MIDDLETOWN, Conn.

THE Enlightenment polymath Denis Diderot turns 300 this year, and his October birthday is shaping up to be special. President François Hollande has indicated that he plans to honor the philosopher and novelist with what may be France’s highest tribute: a symbolic reburial in the Panthéon. In the roughly two centuries since this massive neo-Classical church was converted into a secular mausoleum, fewer than 80 people have been admitted into its gravestone club. If inducted, Diderot will arguably be the first member to be celebrated as much for his attacks on reigning orthodoxies as for his literary stature.

Like many Enlightenment writers, Diderot preached the right of the individual to determine the course of his or her life. But the type of liberty that underpins Diderot’s body of work differs markedly from today’s hackneyed understanding of freedom. His message was of intellectual emancipation from received authorities — be they religious, political or societal — and always in the interest of the common good. More so than the deists Voltaire and Rousseau, Diderot embodied the most progressive wing of Enlightenment thought, a position that stemmed from his belief that skepticism in all matters was “the first step toward truth.” He was, in fact, the precise type of secular Enlightenment thinker that some members of the Texas State Board of Education have attempted to write out of their high school curriculum.

Rare are the writers whose legacy has shifted as dramatically as Diderot’s. When he died in 1784, at age 70, the vast majority of his short stories, novels and philosophical works lay hidden away in trunks. He was remembered primarily for two things: coediting the world’s first comprehensive encyclopedia, a project to which he contributed an astonishing 10,000 articles, and being a scandalous freethinker and atheist.