What’s the one comparison we’re always itching to make but dare not touch? You might know it as Godwin’s Law. As soon as someone invokes Hitler in debate, all discussion shuts down.

It’s been a few months since I spoke with Alec Ryrie about his remarkable new book, Unbelievers: An Emotional History of Doubt. And I can’t shake his explanation for how secularism in the 20th century displaced Jesus as the standard of Western morality. Ryrie told me:

“We have reached the point where the most potent moral figure in our collective imagination is no longer Jesus, it’s Hitler. We no longer have a figure who teaches us what’s good, but a figure who teaches us what’s evil, and we take our moral bearings from that.

“Fair enough. If you’re going to choose one human being as an embodiment of absolute evil, then I can’t think of a better one, but it has all kinds of consequences. It means that we are orientating ourselves around a secular standard, where we basically just agree to say, ‘Look, Nazism and everything that is associated with it is really bad,’ and we struggle to articulate why. It also means that we now as a culture know what we hate, but we’re not nearly so good at articulating what we love.”

What a timely word for the United States currently engulfed in yet another round of outrage against racial injustice. Ryrie’s work will help you understand how anger and anxiety became the emotional hallmarks of doubt, through a massive transformation effected by World War II until our own day.