Montaigne was a Deist, but refrained from candor about his beliefs due to the mutual slaughter between Catholics and French Huguenots of the time. "It is setting a high value upon our opinions," he wrote, "to roast men and women alive on account of them."

Ernest Renan, who did not believe in a future life, once said, "I know that when I am dead nothing of me will remain." He remained a Pantheist throughout his life.

To a census-taker, who asked him in 1872 if he was a Catholic, Hugo replied, "No. A Freethinker." Hugo predicted that Christianity would soon disappear, but men would still believe in God.

Although he was agnostic, the Catholic-born Moore he preferred to be regarded as a Protestant – even though Protestants, too, found his ideas about Jesus troublesome.

Boito’s only completed opera, “Mefistofele,” based on Goethe's “Faust,” infuriated the Italian clergy by his frivolous treatment of religion.

The astronaut portrays an Enlightenment intellect confronting an “ape” culture of ingrained religion and superstitious beliefs. Free thought (or Freethought) is a crime and heaven help anybody who claims the truth of evolution!

“I'm an Atheist,” says Angier. “I don't believe in God, Gods, Godlets or any sort of higher power beyond the universe itself.... I'm convinced that the world as we see it was shaped by … evolution through natural selection.”

"The spirit of dogmatic theology poisons everything it touches," said Bentham. "There is no pestilence in a state like a zeal for religion, independent of morality."

"It vexes me when they [clerics] would constrain science by the authority of the Scriptures," wrote Galileo, "and yet do not consider themselves bound to answer reason and experiment."

In a note to Donny and Marie Osmond, Penn wrote, 'There is no god,' and Teller wrote, 'He's right.'"