Can we know that God exists? This is a question that both non-Christians and Christians ask, and it is a question that Scripture answers affirmatively. Key passages like Romans 1:18-20 indicate that evidence for God’s existence is available to all people — such that non-belief is inexcusable. The evidence for God’s existence can be presented and analyzed as arguments or premises, which provide rational support for a conclusion. There are many arguments for God’s existence, but in this article, I will explain and defend the moral argument for God’s existence:

(1) If there is no God, then there would be no objective moral truths.

(2) But there are objective moral truths.

So, (3) there is a God.

If statements one and two are true, then the conclusion must be true as well. So, to defend this argument, we need to show that statements one and two are true.

The first statement says, “There are objective moral truths.” A subjective truth is dependent on personal opinion or belief. An objective truth is grounded in something outside of the person. “My favorite ice cream flavor is chocolate” is an example of a subjective truth, and it is my personal preference. “Columbia is the capital of South Carolina” is an example of an objective truth. It is a fact about the state of South Carolina, and it would be true even if I sincerely believed that the capital was Charleston.

There are some people who claim that moral truths are subjective truths — moral subjectivism and cultural relativism. Both of these subjectivist views, though, are inadequate accounts of morality.

The moral subjectivist believes that the opinion of the individual makes the moral statement true. People sometimes talk like they are moral subjectivists; you might have heard someone say, “That’s true for you, but not for me.” However, moral subjectivism faces serious problems.

If moral subjectivism were true, then there would never be any grounds for criticism of any moral position. If Sue sincerely believed that Mary could be abused and treated with contempt because of her ethnicity, Sue is morally right, and no one can critique her position. But surely this racism is morally wrong and worthy of censure. Though people talk like moral subjectivists, when we push people on their moral beliefs, most everyone has something that they recognize as objectively wrong, demonstrating that moral subjectivism is a false view of moral truth.

The cultural relativist believes that the consensus opinion of a culture grounds the truth of moral statements. Cultural consensus, for example, dictates that stealing is wrong. This is better than an individual’s personal preference but still an inadequate view of ethics.

Cultural relativism faces its own problems. Consider: How would I decide which culture determines my moral truth? After all, I am a member of several cultures. I am a member of the American culture and a member of South Carolinian culture. I’m confident there are several moral issues where the majority view of Americans is at odds with the majority view of South Carolinians. Since I am a member of both cultures, which one determines my moral truth? The cultural relativist doesn’t have a principled solution to this problem.

Since the subjectivist accounts of morality are false, this gives support for the claim that moral truths are objective. For most people, objective moral truths are obvious. Here is a straightforward example of a moral truth claim: “It is wrong to murder.”

It seems obvious to almost everyone that murder is wrong regardless of personal or cultural opinion. In other words, it is an objective moral truth. In summary, we can conclude that statement two of the moral argument is true.

Now let’s consider the first statement of the argument, “If there is no God, then there would be no objective moral truths.”

What if God did not exist? This world would be the result of matter in motion that by chance, over time, developed into the world we have today. Fundamentally, humans would be highly evolved animals. But animals don’t have moral obligations. We don’t think that a wolf is guilty of wrongdoing when it kills a deer. But what would be different about a man killing another man if we were just highly evolved animals? Further, if God did not exist, the world would not be the result of any purpose or intention. If humans are purposeless results of complicated material processes, then what would ground the objective wrongness of treating humans with contempt, or even physically harming other humans? On the other hand, the existence of God would explain the existence of objective moral truths. If God created humans, then His intentions for humans, and His instructions that communicate those intentions, ground the objective moral truths which govern how we ought to live.

If there were no God, there would be no ground for objective moral truths. Yet, we have already shown that there are objective moral truths. Understanding these two truths, we are led to the conclusion that there must be a God. This argument doesn’t show us everything that we need to know about God — for that, we need God’s special revelation in Scripture. But it does show that we can give an affirmative answer to anyone who asks, “Can I know that there is a God?”

— Ross Parker is dean of the School of Christian Studies at Charleston Southern University.