The Moral Argument for the Existence of God

Most arguments for the existence of God, such as the cosmological argument and teleological argument, are from the ancient world. The ontological argument comes from medieval times. But the moral argument is rather modern, emanating from the works of Immanuel Kant (1724-1804).

Kant’s Moral Postulate

Kant strongly rejected traditional arguments for God’s existence. He did not, however, reject belief in God. Rather, he believes that God’s existence is a practically (morally) necessary postulate, even though we cannot prove it.

Kant’s argument from practical reason for God’s existence, from his Critique of Practical Reason, can be stated:

• Happiness is what all human beings desire.
• Morality is the duty of all human beings (what they ought to do).
• The unity of happiness and duty is the greatest good (the summum bonum).
• The summum bonum ought to be sought (since it is the greatest good).
• But the unity of desire and duty (which is the greatest good) is not possible by finite human beings in limited time.
• And the moral necessity of doing something implies the possibility of doing it (ought implies can).
• Therefore, it is morally (i.e., practically) necessary to postulate: (a) a Deity to make this unity possible (i.e., a power to bring them together), and (b) immortality to make this unity achievable.

Kant never offered his postulate as a theoretical proof for God. He did not believe such proof to be possible. Rather, he viewed God’s existence as a morally necessary presupposition, not the result of a rationally necessary argument.

C.S. Lewis’ Moral Argument

The most popular form of the moral argument was given by C.S. Lewis in Mere Christianity. He not only gave the most complete form of the argument in the most persuasive way, but he also answered major objections.

The moral argument of Lewis can be summarized like this:

There must be a universal moral law, or else:

• Moral disagreements would make no sense, as we all assume they do.
• All moral criticisms would be meaningless (e.g., “The Nazis were wrong.”).
• It is unnecessary to keep promises or treaties, as we all assume that it is.
• We would not make excuses for breaking the moral law, as we all do.

But a universal moral law requires a universal Moral Law Giver, since the Source of it:

• Gives moral commands;
• Is interested in our behavior.

Further, this universal Moral Law Giver must be absolutely good. Otherwise, all moral effort would be futile in the long run, since we would be sacrificing our lives for what is not ultimately right. The source of all good must be absolutely good, since the standard of all good must be completely good.

Therefore, there must be an absolutely good Moral Law Giver.

The Moral Law Is Not Herd Instinct.

What we call the moral law cannot be the result of herd instinct or else the stronger impulse would always win, but it does not. We would always act from this instinct rather than selflessly to help someone, as we sometimes do. If the moral law were just herd instinct, then instincts would be always right, but they are not.

The Moral Law Is Not Social Convention.

Neither can the moral law be mere social convention, because not everything learned through society is based on social convention. For example, math and logic are not. The same basic moral laws can be found in virtually every society, past and present.

The Moral Law Differs from Laws of Nature.

The moral law is not to be identified with the laws of nature. Nature’s laws are descriptive (is), not prescriptive (ought) as are moral laws. Factually convenient situation (the way it is) can be morally wrong. Someone who tries to trip me and fails is wrong, but someone who accidentally trips me is not.

The Moral Law Is Not Human Fancy.

Neither can the moral law be mere human fancy, because we cannot get rid of it even when we would like to do so. We did not create it; it is impressed on us from without. If it were fancy, then all value judgments would be meaningless, including such statements as “Hate is wrong” and “Racism is wrong.” But if the moral law is not a description or a merely human prescription, then it must be a moral prescription from a Moral Prescriber beyond us. As Lewis noted, the Moral Law Giver is more like Mind than Nature. He can no more be part of nature than an architect is identical to the building he designs.

Injustice Does Not Disprove a Moral Law Giver.

The main objection to an absolutely perfect Moral Law Giver is the argument from evil or injustice in the world. No serious person can fail to recognize that all the murders, rapes, hatred, and cruelty in the world leave it far short from perfect. But if the world is imperfect, how can there be an absolutely perfect God?

Lewis’ answer is simple: The only way the world could possibly be imperfect is if there is an absolutely perfect standard by which it can be judged to be imperfect. For injustice makes sense only if there is a standard of justice by which something is known to be unjust. And absolute injustice is possible only if there is an absolute standard of justice.

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This Bible class was originally taught by Dr. Justin Imel, Sr., at Church of Christ Deer Park in Deer Park, Texas.