In the late sixteenth century, the region surrounding the German city of Trier experienced an outbreak of witch-hunting that shocked Europe. In preceding decades witch trials had already become considerably more virulent; chain persecutions sometimes led to dozens of burnings. But what happened in the Trier region sensationally exceeded that. It all started rather small, with a few accusations against citizens from Trier, who were allegedly seen at nightly witches’ sabbaths. But those few insinuations proved contagious. During investigations through torture, the suspects confessed to alleged witchcraft crimes, such as weather magic that aimed to destroy crops. The accused implicated others, and a fateful chain of accusations began.

From 1586 onwards, remarkable things happened that had remained absent in previous persecutions. Young boys confessed to having attended large witches’ sabbaths and mentioned names of accomplices. While accusations mostly focused on poor women, this time names of wealthy citizens were mentioned too, and even the name of the town’s richest man and president of the university, Dietrich Flade. Earlier on, Flade had been an avid witch-hunter himself, but in 1589 he was burned at the stake, as happened to dozens of others in the city. In the neighboring countryside, the witch-hunting virus got even more out of hand. Spontaneously organized witch-hunt committees killed hundreds of people within a few years. The worst outbreak occurred in the small territory of the imperial abbey of St. Maximin, where around 500 people were killed, representing one-fifth of the population. Like a major epidemic, the panic left some villages largely depopulated.

The consequences did not remain restricted to the region. The new stories about child witches, rich witches, and large sabbaths spread like harmful germs throughout Europe. The Trier model of witch-hunting infected many brains. Subsequently, trials in other places were fueled by wild accusations from children, and some persecutions killed hundreds of people from nearly all social categories. These new contagious notions about witchcraft could have a long incubation period: persecutions only arose years after the novel ideas had arrived. Only after 1630, when many areas had become immunized, did the witch-hunting virus finally begin to wane. But for tens of thousands of victims, that came too late.

The idea that witch hunts spread like a contagious disease is not new. “The germ of witch-hunting could pass from town to town”, wrote one leading historian. “Lists of accomplices could turn endemic persecutions into epidemic ones”, a further expert said, while yet another wrote that major persecutions were “parasitic”. But what exactly should we think of such resemblances? Are they merely coincidental, only useful as a metaphor, or do they reveal deeper similarities? Historians are traditionally dismissive of comparisons between the evolution of living nature and history. History is thought to be far too complex and capricious to be captured in general principles. But what if we take the aforementioned comparisons seriously? What new insights might that bring?

In recent years, my doctoral research has aimed to answer questions like these. I’ve explored whether there are Darwinian mechanisms behind the evolution of witch-hunting phenomena. Viruses, for instance, are known to be extremely well adapted to reproduce within their environment. They make people cough and sneeze, for example, which enables them to infect others through the air. It appears like an intelligent design, but in fact, it was only a blind Darwinian process that did the manufacturing: variants that were accidentally adapted were cumulatively preserved in repeated rounds of selection. Biologists call this “design without a designer.”

Strikingly, many past historians have observed that the early modern European concepts of witchcraft also look as if they were intelligently designed to unleash big persecutions. Take the idea that witches knew each other from a witches' sabbath, where they allegedly received instructions from their master, the devil. This was an illusion, but the notion could still make accusations against a few persons escalate into chain persecutions for hundreds of people. Or take the belief that witches could fly to these sabbaths, for instance on a broomstick. This implied that witches knew each other over great distances, often resulting in witchcraft accusations spreading over long distances. The notion of witch-children also contributed to witch-hunting’s spread, as childish fantasy easily made witchcraft accusations run riot.

No wonder past historians have been looking for the crafty designers behind it all. Was it perhaps Catholic inquisitors who created the phenomenon for their malevolent purposes, like oppressing the poor, or women? Or were witch-hunts used by rising urban elites, who aimed to destroy a traditional peasant culture in which old women played an essential role? Or was it just a means to make money, or to get rid of personal enemies? Yet another proposal was that witch-hunting strengthened the social solidarity of communities through the attack on a common enemy.

Most historical experts today reject such explanations for want of evidence. In historical sources, like pamphlets, news sheets, sermons, scholarly works, and trial records, witch-hunt proponents did not discuss how to oppress women, subdue the common people, or destroy peasant culture. Diabolical witchcraft was discussed as a real threat that needed to be eliminated. Of course, the real motivations may have remained concealed, but an additional problem is that the course of witch persecutions does not indicate a hidden plan either. It was highly diverse who took the initiative and who became the victims. Accusations often came from below, and in many cases, the authorities were unwilling to take things any further. There was a significant overrepresentation of women among the victims, and misogyny was clearly a part of the picture. But still, around 20-25 percent of the victims were men, and accusations also regularly came from women.

In the case of a shrewd underlying design, we should expect persecutions to have been organized systematically, but that was not the case. Witch trials normally occurred unplanned and haphazardly, for instance after strange weather conditions or other misfortune. This again indicates outbreaks of genuine panic about the witchcraft danger. How persecutions unfolded was difficult to predict, and the consequences for society were often dramatic: economic damage disrupted communities, and ruined social relations. Neither was Dietrich Flade the only one who contributed to witch-hunting but was then burned as a witch himself. In short, none of this hints in the direction of an intelligent design by people pursuing their hidden interests. As one famous expert put it: “The implementation of witchcraft persecutions spread contagiously, but any politically coordinated effort with that direct intent was conspicuously lacking.”

This brings us back to the comparison of epidemics. What if we look at the witch-hunting phenomenon as a cultural “virus”? New variants of witch belief continually appeared, most of which quickly vanished. Only the variants that were best adapted for propagation within their particular environment survived, such as the belief in large witches’ sabbaths, flying witches, or child witches. In the Trier region, these variants led to unusually large persecutions, which then attracted widespread attention. Subsequently, it was these cultural variants that found their way into many new brains, stimulating similar outbreaks elsewhere. The people supporting witch-hunting do not seem to have grasped this reproductive logic. But within a Darwinian framework that does not necessarily matter: it was a cultural design without a designer.

This comparison to epidemic disease can teach us another important lesson. Take the rabies virus, the mad dog’s disease, that manipulates dogs’ behavior. Once this virus has entered a dog’s brain, it turns these animals into restless wanderers with foaming mouths, ready to bite each and every one. The question of what function this behavior fulfills for the dog will not bring us any further; in fact, it is highly dangerous for the dogs themselves. But when we ask ourselves what function this behavior has for the spread of the rabies virus, all of it suddenly makes perfect functional sense. Through the aggressive biting, the virus particles enter new carriers, there to survive another day.

This is also how we can look at the witch-hunting phenomenon. The question of what function ideas such as the witches’ sabbath, flying witches, or child witches had for the people involved, or for their communities, does not necessarily bring us any further. For them, it was often harmful. But when we look at it from the reproductive angle of the witch-hunting phenomenon itself, all of it makes perfect functional sense. These cultural variants were ingeniously adapted to make this cultural “virus” spread. Similar to the rabies virus, the cultural phenomenon manipulated the behavior of its carriers – in this case early modern Europeans – for the benefit of its own reproduction.

The witch hunts have become history and may appear alien to us now. But if the viral interpretation is correct, this historical episode carries important lessons for today. Are there cultural phenomena in our world that exploit their human carriers to ensure their own reproduction? Our increased understanding of biological diseases has greatly helped humanity defend itself against those pathogens. So might a better understanding of harmful cultural “viruses” also aid humankind? If it produced only a fraction of the successes of our medical fight against biological disease, the efforts would be worth their weight in gold.

For tens of thousands, immunization against the witch-hunting concept came too late. By pursuing mental immunity research now, we may well spare others a similar fate.


Steije Hofhuis, Qualitative Darwinism: An evolutionary history of witch-hunting. 2022. Utrecht University Repository (Dissertation). Link: