When Christians offer arguments for the existence of God based on the beginning of the universe or the objective nature of morality, some atheists will respond by asking, “Why can’t we just say we don’t know what caused the universe or what the objective source of morality is?” How might a thoughtful Christian respond?

I would suggest that you turn the question around. Ask them, “Why can’t we just admit that God best explains the origin of the universe and the objective nature of morality?” The atheist wants to plead ignorance, but we are not ignorant on these matters. It’s not as if we don’t know what the options are. We do. And it’s not as if the evidence is equal for all options. We have solid scientific, philosophical, and logical evidence that points to God as the cause of the universe and ground of morality. In other words, we have knowledge, not ignorance. So why not just say we don’t know? It’s because that would be a false statement. We do know. The evidence clearly favors the theistic hypothesis.

The atheist wants to plead ignorance, not because we don’t know of any possible explanations or because the evidence for any of them is equal, but precisely because we know the options and the evidence overwhelmingly points in the direction of the theistic explanation. That puts him in a pickle. He doesn’t like that conclusion, but he can’t refute the evidence for it either. If he admits that he rejects the existence of God for volitional or emotional reasons rather than rational reasons, he knows he would look foolish. So instead, he claims he’s just comfortable admitting that we don’t know the answers yet.

In saying so, he implies that he believes (1) the answer will be found in the future and the answer will not involve God, and (2) that the reason you adopt a theistic explanation is because, unlike him, you cannot tolerate uncertainty and ignorance. Not only does his response dodge the evidence presented to him for God’s existence, but it also proclaims his intellectual superiority over you as well. Don’t fall for this trick. It’s a red herring. Steer the conversation back to the evidence. Make it clear that the issue is not about one’s ability to handle uncertainty, but about the evidence we have right now that clearly favors one explanation over all others. At the very least, we should adopt the God hypothesis unless and until new evidence might arise that would call this conclusion into question. That’s intellectual honesty and intellectual integrity.