As far back as the Apostle Paul’s famous speech on Mars Hill, Christian thinkers have been contending for the credibility of the faith. Among contemporary evangelicals, the so-called moral argument for God’s existence is one of the most popular. Although the argument comes in a variety of forms, it draws on one central idea: If you’re a moral realist (rather than a moral relativist) who believes in objective good and evil, then, philosophically speaking, those ethical standards have to be anchored in a divine source. In other words, moral order doesn’t make sense without God.

In their new book, The Moral Argument: A History (Oxford University Press), David Baggett, professor of philosophy at Liberty University, and Jerry L. Walls, professor of philosophy at Houston Baptist University, trace the history of these arguments from their ancient roots to contemporary proponents like C. S. Lewis, William Lane Craig, Ravi Zacharias, Tim Keller, and many others.

“The world has moral features to it that are best accounted for by theism,” says Baggett. “What gives moral duties their authority? What gives human beings their essential dignity and inherent worth?” We can only answer these questions, argues Baggett, with direct reference to God’s morally perfect nature and commands.

Christopher Reese spoke with Baggett about the influence of the moral argument and its relevance for both believers and nonbelievers today.

You draw a connection in your book from the moral argument to the life of Fred Rogers. Can you elaborate on that?

I love Fred Rogers, always have. I was in his original demographic when his show went national in 1968, so he’s one of my earliest memories. The remarkable documentary about him a few years ago made me realize that so much of what he did and stood for is at the heart of the moral apologetic enterprise. The dignity he recognized in people, the empathy he cultivated for the suffering, his care for the most vulnerable, his desire to touch both heads and hearts, his unyielding trust in God’s goodness, and his invitation to love one’s neighbor as oneself—in all these ways and others he embodied so much of what moral apologetics at its best is all about.

I’ve gone twice to the Fred Rogers Center in Latrobe, Pennsylvania, to conduct research and been enchanted both times. Especially in our cultural moment, we need more people like Fred to make goodness attractive. I can hardly wait to meet him in heaven.

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As a scholar and teacher, how do you see students and others engage with the moral argument?

It’s probably been most gratifying to see my doctoral students learn to think about the moral argument in both academically rigorous and eminently practical ways. Many of them are pastors, so they bring a practitioner’s heart to their academic pursuits, and many of them have come to see the power of the moral argument in a number of fresh directions.

We often discuss the story of blogger Leah Libresco, who was an atheist until she eventually underwent a radical change of mind and became convinced that God exists. In her case, she came to think that it was her naturalistic assumptions that simply didn’t cohere with the rest of her beliefs, including her strong convictions about virtue ethics. In other words, it was the moral argument that persuaded her.

In your opinion, how persuasive is the moral argument relative to other arguments for God’s existence?

William Lane Craig has said that when he goes to colleges for debates, the moral argument is the one that tends to be the most persuasive among the audience. Similarly, when asked which argument from natural theology is the strongest, Alvin Plantinga says the moral argument.

Nothing much rides on which theistic argument is the most persuasive. The important thing is to see that the moral argument is an important apologetic resource and one that works best, I think, in tandem with other pieces of natural theology and special revelation. A number of factors likely contribute to the persuasive power of the moral argument. It has a disarming simplicity that appeals to the young, potential rigor that can appeal to the seasoned philosopher, and the resources to speak to everyone in between. Of course, no single argument in this arena reasonably can or should be expected to persuade everyone.

Skeptics often explain morality as a product of unguided evolution. What’s your reply?

We need some of the best Christian minds working in this area, because it’s a challenge that many like to pose. I’ve got to be briefer in my response than I’d prefer. “Unguided” is the key word here. Plenty of believers, including many of the best moral apologists, think evolution itself is potentially consistent with an intelligent designer. But it remains unclear to me how the distinctive features of morality—binding moral obligations, inherent human value, moral knowledge, and the like—are even potentially accounted for by evolution alone. That a behavior leads to reproductive success doesn’t make it morally binding, and it doesn’t invest it with an authoritative and prescriptive force. To think otherwise is to confuse moral and nonmoral goods, it seems to me.

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Among the many proponents of the moral argument that you survey in the book, whose version do you think is the strongest?

That’s tough. I think each one has something to offer, all of them have their strengths, and their cumulative force is remarkable. Setting aside contemporaries, it’s hard for me to decide between the work of John Henry Newman and A. E. Taylor. Both wrote bona fide classics in the area: Newman’s Grammar of Assent and Taylor’s Faith of a Moralist. More Christians today need to rediscover and delve back into these great treasures, and our hope is that this history book would encourage them to do so.

Taylor’s work is brilliantly labyrinthine and can’t be done justice in an interview, but he recognized that who we are as people needs radical transformation, even transfiguration, and we can’t, as he put it, “pull ourselves up by our own hair” to enjoy the sort of goodness that we intuitively seek. He argued that the intrinsic features of moral guilt point in the direction of a personal and perfectly loving God as our first and final cause. He also recognized the role that great literature and a vivid imagination play in a properly expansive quest for truth.

What was C. S. Lewis’s distinct contribution to the moral argument?

Lewis gave perhaps the best-known popular version of the moral argument, most notably at the beginning of Mere Christianity. It came initially in the form of radio broadcasts during the Second World War, just as William Sorley gave his Gifford lectures on the moral argument in the throes of the First World War. It’s worth noting that Sorley talked about the loss of his son in that war. What both Lewis and Sorley show is that the moral argument is far from simplistic or Pollyannaish but rather can be talked about with credibility during the most trying of times.

That Lewis chose to begin his book about mere Christianity with the topic of morality says a great deal about his own convictions and abilities and also the power of the moral argument itself. Of course, Lewis’s version starts with a real, objective moral law to which we’re accountable and the invariable ways we fall short of that standard. We devote a chapter to him in the book, but there are a dozen chapters that come before him. The history of the argument is far richer than many realize. Lewis was standing on a lot of shoulders.

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You praise some thinkers for how they interacted with their ideological opponents. What can we learn from their approach?

In my research, it was delightful to discover that the history of the moral argument, with few exceptions, included thinkers who were remarkably respectful toward their interlocutors. And in some cases, it was in the context of genuine friendship with ideological foes that some of the best work was done.

Newman, for example—who was notorious at times for his biting polemicism—carried on a lifelong correspondence with his “dear friend” William Froude, with whom he failed to see eye to eye. But the correspondence yielded great fruit. Despite their differences, perhaps because of them, the dialogue really was a kind of “iron sharpening iron.” In these divisive times, Newman provides a refreshing reminder that outreach, apologetics, and evangelism should feature love, kindness, and even friendship.

What answer does Christian theism offer to the question “How should I live?” that other worldviews don’t?

The moral argument has deep existential, pastoral, and devotional insights. It actually has a lot to offer both believers and nonbelievers, largely because it’s not just an argument for God’s existence. It’s also an argument for God’s goodness and love and grace. We recognize a moral standard, realize we fall short, but then discover that the one to whom we’re responsible is also the one who offers forgiveness for falling short and the grace to be transformed into the people we were meant to be. In other words, morality is but a penultimate foretaste of the glory to come.

How has the moral argument influenced or shaped your personal faith?

Well, for a long while now, I’ve felt a personal calling to work in this area, so it’s shaped much of my life and vocation. I was raised in the holiness tradition—which made ethics a natural fit when I discovered philosophy—and then, step by step, I made my way to the moral argument. Each part of the discussion is something that’s for me both intellectually satisfying and fascinating and also deeply devotional. It’s a privilege and joy when our God-given vocations and our spiritual lives go hand in hand, and that’s certainly been true for me. I can’t think of a better way to spend my life than thinking about the perfect and necessary goodness of God.

Christopher Reese is the managing editor of The Worldview Bulletin, co-founder of the Christian Apologetics Alliance, and general editor of Three Views on Christianity and Science (forthcoming from Zondervan, 2021).

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The Moral Argument: A History
The Moral Argument: A History
Oxford University Press
280 pp., 36.59
Buy The Moral Argument: A History from Amazon