In one of the most haunting images in Western art, a man lies slumped over his desk while monsters gather in the darkness behind him. A strange creature stares ominously out at the viewer. Owls circle overhead. Bats swarm through the air. Reason itself has fallen asleep.
The image comes from the Spanish artist Francisco Goya, who, between 1797 and 1799, produced a series of eighty prints titled Los Caprichos, satirizing “the multitude of follies and blunders common in every civil society.” In one of those prints, number 43, titled The Sleep of Reason Produces Monsters, Goya depicts an eerie and menacing scene: the triumph of superstition over reason.
Goya’s message is a clear warning: when reason sleeps, the human imagination—unchecked—can conjure vicious monsters in the form of gods, demons, religions, and the various superstitions for which human history is so notoriously known. It is only when we awaken reason, through philosophical reflection, that we can begin to slay these dangerous dragons—the very creatures we’ve since forgotten were human inventions all along.
The pages of Western history are filled with witches, curses, apparitions, omens, devils, underworlds, prophecies, premonitions, and countless other manifestations of superstitious minds—causing untold misery and destruction in their wake. Against this dark history stand the skeptics, bravely battling these phantoms of the imagination, and, within their ranks, the atheists, who extend the fight to the far more perilous realm of the gods.
Religion is particularly fertile ground for the spawning of monsters. From Thor, Zeus, Mars, and Shiva to Isis, Marduk, Yahweh, and Baal, countless gods have been conjured up in every corner of the globe, dominating human history. But you had better not believe in the wrong ones, else you face the historical prospects of excommunication, imprisonment, torture, and death—and, if you are especially unlucky, eternal damnation. This is the unvarnished history of religion—a history often filled with intolerance, violence, and pain.
But there is an alternative tradition, one seldom told, but every bit as important—and far more hopeful. It is the story of the long struggle against credulity and superstition in their most powerful forms.
It is the story of atheism.
Atheism is not a straightforward story to tell. It has a reputation problem—and not by accident. The word arrives already condemned, burdened with a litany of undeserved charges: nihilism, immorality, hedonism, anarchy—even satanism. These associations were carefully crafted for centuries as its critics labored endlessly to poison the well.
And yet, for all the controversy, atheism makes few explicit claims. The clue is in the name. A-theism is not a doctrine but a refusal—a refusal to accept the existence of gods in the absence of convincing evidence. It sometimes pushes a bit harder and asserts that God almost certainly does not exist. But it never replaces one mythology with another; it simply withholds belief. As far as the atheist is concerned, the gods belong with minotaurs and fairies: products of the human imagination—Goya’s monsters in another form.
If anything is implied beyond this, it’s a welcome shift in concern to the realm of the living. Far from being nihilists or satanists, most atheists care about actual people living in the real world—without the distraction of having to cater to phantoms. In fact, it’s no stretch to suggest that humanism—the position that human reason, science, and ethics should be used to improve life in this world—has become atheism’s natural companion. This more positive (and accurate) association will reveal itself over the course of our history.
Theists, of course, tell a different story. They claim that not only do one or more gods exist, but that they actively watch over us and intervene in daily affairs. The most common form of theism—the classical theism of organized religion—envisions a single personal God who maintains special relationships with human beings and performs miracles at will.
This God—the chief monster of Goya’s vision—has, from the atheist’s perspective, inflicted the most historical damage, making this the main theater of battle: the epic clash between the God of revealed religion and the freethinkers who dared to challenge him.
But I’m careful not to extend the metaphor of battle to the believers themselves. Atheists battle ideas, not people, a fact that proudly sets our cause apart from that of religion—which has, far too often, brought the fight to real human beings, at the stake and on the cross.
So, despite thousands of years of attempted character assassination by the faithful, you’ll find that the history of atheism is surprisingly hopeful—a story filled with nonbelievers as peaceful and virtuous as history can produce. Yet this history is also the prelude to intellectual war. If we want a world ruled by reason, knowledge, and compassion, we must slay the monsters that make us intolerant, ignorant, and cruel.
The specters of Goya’s haunting vision take many forms. In the history to follow, we’ll trace the thinkers who dared to challenge these shapeshifting apparitions—from the natural philosophers confronting the gods of Olympus to the New Atheists battling the God of Abraham. Along the way, we’ll arm ourselves with the weapons forged by these pioneers of freethought—tools of reason we can wield when the monsters, inevitably, return.
Let’s get started where it all began: the birth of religious skepticism in ancient Greece.