Craig's two premises and the conclusion
William Lane Craig has popularized the argument in its cleanest form:
- If God does not exist, objective moral values and duties do not exist.
- Objective moral values and duties do exist.
- Therefore, God exists.
The argument is modus tollens if the premises stand. Premise 2 is the easier sell — most reflective people, including most Muslim friends, agree that gratuitous cruelty (the torture of an innocent for fun) is really wrong, not merely socially distasteful. Premise 1 is where the work happens. The claim is not atheists cannot be moral (they often live morally), but that atheism cannot ground objective moral values — give them ontological status as features of reality rather than products of evolution, sentiment, or social contract.
Romans 2:14-15 — the work of the law written on their hearts — is the biblical anchor. Christians and Muslims share this premise: morality has divine grounding, not human invention.
Euthyphro and the divine-nature response
The classical objection is Euthyphro's dilemma (Plato, c. 399 BC): Is something good because God commands it, or does God command it because it is good? The first horn makes morality arbitrary (God could have commanded torture). The second makes morality independent of God (and so the moral argument fails).
The modern Christian answer — Robert Adams, William Alston, Craig — is to deny the dilemma. Goodness is grounded in God's nature (his eternal character of love, holiness, justice), not in his arbitrary commands. God commands what is good because he himself is good. The dilemma's force depends on treating God's will and God's nature as separable; on classical theism they are not. Muslim philosophers in the muʿtazila tradition wrestled with the same dilemma; modern Christian theology has the more developed answer.
The atheist responses worth knowing are Sharon Street's evolutionary debunking, Erik Wielenberg's non-natural moral realism without God, Hobbesian contractarianism, and J. L. Mackie's error theory. Each pays a different bill — Street's evolutionary view tends toward moral skepticism; Wielenberg posits brute necessities with no clear grounding; contractarianism cannot explain duties to those outside the contract; error theory openly denies that the torture of an innocent is really wrong. Christians grant that smart atheists hold these views; the moral argument asks the unreflective atheist whether he really believes nothing is objectively wrong.
The point of contact with a Muslim friend — and beyond it
Muslims share premise 1 with Christians. Tawḥīd grounds morality in Allah's command. So the moral argument is not the place where Christian-Muslim conversation divides — it is a point of agreement against the secular West and a useful place to stand together briefly before walking on to deeper questions.
The deeper question is whether moral law alone is the gospel. Christians say no. The moral argument shows there is a moral lawgiver. The gospel shows that the moral lawgiver came in person — John 1:14 — to keep the law on our behalf and bear its judgment in our place. A Muslim friend who agrees there is a divine moral law is closer to the gospel than a Western secularist; the Christian invitation is to meet the lawgiver, not just to know the law.
Worked example
The moment
A secular friend at a dinner with your Muslim coworker says, Morality is just evolved feelings. There's no real right or wrong.
What you might say
"Let me push on that gently. If morality is only evolved feelings, then the torture of an innocent isn't really wrong — it just feels wrong to most of us. Do you actually believe that? Most people don't, when they think about it. And here's something interesting — my friend Ahmad and I both think morality has divine grounding. We disagree about a lot of theology, but we agree there's a real moral law and a moral lawgiver behind it. Where do you ground objective moral values without God?"
Why this works
The answer presses premise 2 with a concrete example, names the agreement between Christian and Muslim on the deeper grounding, and turns the conversation toward whether the secular friend can really hold to moral nihilism.
Watch out for
- Claiming atheists cannot live morally. They often live morally; the argument is about ontological grounding, not psychological capacity.
- Dropping the divine-nature response. Without it, Euthyphro's dilemma still bites.
- Forgetting the Muslim friend largely shares the argument. Treat it as a point of contact, not a wedge.