An Official Guide for Demon Hunters: Helpful Advice from Theologians and Witch-Hunters, by Stephen T. Asma, PhD

Following is a very helpful guide to the demon hunters among you by friend of Morbid Anatomy Dr. Stephen T. Asma. Dr. Asma might already be known to some of you as the author of Stuffed Animals and Pickled Heads, the book which inspired me take to the road to photograph medical museums on a trip which led to the founding of Morbid Anatomy He is also the author of the equally thoughtful On Monsters.

An earlier version of piece was originally published in 2014 on the Morbid Anatomy Blog.

Saint Anthony

The story of Saint Anthony of the Desert (above image; c.251-356) had a huge impact on the development of demonology. He is sometimes referred to as the Father of Monks, having created a desert monasticism that drew Christian ascetics far away from the urban centers. But his famous fight with demons in the Egyptian desert also laid the groundwork for all subsequent thinking about demons and possession. (1) 

Questing after spiritual purification, Anthony left the pleasures of domestic life and moved to live in a tomb outside his village, where he was attacked by a “multitude of demons” who sliced him into a bloody mess. “For he affirmed that the torture had been so excessive that no blows inflicted by man could ever have caused him such torment.” But his faith revitalized him and he rallied back. After throwing off the temptations of the flesh, Anthony was revisited by the devil many times –but the devil always shape-shifted to appear as some creature. “Changes of form for evil are easy for the devil,” Anthony explained, “so in the night they make such a din that the whole of that place seemed to be shaken by an earthquake, and the demons as if breaking the four walls of the dwelling seemed to enter through them, coming in the likeness of beasts and creeping things.”

The Temptation of St Anthony, Hieronymus Bosch, circa 1501, Museu Nacional de Arte Antiga, Lisbon

But most demons, Anthony assures us, have no real power in the physical world. They only seem to be causally efficacious. The trick is to acknowledge that you are having a frightening experience, but realize that the frightener is like a hallucination rather than a material creature. In fact, reading St. Anthony is like reading an early self-help treatise for schizophrenics.

The Temptation of St. Anthony, by Joos van Craesbeeck, c. 1650

In addition to demons who shape-shift into frightening phantasms –which are easily banished by a resolute sign-of-the-cross –Anthony acknowledges the phenomenon of real human possession. This is somewhat difficult to square with his persistent claim that demons have no real power. In the last half of the Life of Anthony, Athanasius tells of many terrible cases of people who have come into the custody of demon spirits. A man named Fronto, for example, had a madness that involved biting his own tongue and injuring his own eyes, a woman from Busiris had mucus fall from her nose that immediately turned into worms once it hit the ground, and “another, a person of rank, came to him, possessed by a demon; and…he even ate the excreta from his own body.” And this young man actually attacked Anthony, but the sage said, “Be not angry with the young man, for it is not he, but the demon which is in him.”

Anthony cured all these cases and many more, but it is unlikely that the man eating his own excrement would have agreed with Anthony’s refrain that demons are powerless. And, for that matter, if they are truly powerless, why would anyone need Anthony’s exorcising acumen? The logic here can be reconstructed perhaps by saying that demons do not have real power unless you become afraid of them, in which case you grant them entry into the cause-and-effect world. Our response to demon attack can either give them causal traction in our world or banish them from it. We are instrumental in the outcome of the encounter.

Saint Augustine 

Anthony’s demonology was further refined by many Church Fathers, including Saint Augustine and Saint Thomas Aquinas. Augustine, for example, took pains in his City of God to distinguish earlier positive uses of the term “demon” (by pagans like Socrates), from the only truly positive spirit beings –the “angels.” The pagans, he argued, were aware of angels and demons, but not as such. Heathens lacked the Christian truth and therefore misinterpreted their occasional encounters with the spirit realm – imagining a pagan theology where they should have seen a monotheism. 

But more interestingly, Augustine delved into the psychology or epistemology of the demon mind – arguing that demons have knowledge but their knowledge is not sanctified by a sense of charity

The Fall of the Rebel Angles, Pieter Bruegel the Elder, 1562, Royal Museums of Fine Arts of Belgium, Brussels

Citing Corinthians, Augustine says “Knowledge puffeth up, but charity buildeth up,” and he uses this point to connect demonic psychology with pride. (2) In a tour de force of hermeneutics, he further shows that this is why human pride is empty of charity and indistinguishable (except perhaps by degree) from demonic psychology. Demons, he says, are capable of getting the outward shell of Christ’s message, but not the inner meaning. Demons have knowledge, but it is sterile. And the important difference between demonic and angelic knowledge is spelled out. “The good angels, therefore, hold cheap all that knowledge of material and transitory things which the demons are so proud of possessing.” (3) Perhaps the good news for humans in this picture is that because demons focus, like humans, on the transitory changing world, they can be deceived. They, like us, live in the world of shadows, and passions can agitate them as well. That means their own emotions can be used against them, by the clever demon hunter. Angels on the other hand (and Saints), behold, in the wisdom of God, the eternal “cardinal causes” of things, and so they are never deceived.

Augustine instructs us about the imperfect minds of demons, but also offers some insight into their mysterious bodies. He asks the Christian reader not to feel envy about the demon’s amazing “aerial bodies” – capable of becoming invisible, floating, flying, shape-shifting, and even passing through walls. He points out that many animals too have greater bodily powers of strength, perception, and speed, but humans are more than compensated with the infinitely important faculties of rationality and virtue.  Okay, demons have really impressive magical bodies, but “divine providence gave to them bodies of a better quality than ours, that that in which we excel them might in this way be commended to us as deserving to be far more cared for than the body, and that we should learn to despise the bodily.” (4)

Fragement of The Fall of the Damned, Dirk Bouts, c.1470

Saint Aquinas

Writing almost nine-hundred years later, Aquinas is still refining Christian demonology and giving nuance to the ideas first formed by St. Anthony. In his Summa Contra Gentiles, Aquinas considers whether demons are inherently evil. He offers some standard theological and scriptural ways of thinking about demons and monsters. “Nothing can exist unless it has existence from the first being, and the first being is the sovereign good. But since every being, as such, acts to the production of its own likeness, all things that come of the first being must be good.” And he caps this theological claim with some scripture – “This is also confirmed by the authority of Holy Scripture: for it is said, Every creature is good (1 Tim. iv, 4): God saw all things that he had made, and they were very good (Gen. I, 31).” (5) This means demons are not intrinsically evil, and Aquinas gives a philosophical argument for this surprising view. (6)

He starts from an old premise about the way that conscious beings make decisions and act. Conscious beings, which would include humans but also aerial-bodied demons, and even angels (but not lower animals), always act for the sake of some perceived good. They may be wrong about it, but at least they are moving in a direction that seems beneficial to them in some way. Imagine, for example, that you’re late for an important event. You are pushing a crowd of people in the street in order to get to your destination, and some people are injured in the scuffle. Their suffering is not your intended goal or motivation. Their suffering is an unfortunate but unintended consequence of your over-zealous sense of punctuality. You are not guilty of knowingly and willfully hurting other people –but you are guilty of being careless and thoughtless about the safety of others. You’re not excused for the harm you’ve done, but you’re not an inherently harmful or intrinsically evil person either.

Aquinas thinks this point extends to the demons as well. The wider popular culture believes demons to be inherently evil beings that intentionally seek the pain and suffering of others as their only real goal and purpose. But Aquinas thinks demons are confused and weak-willed – accidentally evil, not essentially evil. (7) When those demons tortured St. Anthony, for example, they were motivated by their (admittedly selfish and wrongheaded) sense of good. Like other cases of evil and sin, the suffering of St. Anthony is the result of a “false judgment” rather than a “bad will.” The only other way, theoretically, for a demon’s will to be truly bad would be if it were tied to a faulty faculty of understanding – one that would always misjudge, always make a false judgment. But, according to Aquinas, “false judgments” (e.g. thinking heroin might be good for one’s children, or thinking hemlock would make a good snack, etc.) are actually freakish occurrences, not the norm. “False judgments in acts of the understanding” he says, “are like monsters in the physical universe, which are not according to nature, but out of the way of nature: for the good of the understanding and its natural end is the knowledge of truth.”

One suspects that Anthony, and other victims of demon torture, would have found this nuanced theory to be cold-comfort. This more sophisticated view of conscious agency hardly takes the sting out of the demon’s venom. A demon’s victim might retort: So, if they’re not intrinsically evil, then why are they causing me so much pain and misery? In fact, more crucially, if there’s no real “bad will,” then whence comes sin? The answers are interesting. With impressive consistency, Aquinas claims that the demon’s volitions are still only good (by definition), but the demon has failed to submit his own personal good to the higher, superior good (God’s will). The demon’s sin is the failure to restrict his own agenda of perceived personal goods to the cosmic perfect good of God’s benevolence.

Aquinas analyzes the fall of the prince of demons himself, Lucifer, and finds a perfect illustration of his general theory. 

 Lucifer, Franz von Stuck, 1890, National Gallery, Sofia

Even the devil is not naturally or essentially evil. Referring toIsaiah (chapter xiv), Aquinas says that the devil did not properly impose the Higher Good upon his own. Lucifer’s will “was not regulated by any higher will, a position of independence proper to God alone. In this sense we must understand the saying that he aimed at equality with God, not that he ever expected his goodness to equal the divine goodness: such a thought could never have occurred to his mind. But to wish to rule others, and not to have one’s own will ruled by any superior, is to wish to be in power and cease to be a subject; and that is the sin of pride.” (8)

Satan in his Original Glory: ‘Thou wast Perfect till Iniquity was Found in Thee’, William Blake, c. 1805, Tate Gallery

Now we know what makes demons tick, so to speak. There is no evil “force” or “power” skulking about in the shadows of our world. Demons are not, contrary to popular opinion, embodiments of this imaginary evil energy. (9) They are instead, aerial-bodied agents with conscious volition who confusedly seek their own self-aggrandizement – in other words, they are meaner versions of ourselves, who can also shape-shift and turn invisible. 

Strangely, the issue of sadism (actually taking pleasure in another’s pain) does not seem to have occurred to Aquinas. At least he prefers to analyze demonic deeds in the context of prideful power struggles for recognition –the torture techniques of demons are just their means to the end of “conversion to the dark side” or their coercive attempts to get reverence, and other similar sins of pride. Aquinas does not seriously entertain the idea that the misery of the tortured human is the pleasurable end goal of the demon’s activity. (10)

The Witch-Hunter, Institoris

In 1484 Pope Innocent VIII gave Dominican inquisitor Heinrich Institoris wide ranging legal powers to pursue and eradicate witches (Papal Bull Summis desiderantes affectibus). The Bull was used as a justificational preface for Institoris’ famous demon hunting guide Malleus Maleficarum.

Title page of an edition dated 1669, via Wikipedia

The Malleus Malificarum argues throughout for a “middle-way” position between witchcraft that’s too real (and therefore in violation of God’s goodness and power) and that which is not real enough (purely imaginative and fictional). Earlier demonologists, like Aquinas and the authors of the influential Canon Episcopi, (11) argued that the frightening visions and shape-shifting episodes associated with witchcraft were really just quasi-dream-like phantasms. If any mischievous manipulation is occurring to a man who thinks he’s a werewolf, or experiences aerial lift-off on a broom, then the cause would have to sneak in, according to these more skeptical demonologists, at the physiological juncture where his “imaginative faculty” meets his “interior senses.” 

The imaginative faculty is described as a “treasure house” in each person that stores or preserves visible shapes, like the images of animals for example. It’s a treasure house of memories. If some evil spirit were to trigger this storage faculty just right, then it would flood the perceptual senses and give the person the illusory experience of real external stimuli outside the body. A mundane version of this happens all the time, when bodily humors trigger the “treasure house” in sleep and we subsequently dream.

Institoris breaks with this more benign version of witchcraft, and offers a clever way to get demons back in their threatening positions. Works of evil, according to Institoris, are not just indigestion-like fabrications of the body. They are real and they are happening in the external world; children really are being eaten by demonic were-wolves, the witches are actually taking flight. But how is it done, if only God has true creative power like this?

The Witches' Sabbath, Hans Baldung Grien, 1510, The British Museum

Demons according to Institoris do not make something from nothing when they enact their transgressions –that would truly violate a cardinal notion of the monotheistic God. It may seem that demons and their witches conjure monsters and terrors from thin air, but they do not really create in such an absolute manner. Instead, the demons have an amazing understanding of the Book of Nature. They grasp the first principles, fundamental springs, and material trajectories of physical nature itself. Demons are manipulative “scientists” long before this term even existed. They are the ultimate alchemists. (12)  

When demons do shape-shifting and other seemingly supernatural marvels, they are not “creating” so much as “altering” nature. According to Institoris, the evil ones sift the matter of nature to find the seeds (semina) of transformation, and then use these micro-agents as catalysts for their own nefarious inventions.(13) Demons transform nature more by chemistry than by magic. Just as the form of the oak tree exists like a germ in the acorn, so too all of nature is filled with micro-seeds that when triggered alter the perceivable world in significant ways. 

Demons understand these mechanisms, which are invisible to humans, and they engineer outcomes in ways that look miraculous to us. By this subtle knowledge of nature, witches appear to predict the future, but they cannot really see the future (as God can). (14) In this way, Institoris explains how demons and witches “create” mayhem in the world, but he avoids the heresy regarding ex nihilo creation. Demons simply alter nature in ways that scare and frighten us, and seem supernatural. (15) 

But now we see why “God’s acquiescence” is frequently intoned in the Malleus explanation of witchcraft. The logic is this. Even if witchcraft is only altering nature, rather than “creating” it, it’s still doing significant damage in the world. Nature is being altered by demons in ways that allow witches to kill their neighbors with effigies and pins. 

Photo by author, wax poppet from the "Curses or Natural Justice" section of the Museum of Witchcraft, Boscastle 

And letting insignificant chump-demons and their paltry witch covens undo the beautiful divine cosmic plan would reflect very badly on God, unless God was actually giving his permission for this suffering. Why God gives His permission to let demons and witches turn someone against his neighbor is really beyond the speculative power of the demonologist. Institoris doesn’t really need to understand his target, he only needs to punish him.

The Witches' Sabbath, Francisco Goya, 1798, Museo Lázaro Galdiano, Madrid

Those who were possessed, however, were considered differently than witches. In the case of possession, the person afflicted was not considered to be evil or malicious, but rather set-upon (not entirely responsible for their actions). In these cases, their demonic behavior could be exorcised and they could be restored to fully human status. Interestingly, Institoris notes that when exorcism fails after multiple attempts, then the victim may have been misdiagnosed and probably deserves their condition as a divine punishment.

If your demon hunting catches a possessed person, a typical exorcism is outlined by Institoris. (16)  It’s best if a cleric performs the function but anyone of good character can do it if necessary. First, make the afflicted person give a confession. Next do a careful search of the home to detect any magical implements (e.g., amulets, effigies, etc.) and burn these. It’s important to get the afflicted into a church at this point, and make he/she hold a blessed candle while righteous witnesses pray over her. This should be sustained three times a week to restore grace, and the victim should receive the holy sacrament. In stubborn cases, you should write the beginning phrases of John’s Gospel on a tablet and hang it around the person’s neck --holy water should be applied liberally. If exorcism ultimately fails, then either the person is being punished by God and has to be surrendered, or your faith, as the exorcist, is not strong enough (and new administrators should be brought in).

In closing then, always remember to employ the three tried-and-true weapons of the demon hunting arsenal; prayer, fasting, and faith. Anthony first recommended these low-tech strategies, and they remain the bread-and-butter of demon hunting. But new armaments, especially the antipsychotic Clozapine, have also proven themselves crucial in 21st century demon management. Go forth and mollify.


1. Anthony’s marvelous episodes have also fueled the pictorial tradition, from the medieval period to the present. Paintings by Heironymus Bosch, Matthias Grunewald, and Salvadore Dali, for example, have helped to keep Anthony’s tribulations in the popular imagination. Anthony’s battle with monsters comes to us via his famous biographer Athanasius of Alexandria (c.293-373). Athanasius chronicled Anthony’s life in a work titled simply Vita Antonii, orLife of Anthony. The book was eventually translated into Latin and set the template for subsequent medieval monastic biographies. Athanasius is revered in all the major sects of Christianity as the first Church Doctor. He served under Alexander of Alexandria, until succeeding him as Patriarch of Alexandria, and may have accompanied Alexander to the First Council of Nicea in 325. Athanasius was adamant to stamp out the popular theory about Christ, called Arianism, named after another Alexandrian theologian named Arius (c.250-336). Arians believed that God created Christ –Christ is not the same substance as God. This was anathematized by the Nicene Creed, which makes Christ, and the Holy Spirit, consubstantial with God the Father. Athanasius’ position, that the holy trinity is the same being (homoousia in Greek, or essentia in Latin) and all are eternal, became the orthodox theology for Christianity. But this orthodoxy was not established until after a sustained attack on Arianism as heresy, some of which occupies the later sections of the Life of Anthony.
2. See I Corinthians, Chapter 8, 1.
3. See Book IX, 22.
4. See Book VIII, 15.
5. See Aquinas’s Summa Contra Gentiles, Chapter CVII. Quotations are drawn from Joseph Rickaby’s, translation (London: Burns and Oates, 1905).
6. The starting premise of this argument, indeed this entire way of looking at agency, is derived from Aristotle’s (and even Socrates’) view that conscious action is always teleologically arranged toward the perceived good of the actor. Aquinas, and most Christian theologians adopt this starting point, but also add unique considerations (that did not trouble the ancients) about the relevant mechanisms of sin.
7. To get the full sense of Aquinas’ argument we have to understand his rather different notion of “causality” and the old essential/accidental distinction. Causes produce effects that are similar in kind to their causes. Conscious goals are causes of actions/effects. Since a conscious goal is by definition a kind of “good” (a perceived good at the very least), and since such goals are causes, then Aquinas thinks it follows that a person’s intentions can only cause evil “accidentally.” The cause is essentially good, and therefore no evil can flow from it –so any evil that results is incidental. Finally, he thinks, this proves that evil (which is always caused incidentally) is not a real metaphysical presence in the world (a real causal force), but only a kind of unpleasant epiphenomenon. “For no agent acts except with some intention of good: evil therefore cannot be the effect of any cause except incidentally. But what is caused incidentally only cannot be by nature, since every nature has a regular and definite mode of coming into being.” (Chapter CVII).
8. See Chapter CIX.
9. Here Aquinas tows a line first laid out by Augustine against the Manicheans. The Persian notion of evil is this idea of a cosmic metaphysical force or power –something outside of God and His control. In silencing this heresy, Augustine redefined “evil” to mean a “privation” or “lack” of a good. Evil is not a positive reality, but a purely negative adjective that people mistake for a “thing.” The word “evil” might be considered more like the word “shadow” in the sense that it picks out something particular, but in reality a shadow is just the absence of light. It is nothing in itself.
10. Aquinas can counter the sadism point (and maybe even the more difficult masochism issue) by pointing out that the true telos (end goal) is the pleasure enjoyed, not the harm. But the modern mind finds this protest somewhat naïve in the sense that sadism means that a certain kind of pleasure is only attainable in the harming. To use his own lingo, there may be an essential causation between the harm and pleasure.
11. The Canon Episcopi is probably a ninth century Frankish document (sometimes thought to originate in the fourth-century), and its short text on witches had become Canon Law by the time of the Malleus. It characterizes the more “psychological” theory that I’ve been sketching, and that Institoris was reacting against. Roughly speaking, witches are just very confused about their own powers and experiences (delusions), but this still makes them dangerous heretics because they tend to infect other innocents with their promises of Satanic power and that betrayal is still real (even if the magical powers are imaginary). The Canon Episcopi famously formulated the scenario of groups of women (hallucinating themselves to be) riding through the air for great distances.
12. Alchemy had been a positive part of Islamic scientiafor centuries, but when the texts and ideas flowed into Europe (after the Moor expulsion) it came to be seen as a threatening alternative knowledge base (with infidel origins). Alchemy became associated with the black arts and heresy, but ironically many of the “research programs” of alchemy (e.g., the transformation of natural substances) became the foundations of later chemistry. Dominicans like Aquinas and Albertus Magnus, together with Franciscan Roger Bacon, originally tolerated alchemy, trying to submit its claims to rational criteria. But by the fourteenth-century alchemy was outlawed in many places. See Chapter One of Roslynn D. Haynes’ From Faust to Strangelove (Johns Hopkins University, 1994).
13. The idea that nature is filled with invisible seeds of transformation (rationes seminales) was very useful to theologians like Augustine, who used the concept whenever he needed to explain natural growth, development, or evolution in a monotheistic paradigm of “fiat creationism” that precluded such transformation. Ecclesiasticus 18:1 states that all things were created by God simultaneously (qui vivit in aeternum creavit omnia simul), but Genesis gives us a staggered creation over time. Augustine’s idea of “germs” of forms existing within other forms helped to make consistent the unrolling of creation and the simultaneous miracle of creation. Institoris seems to be drawing on this tradition to help him explain demon “creative” power.
14. Institoris, in defense of his demonology, cites a gloss on Exodus 7 (when Pharao’s magicians also made serpents from staffs), which says, “When workers of harmful magic try to do something by chanting [the names] of evil spirits, they [the spirits] run off in different directions through the world, and in a very short time bring back the seeds of those things with which they stimulate this [process], and in this way, with God’s permission, produce new forms from these.”
15. Institoris points out that such demonic “alterations” of nature can never violate the ways of nature (e.g., bring a dead man to life), but only speed-up, slow-down, mix or otherwise mutate changes that could happen anyway (theoretically).
16. See Chapter 6, Part II.

Top image: Attributed as copy by the young Michelangelo after an engraving by Martin Schongauer around 1487-9, The Torment of Saint Anthony. Oil and tempera on panel. One of many artistic depictions of Saint Anthony's trials in the desert. Via Wikipedia


Stephen T. Asma (born 1966) is Professor of Philosophy and Distinguished Scholar at Columbia College Chicago. He is also a Senior Fellow of the Research Group in Mind, Science, and Culture at Columbia College Chicago.

He works on the philosophy of the life sciences, and the theme of Religion and Science (especially Buddhism and Christianity). He is considered an authority on the history and philosophy of monsters and horror.  Additionally, he works on the philosophy of improvisation and imagination. Asma was a Fulbright Scholar in Beijing China in 2014. He writes regularly for the New York Times, The Stone, and various magazines.

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