This scientific atheism has its roots in the Enlightenment. Leading thinkers of the Enlightenment, like Voltaire, were anti-clerical and anti-religious rather than atheist. Denis Diderot and Baron d’Holbach did, however, introduce a full-fledged atheism to the educated population of Europe. These thinkers viewed science as a privileged form of knowledge based on reason and criticism and testing, and viewed religious doctrine as a form of ignorance rooted in myth, coercion, and fear. As Voltaire put it, “There are no sects in geometry.” That’s because there are methods of verification that enable all scientifically minded people to agree on the facts.

Modern doctrines of materialism and naturalism, which hold that matter is the only reality and that there are no supernatural influences in nature, have their foundation in the atheistic wing of the Enlightenment. Modern atheists have employed these ideas to formulate their influential theories. Marx, for instance, portrayed religion as the “opiate of the masses,” a drug that dulls the mind, preventing it from comprehending the scientific forces acting upon history. Freud, in his 1927 book The Future of an Illusion, termed belief in God a comforting illusion invented by human beings to avoid facing the reality of death. When Richard Dawkins states in The God Delusion that he holds his beliefs “not because of reading a holy book but because I have studied the evidence.” he is placing himself squarely in this tradition of the skeptical Enlightenment.

The Enlightenment critique of religion was not merely an intellectual critique but also a moral critique. This is the case with the atheism of today, which involves a moral denunciation of God’s role in the world as well as a condemnation of the evil influence of religion throughout history. Christopher Hitchens writes glibly of the “moral superiority of atheism.” The leading figure of this type of atheism was philosopher Friedrich Nietzsche. Nietzsche accepted Darwin’s theory of evolution as true, but he detested Darwinism for what he took to be its exaltation of a certain brutish type that survived in nature through raw force. Nietzsche’s atheism is of a very different pedigree than Dawkins’s. Nietzsche would have taken Dawkins’s breed of Darwinism as the mark of a particularly low and unimaginative human type, widely found in England. Nietzsche too was interested in survival of the fittest, but to him this meant the cultural survival of great and noble and artistically imaginative forms of humanity. Nietzsche termed his superior type of human being the ubermensch, or “overman.”