Daniel C. Dennett, the author and philosopher known for his work on cognitive science and for his vehement atheism, has died at 82, the New York Times reports.

Dennett, a Boston native, was educated at Harvard University and the University of Oxford, and taught for years at the University of California, Irvine, and Tufts University. He made his literary debut in 1969 with Content and Consciousness; several more books would follow, including Brainstorms, Consciousness Explained, Darwin’s Dangerous Idea, and Breaking the Spell.

Dennett was a pioneer of the New Atheism movement, which urged adherents to challenge religious orthodoxy in public life. In 2019, he co-authored a book, The Four Horsemen, with three other New Atheism figures, Christopher Hitchens, Richard Dawkins, and Sam Harris.

His most recent book, I’ve Been Thinking, was published last October. In a starred review, a critic for Kirkus called it “a delightful memoir from one of our deepest thinkers.”

Dennett’s admirers paid tribute to him on social media. On X, formerly known as Twitter, social scientist David Pinsof wrote, “RIP Daniel Dennett. He was the best kind of philosopher—empirically-minded, skeptical of ‘intuition pumps,’ and eminently readable. His idea of Darwinism as a ‘universal acid,’ a substance that eats through everything, has been deeply influential on me.”

And psychologist Paul Bloom posted, “Such sad news. He was a brilliant philosopher who had a profound influence on cognitive science. And he was hugely supportive to young scholars—including me, long ago. A great loss.”

Michael Schaub is a contributing writer.