If you want to understand secularism, Emily Ogden reminds us in Credulity, then you can begin with the art of debunking. Secularism is not only a political project; it is also a way of claiming authority on stage, on the page, and in other popular media. Calling out the frauds and the deceivers, secularism would prove, again and again, that there are no mysteries in the world. Secularism’s bad objects are many and various—priestcraft, hokum, fetish, sleight-of-hand—but it would do the same thing to them all. Secularism would authorize itself, indeed it would summon itself into being, by disenchanting all this bunk.

Ogden’s marvelous book shows what secularism loves and not just what it hates, what it desires and not just what it wishes to get rid of; Credulity is, among other things, a study of “debunking’s pleasures.” Could it be that the object of debunking matters less to the secularist than the act itself? Could it be that what secularism really wants is not to banish false prophets but to trot them out, endlessly, so that it can demonstrate its mastery over them? “Debunking begets more debunking,” Ogden observes. Rather than putting the stake in the heart of error, “the debunker actually needs to find, even elicit, more credulity on which to work.” Not all secularists are atheists, you know. Some of them want to debunk bad, false religions so they can make a stronger case for the one religion they hold true. Secularists can keep a god, as long as they can keep debunking, too.

But debunking is a tricky business. You might even say it is something of a shell game. It sets out to destroy; it means to dispel an illusion. It drains the spirit from the idols, and it shows that the magic wand is an empty stick. And then, having cleared the air of ghosts, the debunker finds that the work is not quite done. A question lingers, something more difficult to be explained. How can a delusion—a belief in something that is not real—have such powerful, palpable effects on the believer? Witnessing a scene of mesmerism, how can the secularist account for the convulsions, the trances, the peculiar manifestations of second sight? If there is no such thing as animal magnetism, then what is the true source of this weird action?

It might be tempting to accuse the mesmerized person, the “medium,” of collaborating in the fraud. However, such an explanation does not serve the enterprising secularist. Keep this in mind about debunkers: they are waging a contest for authority against the ones whose mystifications they presume to undermine. They want to unmask the frauds so they can win the favor of the dupes. The debunker therefore tends to grant to the deluded a kind of good faith. After all, if everybody is faking it, if the marks are in on the con, then nobody is really deluded; in that case, the debunker comes off as a killjoy, the kind of fellow who denounces the inauthenticity of professional wrestling or pornography. (Who can read Theodor Adorno’s book about astrology in Los Angeles, The Stars Down to Earth, without a cringe for the author, for just this reason?) The debunker needs not only the false prophet but also the true believer.

And so secularism finds itself searching for some other way to account for the real manifestations of a faith in the unreal. “There is a surprising consequence involved in accusing other people of believing in things that do not exist,” Ogden writes. “The aim is to deprive these idols, these nothings in the world, of their power. And yet the end result is to give some placeholder—‘belief’ or ‘idolatry’ or ‘imagination’—all the power that the idols once had.” After the debunking, it turns out, the mysterious power in question has not been dispelled, at least not all the way. It has been placed inside the deluded themselves. It has been shifted from one shell (the wand) to another (the believer’s head). Subtracting all ethereal magic from the scene, the secularist adds a new element, a susceptibility to false belief, that produces extreme, even miraculous effects right here in the material world. Debunking involves not only an erasure but also the invention, or at least the discovery, of a powerful human capacity for submission to manipulation and control. Following the lead of her sources, Ogden calls this feature of the self credulity.

The subtitle of Ogden’s book is “A Cultural History of US Mesmerism.” She is not the first scholar to reconstruct mesmerism’s history, but she handles the project with an unusual combination of rigor and good humor, and she sees something in that history—the uses of credulity in avowedly secular endeavors—whose significance no other scholar has reckoned with in such illuminating ways. The story begins in Paris around 1778, when the Austrian Franz Anton Mesmer sets up shop. He calls his business animal magnetism. Using magnetized rods, Mesmer manipulates an invisible fluid and produces abnormal sensations and movements in the bodies of his subjects. He also promises to cure their maladies. Imitators and disciples follow Mesmer’s lead. Before long, animal magnetism is the talk of Paris.

French medical experts are disturbed by what they view as junk science, and they do not like the competition from the quacks. To look into the matter, King Louis XVI assembles a committee of eminent scientists, including the chemist Antoine Lavoisier and the American genius Benjamin Franklin. These enlightened investigators conduct a set of experiments, testing Mesmer’s science. They come to the conclusion that there is no fluid. Animal magnetism is a fraud. Like mesmerism itself, their report becomes a popular sensation; it is translated by the English philosopher and gothic novelist William Godwin, and it is widely read around the North Atlantic. In the report, Franklin and his colleagues attribute the sensational effects of animal magnetism to the credulity of Mesmer’s patients. The animal magnetism craze, they conclude, is the latest episode in the long history of enthusiasm and fanaticism. Mesmer is no physician; he is just another faith healer.

Nobody in the United States, meanwhile, is practicing animal magnetism. News of the phenomenon arrives in this country by way of the commission’s report. The very investigation that debunks animal magnetism, in other words, is also the one that introduces it and makes it famous. As Ogden explains, “American audiences learned about the triumph of Franklin before mesmerism was ever practiced in the United States, and so for them mesmerism was, first and foremost, an exemplary credulous error.” Mesmerism becomes more or less synonymous with delusion; its debunking is the parable, the cautionary tale of how the gullible—women and the lower classes most of all, of course—could become the puppets of con men and deceivers. According to the enlightened theorists of credulity, the weakest in reason are the strongest in imagination.

The controversy over animal magnetism is an intellectual one, but it is also a contest over money and prestige. In the long run, it leads not to the abandonment of mesmerism but to its instrumentalization. The debunkers do not kill mesmerism. Instead, they allow for its reinvention as the secular magic of manipulating credulity itself. Of course, some of them denounce such manipulation as bad enchantment, the enslavement of innocent victims to the mesmerist’s will. But others see in mesmerism a resource for managing labor and regulating discipline. The project of enlightenment, as the dialecticians teach us, has always been ambivalent about autonomy. It wants freedom for some, but it also wants mastery. Having discovered the power of credulity, it is hard to resist the temptation to wield it.

For a mesmerism that understands itself in secular terms, as the manipulation of belief, the promises are grand: “All the miracles of false religion—prophecy, faith healing, and unquestioning obedience—would become powers of which a technician could dispose.” Charles Poyen, a creole sugar planter, brings the promise to the United States. Poyen studies medicine and learns a little about mesmerism in France, and he claims to have seen his fellow planters in Guadeloupe using animal magnetism on the enslaved. He makes his way to New England and, in time, begins practicing mesmerism there. He gives a lecture tour and publishes a book, Progress of Animal Magnetism in New England, in 1837. He encourages factory owners to employ mesmerism as a method of labor discipline. The former planter and medical student has become a consultant. Credulity, incorporated.

The golden age of mesmerism in the United States lasts just a little while, into the 1850s. The practice is more important to the history of secularist thought than to that of slavery or factory management. And one of Ogden’s virtues is that she does not make it her business simply to debunk the debunkers. She sees how certain styles of secularism make themselves available to regimes of exploitation and social control. But she also acknowledges that the practitioners of mesmerism undergo their own crises of mastery. The relation between the mesmerist and the medium is never simply the relation between an autonomous subject and a vulnerable object. Mesmeric relations are compensatory, mixed, and troubled. They catch people up “in forms of agency quite different from those they originally sought to shore up . . . in conversion, in collaborative storytelling, and in dependence on their alleged dependents.” Practicing mesmerism entails a suspension of disbelief that can look and feel a lot like credulity.

Still, Ogden makes a sharp point about the instrumentalization of enchantment, and I hope I will not be the only one who feels its sting. Revisionist scholarship on secularism has, in recent years, found itself drawn to the promises of enchantment. The agent of secularism—autonomous, rational, self-governing—has become a prime target of critique; we have come, more and more, to see disenchantment as a ruse of its own, an ideological fiction of capitalism and a justification for imperialism. In light of disenchantment’s complicity in systems of domination, enchantment takes on new features. “Exterior to patriarchy, liberalism, secularity, and Whig history,” Ogden argues, “radical enchantment has stood for our hopes. It has stood, and continues to stand in American studies, for an avant garde aligned with marginalized subjects.” But Ogden’s book makes it clear that even avowedly secular styles of domination have always sought to exploit credulity—not to dispel it but to cultivate it, indeed to master it, in others. Enchantment may be little more, in some cases, than a pleasurable affect that soothes and consoles the disempowered.