The moral and ontological arguments

The law written on the heart

Paul says that even Gentiles who never received the written law know right from wrong:

So they show that the work of the law is written on their hearts, their consciences also bearing witness, and their thoughts either accusing or defending them

Romans 2:15

It was written, says John Wesley, "By the same hand which wrote the commandments on the tables of stone" Wesley. The moral argument starts from this experience of conscience. We know that torturing a child for fun would be wrong even if the whole world approved. Values and duties that hold whatever anyone thinks or agrees are called objective. The argument runs: (1) there are objective moral values and duties; (2) their best explanation is a God who is good and personal; (3) so morality points to God. It does not say that unbelievers cannot know or do good: as Paul says, they "do by nature what the law requires" (Romans 2:14). The question is not how we know the good but what it is rooted in.

C. S. Lewis opens the question, in Book 1 of Mere Christianity, from everyday quarrels C. S. Lewis, Mere Christianity. People who quarrel appeal to a standard they expect the other to know, one that everyone knows and no one fully keeps. If it were only a herd instinct, he asks, what tells us which of our instincts to follow? If it were only social convention, we could never say that one society's morality is better than another's. So he takes it as a clue that behind the universe there is something more like a mind, which wants us to behave rightly.

Immanuel Kant took another road Immanuel Kant, Critique of Practical Reason. He held that theoretical reason cannot prove God. But the moral law commands us to seek the highest good, virtue joined with the happiness it deserves. What we ought to do must be possible, yet nature and our own powers cannot secure that union. So, Kant said, practical reason must postulate a God who brings it about: not a theoretical proof, but a faith on which the moral life stands.

Two objections

The first objection is an old question from Plato's Euthyphro: is the holy loved by the gods because it is holy, or is it holy because they love it Plato, Euthyphro 10a? Today it is asked of God: is something good because God commands it, or does he command it because it is good? If the first, goodness is arbitrary, and cruelty would be good if God commanded it; if the second, goodness is a standard outside God, and morality seems not to need him. The classical answer takes a third way: the good is neither outside God nor arbitrary, but God's own good nature, from which his commands flow. "No one is good except God alone," Jesus said (Mark 10:18). Critics reply that this only moves the question back a step; defenders answer that every explanation stops somewhere, and the argument's point is that this one stops in a person who is goodness itself. The question is taken further in Who decides right and wrong?

The second objection is that morality evolved. Many scientists accept that cooperation helped our ancestors survive, so that we came to love fairness and hate betrayal; then morality may be no objective fact, only a feeling that once helped us survive. Defenders reply first that how a moral sense arose is a different question from whether what it tells us is true: our ability to count also helped our ancestors survive, yet two and two make four. And if evolution explains all our moral beliefs whatever their truth, it shakes the confidence of anyone who holds that morality is objective without God. Many philosophers who do not believe in God do hold that moral truths are objective, as final facts that need no further explanation; so the argument asks which explanation is better.

Than which nothing greater can be conceived

The ontological argument starts not from the world or from conscience but from the idea of God. How Anselm came to it in prayer, in his Proslogion, is told in The Middle Ages and the Reformation; here we look at the argument itself. (1) God is that than which nothing greater can be conceived. (2) Even the fool who says in his heart that there is no God (Psalm 14:1) understands these words, so God exists at least in the understanding. (3) To exist in reality as well is greater than to exist in the understanding alone. (4) So if God existed only in the understanding, something greater could be conceived, which is a contradiction. (5) So God exists in reality. In Anselm's words, "that, than which nothing greater can be conceived, cannot exist in the understanding alone" Proslogion 2. In chapter 3 he goes further: this being exists so truly "that it cannot even be conceived not to exist" Proslogion 3.

Gaunilo, a monk of Anselm's day, answered on behalf of the fool: by this reasoning an island more excellent than all others would exist merely by being conceived. Anselm replied that the argument fits only that than which nothing greater can be conceived, not islands; later defenders add that an island has no greatest possible form, since a better one can always be imagined. Not every Christian has accepted the argument. Thomas Aquinas held that even if everyone understood the word God so, "it does not therefore follow that he understands that what the word signifies exists actually, but only that it exists mentally" Summa I.2.1; so he argued instead from effects to their cause (the previous lesson). Kant, aiming chiefly at the form Descartes revived, objected that existence adds nothing to the concept of a thing: a hundred real thalers, the coins of his day, are not one coin more than a hundred possible ones. Defenders reply that Anselm's chapter 3 concerns not one property among others but existence that cannot fail, necessary existence. In the twentieth century Alvin Plantinga restated the argument in the logic of possibility and necessity, and philosophers still argue over it.

What they show

If the moral argument succeeds, it points to a holy and personal ground of the good who lays duties on us; if the ontological argument succeeds, to the greatest conceivable being, who cannot fail to exist. Neither by itself reaches the Trinity or the cross. The moral argument leaves heavy news instead: we know the law and have broken it, for "all have sinned and fall short of the glory of God" (Romans 3:23). Lewis held that it is just here that the gospel begins to sound like good news. The ontological argument, born in prayer, has also been read less as a tool for persuading sceptics than as a meditation on God as the greatest, not one being among others.

The roads of apologetics use these arguments in their own ways. Classical apologetics counts the moral argument among its arguments for God; presuppositional apologetics argues that morality makes sense only if the God of Scripture is presupposed; the cumulative case weaves it in among other threads. Evidential apologetics puts historical evidence such as the resurrection first, and Reformed epistemology holds that in experiences such as guilt or gratitude belief in God can arise rightly without argument.

In conversation, never use the moral argument to condemn. A friend who does not believe in God may be honest and kind, and Scripture says so. The question is not whether he is good but what the justice and love he believes in are rooted in. If he is angry at injustice, take his anger seriously, and invite him to think with you about where its standard comes from. Whether God exists is the question of Does God exist? The next lesson, What arguments can and cannot do, asks what arguments like these can and cannot do.

Practice