The moral argument — where does right and wrong come from?

This is the argument most likely to reach a real person in a real conversation, because it does not require any physics and it engages something they already believe without noticing.

1. If God does not exist, objective moral values and duties do not exist. 2. Objective moral values and duties do exist. 3. Therefore God exists.

Clear the misunderstanding first

Every time, before anything else.

The argument is not that atheists cannot be moral. They obviously can, and often are more scrupulous than believers. Christians should say this plainly and mean it.

It is not that you need to believe in God to know right from wrong. Scripture says the opposite: Gentiles who do not have the law "show that the work of the law is written on their hearts" (Romans 2:15). Moral knowledge is universal, precisely because everyone bears God's image.

It is a question about grounding, not about behaviour. Not can you recognise the good? but what makes anything good? Not epistemology — how we know — but ontology — what makes it so.

Fail to make this distinction and your interlocutor will hear an insult and stop listening, correctly.

Premise 1: without God, no objective morality

The point is that a purely material universe has no resources for obligation.

If everything that exists is matter in motion governed by physical law, then "you ought not to torture children" is a claim of a very strange kind. It is not a description of any physical fact. It cannot be measured. So what makes it true?

Notably, several prominent atheists concede this.

Richard Dawkins: a universe of blind physical forces has "no design, no purpose, no evil and no good, nothing but blind pitiless indifference."

Jean-Paul Sartre saw it clearly: if God does not exist, we find no values to legitimise our conduct — everything is permitted, and man is abandoned with nothing to cling to.

Michael Ruse, an atheist philosopher of biology, has written that ethics is an illusion put in place by our genes to make us cooperate, and that morality is "just an aid to survival and reproduction" with any deeper meaning being illusory.

These are not caricatures constructed by apologists. They are atheists thinking the position through.

The is–ought problem

David Hume, himself a sceptic, identified the gap that any naturalistic ethics must cross.

You can describe what is: humans evolved cooperative instincts, most societies prohibit murder, oxytocin promotes bonding. None of that yields what ought to be. Descriptions do not generate obligations.

Evolution can explain why we feel that cruelty is wrong. Feeling that something is wrong and it being wrong are different claims, and the second is the one at issue.

And the theory has particular difficulty with what we most admire. Maximilian Kolbe volunteered to take the place of a stranger in an Auschwitz starvation bunker and died. Selection should ruthlessly eliminate that impulse — it removes the altruist from the gene pool for the benefit of someone carrying none of his genes.

We do not regard Kolbe as a genetic malfunction. We regard him as the finest thing a human being can be. That judgement requires a standard evolution cannot supply.

Premise 2: objective morality exists

Most people will not say this out loud, and almost everyone lives it.

Test it with the hard cases. Was the Holocaust wrong, or merely disfavoured by other cultures? Is torturing children for entertainment wrong, or is it a matter of local preference? Almost nobody, pressed, will say these are only matters of taste.

Note that reformers require it. Wilberforce opposed slavery when his culture endorsed it. If morality is cultural consensus, then he was not right — he was deviant, and the culture had no obligation to listen. Every moral advance in history has depended on someone appealing to a standard above their society.

Watch what happens when someone is wronged. This is the most reliable demonstration. A committed relativist who is defrauded, betrayed or assaulted does not say "how culturally interesting". They say that is not fair — and they mean it objectively, about the person who did it.

Lewis's route into the argument came from the other direction:

My argument against God was that the universe seemed so cruel and unjust. But how had I got this idea of just and unjust? A man does not call a line crooked unless he has some idea of a straight line. What was I comparing this universe with when I called it unjust?— C. S. Lewis, Mere Christianity

The strongest atheist objection — the problem of evil — quietly assumes the premise it needs to deny.

The Euthyphro dilemma

The serious counter-argument, from Plato: is something good because God commands it, or does God command it because it is good?

If the first, morality is arbitrary — God could have commanded cruelty and it would have been good. If the second, there is a standard above God, and God is not the ultimate source.

The answer is that the dilemma is false, because there is a third option.

Goodness is neither above God nor invented by God. It is identical with God's nature. He does not consult an external standard and he does not arbitrarily decree; he is the standard, and his commands are expressions of what he unchangeably is.

So could God have commanded cruelty? No — not because something restrains him, but because it would contradict his own nature. God cannot lie (Titus 1:2) or deny himself (2 Timothy 2:13). This is not a limit on his power; it is what it means to be a being of settled character rather than arbitrary will.

Then turn it around, gently: the dilemma presses much harder on the atheist. If there is no God, and moral facts are supposed to exist independently, where do they live? In what does a non-physical, prescriptive, universally binding obligation consist, in a universe of particles?

Using it in conversation

Ask, and then leave it with them.

What it establishes

A moral lawgiver. Personal, since only persons issue obligations. Good, since he is the standard. Authoritative over all people.

Not yet the Trinity. Not yet the cross. That is the next stage of the case.

But it does something the cosmological arguments cannot. It moves the conversation from abstract cosmology to the person's own life — because everyone has done something they know was wrong, and the argument quietly raises the question of what to do about that.

"He has told you, O man, what is good; and what does the LORD require of you but to do justice, and to love kindness, and to walk humbly with your God?" (Micah 6:8).

The moral law is not finally a philosophical proof. It is a mirror. And once someone has seen themselves in it, they are ready to hear about grace.