What’s the most surprising thing you learned while writing it?
I always knew he was a complete workhorse, just an intellectual beast. But I really didn’t grasp how important he was as a political thinker until I worked on him. He went to Russia to speak with Catherine the Great, who was his benefactor, and tried to democratize the Russian empire. He didn’t get too far.
But later on — and this was discovered only in the 1940s — he was a ghost writer for one of the best sellers of the 18th century, “Philosophical and Political History of the Two Indies,” in which he tackled major subjects that were incredibly influential. He ultimately wrote about 20 or 25 percent of it. He criticized Louis XVI for income inequality. He said France was a powder keg that was going to blow up, nine years before the revolution. And he was also a great antislavery voice, around 1780. What’s remarkable is that he didn’t just say slavery is bad, he refuted all the racial stereotypes in a way no one else was doing at the time. The name of the guy who ostensibly wrote the book was Raynal; he got kicked out of France, whereas Diderot, who wrote the most incendiary parts, got to stay.
In what way is the book you wrote different from the book you set out to write?
The most obvious way of tackling a life is what I call putting a tracer on the person and tracking them from the moment they’re born until they die. I started off that way. But after about a year, I figured out this wasn’t going to work for Diderot because so much of his existence was based on the idea of posterity. He made a huge bet, by putting these things aside, that people like us would ultimately read his unpublished works. One of the most revealing things he wrote was: “One only communicates with force from the bottom of the grave.”
After screwing up a lot of introductions — I have a huge compost pile — I opened the book with the story about grave robbers breaking into the church where he was buried, nine years after his death. They stole lead from his coffin, and tossed him out on to the floor. He had essentially been forgotten by then, while the other two figureheads of the era, Voltaire and Rousseau, had been reburied in the Paris’s Panthéon. But slowly his legacy started to shift. I flipped it and started there. I had to start where I could bring ideas of legacy and posterity to the fore.
Who is a creative person (not a writer) who has influenced you and your work?
One day in my early 20s, I was walking around the Paris Metro and I saw a cassette under a bench. I picked it up and saw the name Charlie Parker on it. I didn’t know who Charlie Parker was. I took it back to my apartment and just fell in love with it. I listened to it thousands of times. It became part of my brain.
He was a genius, for sure, but in his first gig, the drummer got ticked off and threw a cymbal at him. He went back and worked at his craft. There’s something that anyone who’s a musician or a visual artist or a filmmaker can aspire to: that unbelievable spontaneity that comes from really knowing what you’re working with. I know I’m no Charlie Parker, but he provides this model for hard work, initially, and later on, the kind of spontaneity that’s almost invisible.