Published June 19, 2026
Karl Barth was one of the most formidable critics of natural law theology in the 20th century. He was wrong to reject it, but the danger he identified—the corruption of natural law reasoning into ideological justification for racial hierarchy—was real. It’s real again now, as recent social media eruptions make plain.
In the 1930s, German Christians used the language of natural order to baptize National Socialism. God was speaking through blood, soil, race, and national destiny, or so they claimed. In this view, what is naturally occurring takes on the force of divine mandate. Barth saw this flattened-out appeal to natural law, which confuses natural for naturalism, for what it was: ideology draped in theological justification. Ironically, arguments of this nature take on an almost Darwinian hue—arguing from natural fact to moral duty (a form of the naturalistic fallacy).
Barth’s prescription was too radical in dispensing with the idea of natural law altogether. But his diagnosis of what could go wrong was justified. A similar mistake was present in Aristotle’s natural law theory, wherein he invoked the category of natural law to classify persons as natural slaves because of a supposedly lower nature. What Aristotle did is what Barth feared would follow from appeals to natural law absent God’s revelation in Scripture—mapping a desirable social outcome onto “nature” in reverse to justify a preferred social paradigm.
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Andrew T. Walker, Ph.D., is a Fellow in the Evangelicals and Civic Life Program at The Ethics and Public Policy Center. He is also the Dean of the School of Theology and Professor of Christian Ethics and Public Theology at The Southern Baptist Theological Seminary in Louisville, Kentucky, and the founding Managing Editor of WORLD Opinions. He co-hosts The Bully Pulpit, a weekly podcast exploring faith, culture, and politics from a conservative Christian perspective.
