In The Enlightenment (Harper, Feb.), Oxford University professor Robertson recasts the period as the Age of Emotion.

Enlightenment thinkers like David Hume have been castigated for writing some pretty racist things. How troubled should we be about that aspect of their beliefs?

That is a problem. Hume is in the news because one of his essays has a footnote in which he writes that Black people are “naturally inferior” to other races. He also advised a friend to invest in slave plantations. It’s deplorable, but it’s marginal to his work as a whole; it doesn’t cancel out his achievements as a philosopher and historian. I have always admired Hume and I’m not going to desert him now that he’s in trouble; I regret that the University of Edinburgh, where I studied, recently changed the name of David Hume Tower to 40 George Square. It’s also important that, at the time, he was criticized for his attitudes on race; he wasn’t typical. The Enlighteners by and large were against the slave trade and European colonialism.

People think of the Enlightenment as being about rationality and science, yet you foreground emotions, sentimentality, literature, and the arts. Why?

People use the expression “the Age of Reason,” but the Enlightenment was also “the Age of Emotion,” because it valued sympathy and sensibility. One of its most influential philosophers, Lord Shaftesbury, talks about the human instinct for sociability and fellow feeling, and there was a tremendous growth in sympathy for the sufferings of other people and of animals. That sensibility in large part was responsible for the opposition to the slave trade. People started to ask, “How would you like to be treated as a slave?”

Conservatives have decried the Enlightenment as the vanguard of atheism and revolution. Is that fair?

No. Atheism was rather rare in the Enlightenment. Many Enlighteners were Deists, believing in a good God that created the world but who then left it alone. But in the 18th century, as now, there were conspiracy theories and it was believed widely on the right that the philosophes were trying to undermine society. When the French Revolution broke out, they said, “I told you so! This is the result of a conspiracy got up by the philosophes.”

What makes the Enlightenment relevant today?

One crucial element of the Enlighten-ment is the toleration of different religions. They were coming out of centuries of religious war, which they looked back on with horror—rather as we look back on the Holocaust—with a feeling of “never again.” We need to hold on to that attitude. And really the hallmark of the Enlightenment is empiricism—the conviction that thinking should start from observable facts. That attention to evidence and the questioning of authority are all the more important in the Age of Fake News.