Paracelsus and the Doctrine of Signatures

Summary

Stuff You Missed in History Class: Paracelsus and the Doctrine of Signatures
Release Date: August 6, 2025
Hosts: Holly Fry and Tracy V. Wilson
Produced by iHeartRadio

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Introduction

In this episode of Stuff You Missed in History Class, hosts Holly Fry and Tracy V. Wilson delve into the life and work of Paracelsus, a pivotal yet often overlooked figure in the history of medicine. The episode explores Paracelsus’s contributions, particularly his development of the Doctrine of Signatures, and contextualizes his work within the broader landscape of 16th-century Europe.

Paracelsus: A Rebellious Healer

Holly Fry begins by explaining how the topic of the Doctrine of Signatures was inspired by discussions on another show, Our Skin. She acknowledges that while the doctrine was briefly mentioned previously, it warranted a deeper exploration focused specifically on Paracelsus.

Holly Fry:
"Paracelsus was important in the history of medicine. He's mentioned in a lot of our previous episodes. There hasn't really been an episode focused on him. His life was super interesting. He was a very rebellious person who was frustrated with established medical practice and academia."
[02:58]

Early Life and Education

Tracy V. Wilson provides a detailed account of Paracelsus’s early life. Born Philippus Aeriolus Theophrastus Bombastus von Hohenheim in 1493 in Einsiedeln, Switzerland, Paracelsus was the son of a doctor and chemist. His initial education in metal mining was intended for an administrative role in the mining industry of Villach, Austria. However, Paracelsus’s interest soon shifted towards medicine.

Tracy V. Wilson:
"Paracelsus was born Philippus Aeriolus Theophrastus Bombastus von Hohenheim in Einsiedeln, Sweden, in 1493. As a boy, he went by the name Theophrastus. His father was a doctor and a chemist, and his mother died when he was young."
[07:25]

Paracelsus attended the University of Vienna in 1509, studying mathematics, astrology, and medicine, before moving to the University of Ferrara to obtain his medical degree. Rejecting the traditional academic approach, he believed true medical knowledge came from practical experience and interactions with everyday people rather than universities.

Tracy V. Wilson:
"He felt that a university setting just didn't offer all the information that a doctor would actually need in their day-to-day practice. So he sought out other sources of information and concluded that he could learn more from everyday people."
[09:31]

Challenges and Conflicts

Paracelsus’s progressive ideas often put him at odds with the established medical community. His support for the peasants during the German Peasants War of 1524 further alienated him from his peers, leading to a warrant for his arrest and forcing him to flee Salzburg.

Holly Fry:
"In 1524, he returned to Villach to visit his father before moving north to Salzburg. His plan in Salzburg was derailed by the German Peasants War, and because of his alliance with the peasants, he had to flee."
[10:15]

Despite these challenges, Paracelsus continued to make significant strides in medicine, including treatments that saved lives but were sometimes controversial, such as his use of mercury to treat syphilis.

Doctrine of Signatures

The crux of this episode centers on Paracelsus’s Doctrine of Signatures—a theory proposing that the physical characteristics of plants and minerals indicate their medicinal uses.

Tracy V. Wilson:
"Paracelsus is one of the people who really set up this idea of signatures. He's not the first to have the idea, but he really expounded on it. He wrote a lot about it, so it makes sense to talk about him alongside the Doctrine of Signatures."
[04:44]

Holly Fry explains that before the advent of modern scientific methods, the Doctrine of Signatures served as a heuristic for identifying potential cures based on the resemblance of natural items to parts of the body or ailments.

Holly Fry:
"The idea is that you could intuit the things from nature that might heal a given medical problem by finding ways in which those items from the natural world resembled the ailing part of the body."
[05:32]

Paracelsus’s Rebuke of Traditional Medicine

Paracelsus was a vocal critic of existing medical practices, which he believed were ineffective and driven by profit rather than healing. His public denunciation of prominent medical authorities like Galen and Avicenna highlighted his commitment to a more empirical and nature-based approach.

Tracy V. Wilson:
"In his speech in Basel, Paracelsus threw off his hat and robe, broke his staff, and threw his sword on the ground, declaring that doctors should appear before patients with knowledge, not fancy clothes."
[18:20]

He criticized the reliance on the four humors theory, advocating instead for treatments derived from direct observation of nature and common folk remedies.

Tracy V. Wilson (Quote from Paracelsus):
"Old bloodless words, vain mouthings of ignorance, Latin sounds meaning nothing... They cling to the rich like leeches and let the poor die like flies."
[18:20]

Philosophical and Occult Beliefs

Paracelsus’s work extended beyond medicine into the realms of alchemy and hermeticism. He believed in elemental spirits—gnomes, undines, sylphs, and salamanders—and incorporated these into his medical theories, further distancing himself from his contemporaries.

Tracy V. Wilson:
"He considered things like fairies to be real and that different varieties of those fairies corresponded to the elements of earth, water, air, and fire."
[20:51]

Legacy and the Decline of the Doctrine of Signatures

After Paracelsus’s untimely death in 1541, the Doctrine of Signatures continued to influence medicine for centuries, despite increasing criticism from the scientific community. By the 19th century, it was largely discredited as more rigorous scientific methods emerged.

Tracy V. Wilson:
"The doctrine of signatures is seen today as misguided or backwards thinking, even if it was cutting-edge science of the 16th century. However, some of the associations made through it have turned out to be actually useful."
[41:31]

Modern interpretations suggest that while the doctrine was flawed, it may have inadvertently aided the discovery of effective medicinal plants by providing a memorable framework for herbalists.

Tracy V. Wilson:
"Bradley Bennett suggests that the doctrine served as a mnemonic device, helping people remember which plants could treat specific ailments."
[41:31]

Conclusion

Holly Fry and Tracy V. Wilson conclude the episode by reflecting on Paracelsus’s complex legacy. While his unorthodox methods and beliefs were often met with hostility, his emphasis on empirical observation and skepticism of established authorities paved the way for more scientific approaches in medicine.

Tracy V. Wilson:
"Paracelsus was sometimes called the Luther of doctors, and he truly shook up the medical profession. His combination of science and the occult remains intriguing, though it doesn’t align with modern scientific standards."
[37:08]

The episode underscores the importance of Paracelsus in the evolution of medical science, highlighting both his contributions and his eccentricities.

Notable Quotes

• Tracy V. Wilson:
  "The soul does not perceive the external or internal physical construction of herbs and roots, but it intuitively perceives at once their signatum."
  [29:10]

• Paracelsus (as quoted in the episode):
  "Old bloodless words, vain mouthings of ignorance, Latin sounds meaning nothing... They cling to the rich like leeches and let the poor die like flies."
  [18:20]

• Tracy V. Wilson:
  "A signature, like beauty, is in the eye of the beholder."
  [42:48]

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This episode offers a comprehensive look at Paracelsus’s role in medical history, his innovative yet controversial ideas, and the lasting impact of his work on subsequent generations. For those interested in the intersections of medicine, philosophy, and the occult, this episode provides a fascinating exploration of a man who dared to challenge the status quo.

Transcript

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[Manny]

Welcome to Stuff youf Missed in History Class. A production of iHeartRadio. Hello and welcome to the podcast. I'm Holly Fry.

[Devin]

And I'm Tracy V. Wilson.

[Manny]

This is a topic that actually came up on another show that I work on occasionally called Our Skin. And here's the thing. I was trying to do calendar math and it hurt my heart and my brain.

[Devin]

Oh, no.

[Manny]

Because I can't figure out when that one is coming out in relation to when this one will come out. Listen, I'm not the boss of the schedule on that one, so I don't know what's going on, but there's no overlap other than the mention of the doctrine of signatures and a little bit of talk about it. But it ended up being a thing where I was like, you know, we should probably talk about that because I don't know that we have. And there's some things. And then this ended up being a lot about Paracelsus because he is important in the history of medicine. He's mentioned in a lot of our previous episodes. There hasn't really been an episode focused on him. And his life was super interesting. He was a very rebellious person who was very frustrated with established medical practice and academia. And he was sometimes on the lam because of his beliefs, which is pretty fun. I love if you read biographies of him, it's like, and then he spent a period of wandering. But then other accounts will be more detailed and be like, oh, yeah, he got kicked out and then he was on the run. And then. Or not even in some cases, like we mentioned one in this episode where he was actually wanted for arrest, but in others it was just like, everybody's real sick of you, Paracelsus. You might want to get out of town. But so I ended up very much down the rabbit hole of him because he is one of the people who really, really set up this idea of signatures. He's not the first to have the idea, but he really expounded on it. He wrote a lot about it. And so it makes sense to talk about him right alongside the doctrine of signatures. So today we are going to talk about his life and work specifically as it related to the doctrine of signatures.

[Devin]

Before we humans understood the science behind how the body functioned, which, I mean, that's something we are still figuring out. But before we really had the concept of things like evidence based medicine, there was the doctrine of signatures. And that name makes it sound like a book or a tract. Of course there have been books and tracts written about it, but that's not anything physical, it's a concept. The idea is that you could intuit the things from nature that might heal a given medical problem by finding ways in which those items from the natural world resembled the ailing part of the body. So the signature of a plant in this ideology is in its physical presentation.

[Manny]

And as to where all of this began, it's almost impossible to pinpoint. We'll talk a little bit more about some theories later, but for one, this concept of a plant's appearance, giving a clue as to its possible use, kind of sprang up in multiple world cultures over the centuries. And a second problem in tracing the roots of this idea lies in the fact that this was the type of information that typically was passed down through oral tradition by people who may have been considered healers in their communities, but not necessarily doctors or any other profession that would have routinely made notes about their work. There were occasional mentions of it. Dioscorides wrote in the first century ce, Quote, the herb Scorpius resembles the tail of the scorpion and is good against his biting. That is a classic example of the type of association that was being used to identify what people believed might treat.

[Devin]

A problem in the Western world. 16th century physician Paracelsus is often invoked as perhaps not the originator of this concept, but certainly a proponent of it and also as somebody who codified it. That, like the terminology of signatures, kind of comes about in or around his lifetime. We'll kind of set the stage by talking about him and his work. Paracelsus was born Philippus Aeriolus Theophrastus Bombastus von Honheim in einsieden, Sweden, in 1493. And as a boy, he did go by the name Theophrastus. His father, Wilhelm, was a doctor and a chemist, and his mother, Elsa Ochsner, died when Theophrastus was still a young child. He and his father moved to Austria, where his father had gotten an appointment as the town physician for Villach.

[Manny]

There. Theophrastus was educated in metal mining with the intention that as he matured, he would work in an administrative role in the mining industry of Villach, Austria. So keep in mind, this education, of course, would have been a bit misguided. At the time, the idea of transmutation of base metals into gold was still considered a viable possibility. And people also believed that metals grew underground, kind of like plants. But what Theophrastus noticed was that a lot of the people who worked in the mines also had medical problems.

[Devin]

Theophrastus did not go into the mining business, although that education would come into play later. He went to the University of vienna starting in 1509 and studied math there, as well as astrology and medicine. After a year, which was considered a completion of his coursework, he moved to the University of Ferrara in Italy to get a medical degree. From the age of 14, he knew he was called to a life in medicine, and he chose the name Paracelsus around 1516, shortly after graduating. This offers an indication that he intended to build on the work of Roman physician Aulus Cornelius Celsus, who lived in the first century, both BCE and ce.

[Manny]

He also started kind of wandering Europe in search of more knowledge. And this was not entirely uncommon at the time. There had been an explosion of universities in the Middle Ages and the printing press had been invented several decades earlier. And as a consequence, this was a time when a lot of young thinkers kind of chose to sample from multiple schools to gain a broad knowledge base and also kind of seek a place that felt right to maybe settle down and start a life. Theofrastus spent time at many universities throughout Germany, Austria and Italy, but he came away finding the educations that they offered pretentious and unsatisfying. He famously wrote, I wonder how the high colleges managed to produce so many high asses.

[Devin]

Paracelsus also found schools to be pretty useless for getting an education for the medical vocation. He felt that a university setting just didn't offer all the information that a doctor would actually need in their day to day practice. So he sought out other sources of information and he came to the conclusion that he could learn more from everyday people who dealt with maladies as part of their lives than he could from academics. He mentions in his writings speaking with old wives, sorcerers, travelers, innkeepers, monks, barbers, alchemists, and even gangs of bandits to learn what practices they found to be beneficial.

[Manny]

In 1524, he returned to Vilach to visit his father before moving north to Salzburg. That was where he planned to start practicing medicine. But his plan in Salzburg got derailed by the German Peasants War. This event could be its own episode, but for the purposes of context for Paracelsus. In this uprising, peasants formed armies to fight against the aristocracy, which was having its own conflict with the Roman Catholic Church. But the moves that the aristocracy was making for its own benefit were only going to hurt the peasant class. And it would actually push them from the status of vassals, having some ownership of the land, to more of a debt, bondage, serfdom position. And given what we've said about Paracelsus already, it's probably no surprise to anyone that he sided with the peasants but the peasants were really not equipped to fight a war and the aristocracy quickly defeated them, killing an estimated 100,000 people in the process, although some estimates put that number a good bit higher. And Paracelsus survived this conflict, but because of his alliance to the peasants, there was a warrant out for his arrest and so he fled Salzburg.

[Devin]

This war came up in our episode on Guts of the Iron Hand, which I only remember just now as we are sitting here, even though that is an episode that I researched and wrote. So if you want more about that, you can go listen to the Guts of the Iron Hand episode. We'll pick up more with Paracelsus life after this uprising. After a sponsor break.

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[Robert Lamb]

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[Joe McCormick]

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[Robert Lamb]

The week's monster fact will focus on a popular cat creature, and you better believe weird house cinema will cover some kind of head scratching cat movie. So tune in August 5th through 8th for stuff to Blow your mind's Cat Week. Find us on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

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[Manny]

After fleeing Salzburg, Paracelsus lived in Strasbourg for a while before moving on to Basel, Switzerland. And in Basel, he had several successes that would help to establish his reputation as a doctor. First, he treated a man named Johan Froben for an infection in his leg that threatened that lamb's future. It was believed before Paracelsus got involved that the only real option was amputation. But Paracelsus was able to save the leg by clearing up that infection and helping it heal. It is not entirely clear how he did this.

[Devin]

Boy, am I curious, though.

[Manny]

Me too. I have a Theory we can talk about on behind the scenes, but it's not a treatment I would wish on anybody.

[Devin]

All right? Right. His next case involved a friend of Froben named Erasmus. Erasmus had an advanced case of gout, and for this, Paracelsus gave him laudanum. Some people say Paracelsus actually invented laudanum, although his exact recipe for it is unknown. It may differ from the modern definition of what laudanum is, which is a tincture composed of a 10% solution of opium powder dissolved in a high alcohol by volume spirit. Laudanum is not a cure for anything, although it is a very high dose pain reliever, so high dose that part of their symptoms include pain especially they might think they have been cured, even though laudanum doesn't cure gout. Erasmus was declared cured, and Paracelsus was soon given the job of town doctor in Basel.

[Manny]

And in that role, he quickly used his status to share his opinions on the medical practice that had preceded him and just the medical establishment. In June of 1527, he distributed handbills that he was going to give a public speech. And when that day came, Paracelsus appeared in a black robe and hat with red golden trim, carrying a staff and sword. And he had an assistant with him who was carrying two large books. So this particular day of this speech was a day when Basel traditionally had a large public bonfire as part of the celebration of the feast of St. John. That fire was part of a university event that they apparently had every year. And at this point, Paracelsus taught at the university. It fell under his duties as Basel's town physician.

[Devin]

He sort of showboated for a moment before the crowd, and then Paracelsus reportedly threw off his hat and robe, broke his staff and threw the sword on the ground, saying that a doctor should appear before patients not in fancy clothes and adornment, but with knowledge. Then he threw one of the books on the fire, saying that was Galen. A second book went onto the fire and he said, that was Avicenna. We've talked about Avicenna on the show, also called Ibn Sina back in 2014. Paracelsus then continued this very scathing critique. Quote old bloodless words, vain mouthings of ignorance, Latin sounds meaning nothing. From these books, your doctors get their Latin for diseases they know nothing about, and their Greek for diseases they never heard of. Gray bearded frauds, old wormy moth eaten sophists. Lousy pretenders with their fine clothes, their long steps, their Latin to hide their ignorance. They cling to the rich like leeches. And let the poor die like flies. When there is a real disease, they fly from it, afraid for their reputations. Paracelsus also stated that the various cures that were frequently used just caused more problems than the disease they were meant to address, and that all of this was about getting money, often from people who were being given false hope.

[Manny]

As you can imagine, this presentation did not go over well with any of his colleagues. He had, at that point, publicly sought to discredit not only his employers, but also his peers in academia. And while his push to learn from and care from the common people of the city seems very much like a feel good moment, it was also deeply rooted in his own ego. So, of course, he was correct to reject the belief put forth by Galen that the body was composed of four humors and that an imbalance in those humors was the source of disease. Like, he was rejecting things that were not founded in science, and he was extolling the virtues of looking to nature and the common people for cures. But he was also pretty clear that he understood all of that way better than anyone else possibly could.

[Devin]

Yeah, this is like such a similar attitude to, like, the wellness industry today saying, established doctors know nothing. We have all the answers.

[Manny]

Uh huh.

[Devin]

Um, like this was the same. The same thing kind of playing out centuries ago. Additionally, this meant that he considered things like fairies to be real and that different varieties of those fairies corresponded to the elements of earth, water, air, and fire, those being, respectively, gnomes, undines, sylphs, and salamanders. He explained that these elementals were soulless spirits that were living in the matrices of each element.

[Manny]

And he wrote a lot about these entities and their lifestyles. He wrote so much, and I was reviewing so much that I was, like, having a hard time picking what I wanted to share. But this tickled me. So here we go. Of gnomes, he wrote, quote, the lot of man is very hard. To hope or to wish will profit him nothing, and he must work for all he wants. But the gnomes have whatever they seek without any labor in getting or preparing it. Concerning their day and night, their sleeping and waking hours, the case is exactly the same with them as with men. Moreover, they have a sun and a firmament no less than we have. That is, the gnomes have the earth, which is their chaos. This is to them only as our atmosphere. It is not as earth to them in our sense. Hence it follows that they see through the earth just as we do through the air. And the sun shines for them through the earth as it does for us through the air, for they have the sun, the moon and the whole firmament before their eyes. So the four humors are bad, but y' all gnomes are real and we need no attention.

[Devin]

Four humors are bad, but four types of fairies are good. This whole idea of four earthly elements was grounded in alchemy. That was something that as a boy he had studied with his father and with other teachers. He also thought that ghosts were real, explaining them as sort of echoes of a human trapped on the earthly realm for a while after death. Feel like this is still a common way that people talk about ghosts. He was groundbreaking for his time, but also working with some really non scientific ideas by modern standards. He also advocated that many of the spirits that the church had characterized as bad as were just these elementals, and they were scientific. And this too ruffled a lot of feathers in academic circles. He seems to have been really at odds with just about everybody in the town who could have been considered a professional colleague.

[Manny]

So cut to 1528, by which point it was pretty clear that it was time for Paracelsus to leave Basel. He did not settle down for several years and he kept moving around, in part because people would get real tired of him. But he was also returning to the habit of his earlier years, where he kind of traveled and studied. Although this time he was not stopping in for study at universities. He instead observed real people and their medical issues. And he also, it seems, worked as or shadowed a field medic for the Venetian army. And all of this falls in line with his frequently climbing quoted line of writing. A doctor must be a traveler. Knowledge is experience.

[Devin]

During these years, he wrote about a treatment for syphilis, as well as his theory on the origin of syphilis. We know what causes syphilis today, but its exact origins on Earth are still not known. He believed that this had originated as a result of sexual intercourse between a sex worker who had gonorrhea and a person with leprosy. This belief in the origin of syphilis probably explains his proposal to treat syphilis with mercury, which was also being used to treat leprosy. Paracelsus wrote about this treatment in 1530, and it was used for centuries. This is probably because it did appear in some cases to eliminate the disease. But modern medical experts and historians suspect that this was actually the result of observing syphilis going into a dormant period, which is something that it naturally does. And there were certainly patients who died. Their deaths were chalked up to the disease. But it's just as Likely that they died of mercury poisoning.

[Manny]

In his traveling years, Paracelsus also wrote what would become probably his most well known work. This was Der Grossen Wundertzne. That's a great surgery book. I probably butchered that German that was published in 1536. And this was based on his time working with military units and treating wounds, as well as observing how soldiers manage their own care.

[Devin]

And then we get to his writings on hermetic chemistry. Hermeticism references the writings of a man the Greeks called Hermes Trismegistos, the Egyptian God Thoth. Those writings examine astrology, the occult, theology and philosophy. And there's a whole section of Paracelsus's hermetic chemistry writings called concerning the Signature of Natural Things.

[Manny]

So this writing is not only about medicine, it talks about what the signature of things is. Paracelsus explained that in his view, there are only three signators. Man, Archeus, and the stars. And archaeos is a term that he used to describe the vital principle that's responsible for the growth and continuation of all living things. So in a very boiled down sense, that's what he's calling the natural world. And there's a lot of talk in this writing about the ways that people can choose to signify themselves, I. E. How they present publicly through dress and presentation. And all of this really is him setting up this idea that you can tell a lot about a person or a thing by simply looking at it. This is a problem. As an example, black eyes not only denote a healthy constitution, but also, for the most part, a constant mind, free from doubt and fear, healthy and hearty, truthful and loving virtue. Gray eyes are the sign of a crafty man, ambiguous and inconsistent. Weak eyes denote good counsels, clever and profound deliberations, and so on. Bright eyes, which turn up, down and to both sides, denote a false clever man who cannot be deceived, faithless, shirking work, desirous of ease, seeking to gain his livelihood, and laziness by gambling, usury, impurity, theft, and the like. Obviously this is nonsensical. And there are many other ways in which Paracelsus believed that a person's appearance could tell you about their personality and behavior.

[Devin]

He also wrote at length about chiromancy or palm reading, as though it were a hard science, and the planets and the metals that they were associated with, and even necromancy. And then he gets to the curatives. One, for example, is a tincture made from urine, and there's a full recipe. Take old urine poured away from its Deposit several cups of it in which dissolve 3 handfuls of ground salt. When you have strained it, boil it and skim it carefully. In this again dissolve a handful of bruised vitriol, that's sulfuric acid, with 2 or 3 ounces of bruised salt ammoniac, and then carefully skim again with this liquid, imbibe some filings and boil it until it can be pulverized. The dust thus produced reverberate over a powerful fire, continually stirring it with an iron rod until it changes from its own color to another, and at last to the hues of most brilliant violet. From this you can easily, with spirits of wine or distilled acetum, draw off the tincture. And when it is extracted by separation of the elements, you will collect what remains at the bottom of the glass by means whereof you will be able to produce wondrous effects both within and without the body.

[Manny]

Throughout his various writings on what he calls signatures, Paracelsus explains that the earth purposely makes plants resemble other so that humans can see the correct plant to treat their illnesses, but that they don't even necessarily need to see those things, because our intuition already knows this truth. Without consciously seeing the signature. He wrote, quote, the soul does not perceive the external or internal physical construction of herbs and roots, but it intuitively perceives at once their signatum. His idea, gleaned from speaking with everyday people and which was expounded upon by scientists that followed, was that, like if you find a plant with a kidney shaped leaf, that it would be useful in treating ailments of the kidneys.

[Devin]

We should note though, that this line of treatment as outlined by Paracelsus, is often a bit more indirect than simply consuming a plant that you see, because he loved his lab work, sometimes he worked things into a tincture, such as that long process with urine that we just described. He treated plague in a similar way, using minute amounts of the patient's excrement and preparing a medicine for them. Allegedly, he cured a number of people this way.

[Manny]

Yeah, I would like to see the notes on that. Paracelsus's end is actually a little bit of a mystery. We know that he died in Salzburg, Germany on September 24, 1541, at the age of 48. But exactly how that happened has been relayed inconsistently in various accounts through the years. However it happened, it does appear that it was relatively sudden. So in one account, he is said to have died in the kitchen of an inn that he was staying at. Sometimes references that he was sitting on a bench near the stove and just passed away. Another also mentions the Inn, which is the White Horse Inn, and that account says he died in his bed there after a sudden illness that came on that he had for a few days. And then there is another version that can kind of build on these two scenarios, suggesting that the suddenness of his death or illness was because he had perhaps been poisoned by an assassin hired by a fellow physician or group of physicians who did not like Paracelsus shakeup of their profession.

[Devin]

We will talk about the Doctrine of Signatures after Paracelsus in just a moment, but first we'll hear from the sponsors that keep the show going.

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[Noah]

A foot washed up, A shoe with some bones in it. They had no idea who it was.

[Devin]

Most everything was burned up pretty good from the fire that not a whole lot was salvageable.

[Robert]

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[Manny]

He never thought he was going to.

[Noah]

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[Manny]

My computer screen, I was just like, ah, gotcha.

[Robert]

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[Robert Lamb]

Hey, this is Robert Lamb and this.

[Joe McCormick]

Is Joe McCormick and we're the hosts of the Stuff to Blow youw Mind podcast, we've got an exciting week ahead for you on Stuff to Blow youw Mind. It's Cat Week. That's right. To coincide with International cat Day on August 8th, we're dedicating every episode in the Stuff to Blow youw Mind podcast feed to your cute, mysterious feline companions. So tune in for core Stuff to Blow youw Mind episodes on the earliest archaeological evidence for domesticated cats and the folkloric cats of the British Isles.

[Robert Lamb]

The week's Monster Fact will focus on a popular cat creature and you better believe weird house cinema will cover some kind of head scratching cat movie. So tune in August 5th through 8th for stuff to Blow your Mind's Cat week. Find us on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

[Noah]

Imagine that you're on an airplane and all of a sudden you hear this.

[Manny]

Attention passengers. The pilot is having an emergency and we need someone, anyone to land this plane.

[Noah]

Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control. And they're saying like, okay, pull this, until this, pull that, turn this. It's just I can do my eyes closed. I'm Manny.

[Devin]

I'm Noah, this is Devin.

[Noah]

And on our new show, no Such Thing, we get to the bottom of questions like these. Join us as we talk to the leading expert on overconfidence.

[Robert Lamb]

Those who lack expertise lack the expertise they need to recognize that they lack expertise.

[Noah]

And then as we try the whole thing out for real. Wait, what? Oh, that's the Runway. I'm looking at this thing.

[Manny]

See?

[Noah]

Listen to no Such thing on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

[Manny]

Paracelsus death was hard to hardly the end of his work. His writings on signatures had a life of their own. And also he did not call it the Doctrine of Signatures. It picked up that name several decades later when other people were writing about it. But the other thing is, he had written additional texts that got published posthumously. And his combination of science and the occult has remained alluring for a great many readers in the centuries since he died. Even people today, I find them alluring because they're interesting, but I don't think they're science. Keep in mind too that this time of Paracelsus life was really a big moment in human history, particularly in Europe. So at the same time that Theophrastus Paracelsus was exploring the world of knowledge. The earliest voyages of Spain to North America were underway and the beginning of colonization by Europeans. Da Vinci was painting his masterpieces. Michelangelo was just starting his career. And Martin Luther was about to start a big uproar in challenging the Catholic Church. Paracelsus was sometimes called the Luther of doctors. And he hated it because he was like, everybody hates him and wants to kill him. Please don't say that about me. So it is important, as we talk about this to contextualize the work of Paracelsus in a world that was undergoing a lot of other massive changes.

[Devin]

We know that he was not the only person who believed in this idea of the doctrine of signatures. But as we mentioned earlier, the origin of this concept is unknown. There are a number of ideas related to Paracelsus. Use of the writings of Hermes, Trismegistus. There's one school of thought that the doctrine of signatures originated in Egypt. There's also a theory that China is really where these concepts began and that as trade routes were established with Europe in the Middle Ages, these ideas spread quickly. And there's a whole other approach that takes the position that we as humans just want to apply some sort of pattern recognition to the world around us in order to understand it, regardless of where we come from, geographically or culturally.

[Manny]

We're going to talk about that reference to Chinese origins again in just a minute. But in the west, all of this kind of got rolled up under a religious ideology, suggesting that, of course, God created all of these clues in the way things in the natural world were shaped to lead us to the right treatments. But there are, of course, problems inherent in that. For one, it hinges on the idea that everyone believes in the same God. Doesn't account for religions where there would be multiple gods. Who's responsible for making plants shaped like organs. For another, it also puts humankind at the center of everything in the universe, as though all of these things were created just for us.

[Devin]

Putting all of that aside, what if two physicians were to disagree on what signature a plant had? That was part of the early criticism of the doctrine of signatures, which started really almost as soon as Paracelsus had started writing his long explanations of it. Flemish physician and botanist Ramberto Doyne, sometimes called the father of botany, wrote of the doctrine just a couple of decades after Paracelsus Else's passing, saying, quote, it is so changeable and uncertain that it seems absolutely unworthy of acceptance. Others followed suit over the years, including the father of homeopathy, Samuel Hahnemann.

[Manny]

The doctrine of signatures persisted, though, as a guiding tool for medicine for a long time. This excerpt is from the British medical journal in 1873, and it denounces it as backward, but the ongoing fascination with it is apparent. Quote According to M. Gubler's recent report to the Academy of Medicine in Paris on the Chinese Materia medica, the belief in the specific action of drugs seems to have strongly influenced medical practice in China, as it did but lately that of Europe. Besides, the Chinese believe, as the Europeans did in the Middle Ages, that the appearance of a substance will give a clue to the services it may render to man, that is the doctrine of signatures. Thus the luciole is recommended for affections of the visual organs. A madder having a red root is given for amenorrhea. Polygonum tinctorium, which yields indigo, is reputed efficacious for eruptive fevers. The reniform fruit of the Katsura chinensis is said to possess aphrodisiac properties, while ginseng, with its bifurcated root resembling the legs of a man, is looked upon as restoring virile powers to the sick and aged. Considerations of the same kind are doubtless the foundations of the reputation of the Cordyceps sinensis as exciting the genital organs that of the Barden's parviflora as infallible in making the nails grow. These are strange illusions, but they merit indulgence from those whose ancestors administered the lungwort to cure thesis, the gromwell to cure, the gravel and the carrot for the jaundice.

[Devin]

As more rigorous methods of testing substances and recording treatment efficacy evolved, the doctrine of signatures fell out of favor because so many of the claims that had been made by its followers were really proven false. For the most part, the doctrine of signatures is seen today as the misguided or backwards thinking, even if it was cutting edge science of the 16th century. But then there are instances where some of the associations made through it have turned out to actually be useful. Is there a way to reconcile that?

[Manny]

Some people think so. In a 2007 article in Economic Botany, Bradley Bennett suggests a possible reinterpretation of the doctrine of signatures, writing quote in traditional cultures, plant knowledge is effectively passed from one generation to the next through observation and oral tradition. The doctor of signatures should be re evaluated with respect to 1 its role in the discovery of medicinal plants, 2 post hoc attribution of signatures, 3 the nature of signatures and 4 its role as a mnemonic. So this idea is that a plant that was found to have a medicinal benefit then could have the association of characteristics related to the illness it was treating applied to the plant retroactively to sort of help people remember. Oh, that's the plant that helps me with this thing. Bennett continues later in that write up quote, a signature, like beauty, is in the eye of the beholder. In 1628, Guy de la Bras noted that it was easy to imagine any resemblance between a plant and an animal that happened to be convenient. Bennett also notes later in that same paper that quote, seeing a particular signature often requires a vivid imagination.

[Devin]

As a postscript, we really haven't included a lot in the way of examples in this episod that look like a human organ. And then people might use it to treat an illness related to that organ that's on purpose because there are still people who want to apply this method. When I was in massage school, I had an herbal medicine teacher who brought it up repeatedly. We are just not gonna feed into that.

[Manny]

Yeah, I also in an age when things get scrubbed and reported to people as though it's real through AI out of context, we're not going to offer anything that might help that right? Because I don't want anybody to get hurt. So that is the doctrine of signatures and paracelsus for today. I have sewing email which makes me happy in my heart. This email is from Sarah and it makes me so happy and it involves one of the cutest dogs in the world. Sarah writes, I am in my 70s. I started sewing when I was probably 11. Sewed lots of clothes for myself as a teenager, including a pantsuit alongside my best friend sewing hers. We wore them to see the monkeys at the Hollywood bowl just in case we might meet them. I sewed my wedding dress and lots of clothes for my kids. I loved the folkwear patterns at that time. That was a brand by the way. When my creative daughter showed interest in sewing, she eschewed patterns. She created all kinds of interesting things including complex wallets and purses. Just making them up for herself. So fast forward to the present. I was so excited to hear your shows on sewing patterns. They were fascinating. And then a couple of days later my daughter, her wife and I started watching the Great British Sewing Bee and guess what they talked about in the first episode? Sewing pattern history. I was yelping with delight repeatedly while watching the segment. So fun when worlds collide like that and make sparkles. Thank you for a fascinating topic. Well covered. This is Luna, our rescue from Taiwan dog. She is a Taiwanese mountain dog cross and the sweetest dog ever. She adores her family and worries until we all six of us in the house are back home. This dog is so cute. It's a sweet little black pup and she has white sprinkles on her paws and oh, she's really, really cute and she's hugging a lambie and it's really adorable. And then there's a bonus kitty. This is Mercury, one of our three Humane Society kitties. He is pretty wild and so much fun. He's also beautiful. This also worked out because Mercury came up in the episode and I'm gonna talk about it in behind the Scenes on Friday.

[Devin]

Okay.

[Manny]

We are so thankful, Sarah, for you sharing this. I'm glad you like the sewing patterns episode. I always worry when it's very much in my super niche interests that it might not be for everyone, but I'm glad it's for some people. If you would like to write to us, you can do so at history [e-mail] you can also subscribe to the show on the iheartradio app or wherever you listen to your favorite shows.

[Devin]

Stuff youf Missed in History Class is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

[Robert]

Every case that is a cold case that has DNA right now in a backlog will be identified in our lifetime on the new podcast, America's Crime Lab. Every case has a story to tell, and the DNA holds the truth.

[Manny]

He never thought he was going to.

[Noah]

Get caught, and I just looked at my computer screen. I was just like, ah, gotcha.

[Manny]

This technology's already solving so many cases.

[Robert]

Listen to America's Crime Lab on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

[Noah]

Why are TSA rules so confusing?

[Devin]

You got a hoodie on. Take it off.

[Noah]

I'm Manny. I'm Noah.

[Devin]

This is Devin.

[Noah]

And we're best friends in German journalists with a new podcast called no Such Thing where we get to the bottom of questions like that. Why are you screaming? I can't expect what to do now. If the rule was the same, go off on me. I deserve it, you know. Lock him up. Listen to no Such thing on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

[Manny]

No Such Thing.

[Robert Lamb]

Hey, this is Robert Lamb and this.

[Joe McCormick]

Is Joe McCormick, and we're the hosts of the Stuff to Blow your Mind podcast. We've got an exciting week ahead for you on Stuff to Blow your Mind. It's Cat Week. That's right. To coincide With International cat Day on August 8th, we're dedicating every episode in the Stuff to Blow youw Mind podcast feed to your cute, mysterious feline companions. So tune in for core Stuff to Blow youw Mind episodes on the earliest archaeological evidence for domesticated cats and the folkloric cats of the British Isles.

[Robert Lamb]

The week's Monster Fact will focus on a popular cat creature and you better believe weird house cinema will cover some kind of of head scratching cat movie. So tune in August 5th through 8th for stuff to blow your mind's Cat Week. Find us on the iHeartRadio app, Apple Podcasts or wherever you get your podcasts.

[Devin]

In 1920, a magazine article announced something incredible. Two young girls had photographed real fairies.

[Robert]

But even more incredible, that article was.

[Devin]

Written written by Sir Arthur Conan Doyle, the man who invented Sherlock Holmes. How did he fall for that? Hoax is a new podcast from me, Dana Schwartz, the host of Noble Blood, and me, Lizzy Logan. Every episode we'll explore one of the most audacious and ambitious tricks in history and try to answer the question why we believe what we believe.

[Manny]

Listen to Hoax on the iHeartRadio app.

[Robert]

Apple Podcasts, or wherever you get your podcasts.

[Devin]

Passage this is an iHeart podcast.