but instead requires a command from God.
Is it okay to slaughter all the children in a school? Most people would just know that such an action is wrong, but a Christian who subscribes to DCT cannot be sure, not until God has said either way. Of course, in practice, the Christian will assume that God does not want that, which is lucky for the rest of us, but makes a nonsense of DCT. How can the Christian presume to know what God wants? Certainly there is precedent in the Bible for God wanting groups of children slaughtered
2 Kings 2:24 And he turned around, and when he saw them, he cursed them in the name of the Lord. And two she-bears came out of the woods and tore forty-two of the boys.
The only way to know if something is right or wrong is to ask God. And he has been strangely quiet for the last 2000 years.
God is... Mediocre?If God defines right and wrong by his commands, it becomes meaningless to say that God is perfectly good or that God is perfectly just. God has no moral choices under DCT; every option is necessarily good just by virtue of God choosing it. You would not claim a child was brilliant at maths when he always gets 100% on his tests if he does so because his teacher redefine mathematics to make his answers correct. So why consider God to be good?
Why DCT?The reality is, I rather think, that DCT is something that as contrived to rationalise Biblical horrors. Christian morality is pretty much the same as everyone elses. They think about what the consequences of their acyions would be, and if people end up getting hurt, they know that it is wrong. Going into a school and murdering dozens of kids is just wrong - and they know that. Of course they do.
But what about those Biblical atrocities? It is when they look at the Bible that they need DCT. God, they assume, is perfectly good and all-loving, so the slaughter of children in morally right and loving when God does it. They just need to redefine "morally right" and "loving"...
For example, see this:
Second, what about the times when God commands the Israelites to slaughter their enemies down to the very last man, woman and child? Clearly, this is a violation of God’s very own commandment prohibiting murder. The answer is similar to the first objection; namely, God’s nature is the totality of all His attributes. God is good—immutably good—but He is also holy, righteous and just. God is a God who must punish sin and wickedness. The Canaanites were wicked and rebellious and under the just condemnation of God for their sin. We know that the wages of sin is death (Romans 6:23); so God, in His sovereignty, decreed the timing and manner of their death, which was a demonstration of God’s judgment on sin. This, too, is an example of God’s goodness—it is good for God to execute holy judgment on sin.http://www.gotquestions.org/divine-command-theory.html#ixzz2Xs6BYZzJ
Therefore, when God commands certain actions as good and therefore to be done and forbids certain actions as evil and therefore not to be done, it is not simply good because God commands it. It is good because it is reflective of His divine nature.
DCT is ScaryThe problem with DCT is that it can lead to some very screwed up behaviour. If a Christian thinks God has commanded him to slaughter a school full of children then he will think it is morally wrong not to. To me it looks like a short step from DCT to flying aeroplanes into skyscrapers for the Will of Allah. Seriously. The people that did that were religious fundamentalists who had been convinced that what they were doing was the will of God, and so therefore morally right. Divine Command Theory in action.
And I find that scary.