QuestionsDoes God exist?The moral law points to a lawgiver
Does God exist?TheismMoral

The moral law points to a lawgiver

The moral argument

C. S. Lewis 1898 · 1963The moral law everyone feels, and reason itself, point towards God.
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What it claims

God exists: his perfectly good nature is the standard of goodness, and his commands make our duties.

Why

Objective moral duties need a real foundation, and neither nature, evolution nor society can provide it.

The same idea through history
Immanuel Kant1788Critique of Practical Reason: God is not proved by theory, but it is "morally necessary" to assume him so that the highest good (virtue rewarded with happiness) is possible. Kant refuses, however, to ground duty in God.
C. S. Lewis1952Mere Christianity, Book I (BBC talks of 1941-1944): everyone knows a moral law they did not invent, and behind that law there is "something" more like a mind than like matter.
Robert Merrihew Adams1979Best-explanation version: being wrong is being contrary to the commands of a loving God; this theory best accounts for right and wrong, hence a reason to believe in God. Developed in Finite and Infinite Goods (1999).
William Lane Craig1997Two-premise form, popularised in his debates of the 1990s-2000s: if God does not exist, there are no objective moral values and duties; but there are; so God exists.
In short

"The moral law points to a lawgiver" is an argument by C. S. Lewis (Lewis, Mere Christianity (1952), Book I; Craig (1997), 1952) on the question "Does God exist?" (answer: theism). Its claim: God exists: his perfectly good nature is the standard of goodness, and his commands make our duties. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P2). AskPhilosophy presents 5 objections, 4 of them with a documented reply, and the original text behind each premise, checked word for word.

Lewis, Mere Christianity (1952), Book I; Craig (1997)
Valid with an implicit premise

When two people quarrel, each tries to show that the other is in the wrong. That is C. S. Lewis's starting point, in talks on British radio during the Second World War: even someone who says right and wrong do not exist protests as soon as he is treated unfairly. So we know a moral law we did not invent. Where does it come from? For Lewis, a law that gives orders points to someone who gives them. William Lane Craig drew from this the form discussed today: if God does not exist, there are no objective moral values and duties (true even if everyone thought otherwise); but there are; so God exists. Here Craig's first premise is split in two, to bring out the hidden idea the whole debate rests on.

P1There are objective moral values and duties: torturing a child for fun is wrong, even if everyone thought otherwise.
P2 · implicit premiseObjective values and duties do not stand on their own: they need a foundation, something real that explains them.
P3Without God, nothing can play that role: nature, evolution and society produce instincts and habits, not duties binding on everyone.
Therefore God exists: his perfectly good nature is the standard of goodness, and his commands make our duties.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P2, the computer finds a world where objective values exist, God does not, and those values simply have no foundation: they are true, full stop, just as many think "2 + 2 = 4" is true without anything making it true. That is exactly Wielenberg's position.
Valid with P2. P2 and P3 together make up Craig's first premise ("if God does not exist, there are no objective values"). P2 is not stated in the short form, but Craig grants it in debate: the objectivity of morality needs "an explanation". The debate turns on three points: P1 (are there really objective values? Mackie, Street), P2 (can a moral fact be basic, without foundation? Wielenberg) and P3 (is God the only possible foundation, and a good one? Euthyphro, Kant).
Analogy. A referee blows the whistle for a foul. The players argue over whether it really was a foul, but nobody says the rule does not exist. And a football rule was written by someone. Lewis thinks the moral law is like a rule of the game none of us wrote: so we must look for its author elsewhere. The opponent replies that some rules were written by nobody, like those of logic.

Objections

5

Each objection is a conversation: click to see who replies and where the debate stands.

Plato (the Euthyphro dilemma) 399 BC · attacks premise 3

Is the good good because God wills it, or does God will it because it is good? In the first case morality becomes arbitrary: God could have commanded cruelty. In the second, goodness exists before God and without him: God is no longer its foundation, and P3 falls. (See the argument "The Euthyphro dilemma".)

Lewis replies
Robert Adams 1979 · Adams's reply: a loving God
The "modified" theory does not say that whatever God commands is right: being wrong is being contrary to the commands of a loving God. A God who commanded cruelty for its own sake would not be loving, so disobeying him would not be wrong.
William Lane Craig 1997 · Craig's reply: goodness is God's nature
The dilemma misses a third way: goodness is neither above God nor invented by him, it is his very nature (loving, just, generous). His commands flow necessarily from that nature, so they are not arbitrary.
See the rest of the debate (2)
J
Jeremy Koons 2012
The dilemma comes back one step higher: are love and justice good because God has them, or does God have them because they are good? If the latter, there is a standard of goodness outside God. If the former, saying "God is good" tells us nothing any more.
William Lane Craig 2015
These qualities are good because God has them. Every moral theory must stop somewhere, at a point that is not explained further; God, the greatest being, worthy of worship, is a good stopping point, like the standard metre bar in Paris for lengths. And saying what his goodness consists in (loving, being just) still makes sense.
The debate goes on (our summary) The debate goes on over this stopping point. For critics, if goodness is "what God is", arbitrariness has not gone away, it has been moved: why God's nature rather than another? For defenders, every theory has a stopping point, and a perfect being is a better one than a list of abstract rules. Wielenberg turns the argument round: if the theist may stop at God, the atheist may stop at basic moral truths (see the next objection).
Erik Wielenberg 2014 · attacks premise 2

One can be a moral realist without God. Some moral truths are necessary and basic: pointless suffering is bad, and that fact need not rest on anything else, neither on God nor on our opinions. The theist too has such basic truths ("God is worthy of worship"): both sides have moral axioms, they simply do not choose the same ones (Robust Ethics, 2014; debate with Craig, 2018).

Lewis replies
William Lane Craig 2018 · Craig's reply (debate, 2018)
Wielenberg says certain natural facts ("this act causes suffering") make moral facts true ("this act is wrong"), without saying how. Comparing this to the link between mind and body does not work: that link we at least know exists, because we experience it. For these godless moral facts, we do not even know that the link exists.
Erik Wielenberg 2018
The theist is in the same boat. In Craig's theory, "God is worthy of worship" is a moral claim with no explanation outside itself. Every moral realist, believer or not, ends up positing at least one brute moral axiom.
John L. Mackie 1977 · attacks premise 1

Objective values would be very strange things, unlike anything else in the universe: facts containing an order in themselves ("do this"), which we would have to know through a special faculty. It is simpler to think they do not exist: our moral judgements do aim at something objective, but they are all mistaken (error theory). Mackie even grants, in 1982, that such values, if they existed, would make God more probable: for him, one more reason to reject P1 rather than the conclusion.

Lewis replies
C. S. Lewis 1952 · Lewis's anticipated reply
Whoever says he does not believe in a real Right and Wrong goes back on it a moment later: he may break his promise, but if you break yours he complains "it's not fair".
William Lane Craig 1997
We perceive moral values as we perceive the physical world. There is no more reason to deny the reality of the one than of the other: rape or the torture of a child are not just frowned upon, they are abominations.
The debate goes on (our summary) Mackie is not troubled by Lewis's point: his error theory predicts precisely that everyone talks and complains as if values were objective; that widespread error is what he describes. The real disagreement is over what is more certain: the evidence that gratuitous cruelty is really wrong (Lewis, Craig) or the idea that nothing "strange" exists in the universe (Mackie). Note: Mackie and Craig agree on one point, objective values would fit well with God.
Sharon Street (the evolutionary explanation) 2006 · attacks premise 1

Natural selection has greatly influenced our value judgements: loving our children, helping those who help us, punishing cheats helped us survive and reproduce. If moral truths are independent of us, it would take incredible luck for evolution to have pushed us towards exactly those truths. Note: this objection does not target theists only. It troubles everyone who believes in objective values, including atheist realists such as Wielenberg. Street concludes that values depend on our attitudes, not that morality disappears.

Lewis replies
C. S. Lewis 1952 · Lewis's anticipated reply (on instinct)
The moral law is not one more instinct: when two instincts fight (helping someone, keeping safe), something in us judges between them and tells us which to follow. What tells you which note on the piano to play louder cannot itself be that note.
William Lane Craig 1997 · Craig's reply (to the biologist Michael Ruse)
Explaining how a belief arose does not show it is false. Evolution at most proves that our perception of values developed gradually, like our perception of the physical world, which is no less real for that.
See the rest of the debate (1)
Sharon Street 2006
Saying evolution made us "perceive" moral truths because perceiving them helped survival is a scientific hypothesis. It loses to a simpler explanation: these judgements were selected because they drove useful behaviour, whether true or not.
The debate goes on (our summary) Craig's reply targeted an older version (Ruse) saying "morality comes from evolution, so it is false": Street does not say that, she says a realist would have to rely on a coincidence. Some theists reply that their position has an advantage here: if God wanted beings able to know the good, there is no coincidence. Critics reply that one must then explain why God would work through such a brutal natural selection. The point is still much debated, and it affects atheist realists as much as theists.
Kant 1788 · attacks premise 3

Kant, who himself gave a moral argument for God, refuses to make God the foundation of duty: obligation rests on the autonomy of reason, that is, on the law reason gives itself. God is postulated only to make the highest good possible, the final match between virtue and happiness. So there would be a foundation of duty without God, and P3 is false.

no reply
We have not yet found a direct reply by Lewis in the texts.
The debate goes on (our summary) The argument's defenders (Adams, Craig) do not follow Kant here: for them, a law reason gives itself cannot truly bind, since its maker could unmake it. Kantians reply that reason does not invent the law at random: it finds it within itself, the same for everyone. Kant still keeps a necessary place for God, but as hope (that good will in the end be rewarded), not as the source of duty.
What today's voices say
Defend it
John LennoxHe says moral concepts like good and evil make the most sense if God exists, and quotes Dostoevsky: if God does not exist, everything is permitted. He calls it 'a very strong moral argument' and credits Nietzsche with seeing that killing God kills morality.
Wesley HuffHe calls it one of his favourites: if there is evil there is a good to compare it to, then a law, and so a lawgiver.
Bishop Robert BarronHe argues that God is the lawgiver behind the objective moral laws we intuit.
Cliffe KnechtleHe says "the evidence of objective morals points to a moral lawgiver".
William Lane CraigHe states his own moral argument: if God does not exist, objective moral values do not exist; they do exist; so God exists.
Frank TurekHe quotes C.S. Lewis: a man does not call a line crooked unless he has an idea of a straight line. He grants that the moral argument alone leads to a moral God, not specifically the Christian one.
Francis CollinsLewis's case for a universal moral law was the argument that most affected him. He still holds it: evolution does not fully explain altruism, 'a scandal to evolutionary biology'. He calls radical altruism (Schindler, Mother Teresa) the strongest sign that evolution alone does not explain us, 'not a proof' but a pointer. He rejects Dawkins's answer that it is a misfiring of altruism.
Mohammed HijabHe asked an atheist how to get from physical matter to objective morality, citing Hume's is-ought problem, and concluded that only God grounds it.
Trent HornHis moral argument: if moral realism is true, then God exists. He adds that moral facts need an eternal immaterial source, and that God best explains intrinsic worth and moral knowledge.
Criticize it
Christopher HitchensHe says there is no way of deriving morality and ethics from the supernatural. In debates: "we know what the right thing is without being told by a celestial dictatorship".
Richard DawkinsHe says morality clearly does not come from scripture, and that we have grown out of the old rules through secular moral philosophy and rational discussion.
Alex O'ConnorSince his 2017 debate with Turek he answers that the argument assumes objective morality, which he rejects; in 2022 he says it "doesn't really have much going for it".
Lawrence KraussHe rejects the claim that we cannot be moral without God, and turns it round: would a divine order make cruelty good?
Peter SingerWe do not need God for morality: when we live socially we build moral codes from our capacity to reason. He points to Parfit's atheist case for objective moral truths.
Bart EhrmanAgainst the moral argument, he says our moral inclinations can be explained without God, by how humans developed. He compares them to a taste for a drink: they feel strong, but this does not prove an objective value.
Matt DillahuntyAgainst the moral argument, he says no one has shown an objective, universal moral law.