Unexplainable - Who are we to fight the alchemy?

Episode Date: March 16, 2026

Many alchemical texts are full of bizarre, metaphorical language. But what if there's interesting science hiding behind some of those metaphors? Guest: Lawrence Principe, professor of the history of science and professor of chemistry at Johns Hopkins University For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠[e-mail]⁠⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

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BetMGM operates pursuant to an operating agreement with Eye Gaming Ontario. Lawrence Prince Be has been interested in alchemy for a while now. Many years ago, and I won't say how many, when I was in high school, I was rooting about in the public library. Now, the usual reason I did this was because I was very interested in chemistry, often very interested in making fireworks and that sort of thing that teenagers like to do. And in this particular visit, I noticed that there were books before I got to chemistry, on the history of chemistry. And there was a book I remember called The Arts of the Alchemists.

And I took it down off the shelf and I started thumbing through it and it was filled with beautiful images and some facsimile pages of alchemical manuscripts. And at that point, I began to think, well, wow, what were they actually doing? Now, after that discovery, he did go on to make some fireworks. Oh, yes. I spent quite a great deal of time doing it. doing that when I was a younger person. Yes, and I still even have all my fingers and toes.

But ultimately, the question of what the alchemists were actually doing stuck with him. In fact, he has devoted a sizable chunk of his career to answering it. He's now a professor of the history of science and a professor of chemistry at Johns Hopkins. And over the last few decades, he has helped turn our understanding of alchemy kind of on its head. So before I read about Lawrence's work, I thought alchemists were nothing more than either medieval quacks or single-minded obsessives who wrote fanciful books about turning lead into gold and achieving immortality. I thought they were a joke, essentially. And I thought this because that's been the cultural narrative about alchemy for a long time. But now Lawrence is one of several historians of science who've been rewriting that narrative.

They have been recreating old alchemist experiments in modern day labs. And by doing this historical recreation, they have pieced together a new story, a story that is forcing people like me to reevaluate what I thought I knew, not just about alchemists, but also about the history of chemistry itself. So this is unexplainable. I'm Bird Pinkerton. And today on the show, what were the alchemists actually doing? Researchers like Lawrence don't have all the answers, but what they are learning is kind of transmuting alchemy from a joke into a fascinating chapter in the history of science.

Okay, let's start with some basics, like what actually is alchemy. Yeah, that's actually a more difficult question than it sounds. Turns out, alchemy has a long history that stretches back millennia. And for a lot of that history, some of what people refer to as alchemy sounds a lot like what we might call chemistry, because alchemists weren't always solely focused on making gold. It was one of the major goals of the alchemists, but it wasn't all that they did. They were interested as well in making medicines, for example, improved pharmaceuticals, but a whole range of sort of quotidian substances like cosmetics, perfumes, alcoholic drinks, metal alloys, alloys, all these sorts of things, dyes and pigments. When Lawrence was starting out, though, he was reading through the work of European alchemists

who were trying to make the philosopher stone, so the substance that was thought to transmute metals and also sometimes extend life. Basically, the kind of alchemy you read about in literary fiction that seems like a pointless pursuit, right, or a whole lot of nonsense. And at least part of the reason that people have spent so much time thinking this kind of of alchemy is nonsense, is that if you read through alchemical books, a lot of them look like a bunch of nonsense. They are full of riddles and metaphorical language and stuff like, Take our fiery dragon that hides the magical steel in its belly with our magnet and mix

them with torrid Vulcan. This will be easily done if Saturn beholds himself in the mirror of Mars. Vence has made our chameleon, our chaos. Well, just try to take that into the lab and do something with it. This language is, it turns out, intentionally confusing. Alchemists didn't necessarily want everyone to understand their books. First of all, if you think you're close to the way of making gold from cheap substances, you don't really want everybody else to know about it.

So you might write stuff in weird, coded language. Moreover, alchemy was actually illegal in terms of the transmutation of base metals into gold. in a number of countries, mostly because people were afraid that, oh, what if this guy in his cellar starts making all this gold? Well, then the value of gold becomes zero because you can make it,

and your entire economy and political stability goes out the window. These various bands didn't stop people from doing alchemy, but, again, they meant that alchemical writing was often bizarre and full-fuscary. of metaphors, especially as you got to the late 14th century, 15th century, and beyond. And once you have that kind of metaphorical language, people just sort of go crazy with it. So instead of saying this material and that material, they'll say the Red King and the White Queen, the wolf, the lion that devours the sun, and so forth. And instead of describing

anything that could possibly seem to be like a chemical formula, let's say, they become come dream sequences or metaphorical stories. You know, I fell asleep one day and I saw a king come to take a bath and he took off his clothes and he got into the water and he melted away and blah, blah, blah, and all this sort of very rich, extravagant, really bizarre kind of language. Your fiery dragons and your Saturns beholding themselves in the mirrors of Mars. And so you can see why it is that alchemy, until very real, you know, recently, in terms of historical understanding, has simply not been understood, because it just

looks so weird. And listen, if I were a historian, I too would probably not read through something that sounded like the inspiration for Alice in Wonderland and think it looked like solid science. So it's maybe not surprising that there were a lot of interpretations that argued that alchemy was something else. There were 19th century writers who thought that the practice was more about transforming the self than about transforming real things in the laboratory, with one author saying, you know,

mercury in an alchemical text could be read as a metaphor for a clear conscience, for example. Or in the 20th century, Carl Jung reinterpreted alchemy as a kind of psychological phenomenon. So when I started trying to learn about alchemy in the late 70s and early 80s, I did not have a lot of books that helped. Still, there were people who were curious about whether, some alchemists might have been doing something non-metaphorical, and young Lawrence Princepe was one of those people. He enjoyed chemistry. He knew enough to make his own fireworks safely. And in some of these authors' private and even public writings, there were things that looked

less like fanciful metaphors and more like a series of instructions. So we figured one way to figure out if any of these texts had real practical advice, or if they were all just imagery, was to see if he could follow the instructions and produce results. So when he went off to college, that's what he tried to do. I was extremely fortunate to have chosen the University of Delaware to go to as an undergraduate. And I happened to mention my interest to one of the faculty there, and he said, oh, let me check on something and get back to you. Well, it turned out the university had purchased a huge collection of books in the history of science,

from an Italian chemical engineer, as I recall. And this faculty member actually got me access to them. Well, I couldn't have been more happy at that point having free run of this amazing collection of alchemical and early chemical books. And to make it even better, the chemistry department itself actually let me use some unused student laboratories

to try to replicate these processes. He selected one specific text written by a pretty famous alchemist. A text by a supposed Benedictine monk who went under the name of Basilius Valentinas, which is a fake name if anyone's ever heard one, a text written in 1604 on the properties and the preparations of the element antimony. Antimony is a brittle, silverish, toxic metalloid.

that makes an appearance in a lot of different texts, including this one. I chose that document in particular because it was unusually clear. It did not have the sort of wild metaphors. It seemed at least to have what were rather straightforward recipes. And for his recreation, Lawrence picked instructions that the book claimed were simple, this way of making something called a glass of antimony, which was basically taking anemone, manipulating it in specific ways

until you got kind of riddle golden glass. So young undergrad Lawrence got some antimony and got to work. All right, well, I started feeling really bad about this because the author says, well, just because I'm being complete, I'm going to tell you how to make this, but everybody knows how to make it.

Yeah, well, I try for months to make it, and it never worked. He was following the instructions and getting gunk, not glass. Not the best sign if you're trying to entertain the idea that these old texts from the 1600s describe legitimate experiments. You don't immediately think, well, there's something wrong with me. You probably think there's something wrong with the author. But Lawrence did not write off Basil Valentine because he figured his experiment was not actually a perfect recreation.

He was using Bunsenburners and other modern equipment and antimony that came from a chemical supplier, not exactly what Basil had access to back in the day. Maybe something about his modern tools was throwing things off. And so he experimented a little bit. He went to a mineral shop, for example, to try and get antimony in a form that was closer to what Basil would have had. I even tried to get it from Hungary, or what was Hungary in Basil Valentine's Day, to see if I could get something that was quite similar. What he eventually figured out was that Basil was probably working with something that had some impurities in it, like sand. and that probably would have added some silica to the mix.

And so he tried things again, but this time was some silica added. And you just need about 2% of silica, and wow, it becomes a beautiful, transparent glass. So it was a matter of the impurity that was in the original material. He'd done it. He had shown that this recipe, at least, was a real set of instructions that he could follow in the present day. I was exhilarated by this. People have criticized alchemical writers for reporting imaginary effects or just making things up or being sloppy workers. But my argument was maybe we need to just look a little bit closer and give these texts enough free space and enough time to justify themselves by looking more deeply, by being less judgmental and trying to get into the,

mindset as much as is possible of the original authors. And that is, after all, what historians are trying to do. This was a victory, obviously. But it wasn't the biggest victory. Because, yes, Florence had successfully done an experimental recreation from an alchemist book. But it was for a pretty simple glass experiment. And there's nothing in modern chemistry that suggests you can't make glass. So he started to wonder about the wackier stuff that alchemists were writing about,

like the weird metaphor language and the philosopher's stone. When you've got something like the philosopher's stone that's supposed to turn one element into another that modern chemistry tells us shouldn't happen, then you're getting a little bit deeper into the thick of things, I think. I think so too. So after the break, we will go deeper into the thick of things. It's all about you. And when you fly with Virgin Atlantic in their upper class cabin, they take the VIP treatment to the next level.

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making glass published by an alchemist back in the 1600s was, in fact, a legitimate recipe. But he still had questions, especially about the parts of alchemical texts that were more fanciful or more weird. What I was trying to do was to figure out, well, why did people believe that they were able to transmute base metals into gold? what made them write these texts with often the wild imagery? What's really going on there? He started working with the text of a 17th century, a chemical author.

His real name was George Starkey. He was born in Bermuda in 1628. He went to England, and he started circulating or writing texts under the pseudonym of Ironias Philolethes, which is Greek for the peaceful lover of truth. That's such a difference from George Starkey. Yeah. So, yeah, Iranias at Philalathes is really George. George was interesting to Lawrence because in his public work,

he was as metaphorical and flowery as the next guy. But in his private letters and his lab notebooks, his instructions were clearer and followable. And he talked a lot about his theories about alchemy. And one of his theoretical, ideas is that if you want to make gold, he uses a sort of agricultural metaphor, that gold has within itself a seed, and if you can find the right kind of metallic water to cause it to grow, you should be able to make more gold, just like you take one grain of wheat, you put it in the ground, you get more wheat back. So it's this agricultural metaphor. Apparently, there was a school of alchemical thought that believed that just like there is a seed of an apple inside an apple, there's also a seed of gold inside of gold, and that you could use the right kind of mercury to free that seed, which would result in a philosopher's stone that could change other stuff also into gold. So in this vein, one of Georgia's projects was to make this special philosophical mercury.

He claimed that you could make a particular kind of mercury, quicksilver, right? prepared in a special kind of way, that when mixed with gold and heated in a flask, would, as he calls it, vegetate. So this sounds extraordinarily unlikely. As a 21st century chemist, Lawrence was pretty skeptical that Mercury was going to do anything that you would describe as vegetating.

But he did have these rough instructions from George about how to make this happen. So he took some mercury and tried to do a version of what George did. Mixed it up with a bit of gold, put it in a flask, sealed it up, and started heating it. Again, Lawrence works in a modern lab, so he was not exactly replicating all the steps, like because he was using mercury, which is toxic. He was working under a ventilation hood, for example. But he had the substance sealed in a flask.

What's called the philosophical egg, a round bottom flask with a very long neck, that you put the ingredient in, and then you seal. And I had it buried in a sandbath in a thermostat. controlled heating mantle. He doesn't give us a correct degree of heat that has to be added, and so it took several weeks, and it just sat there as sort of a gray, slightly bubbly mass. So what I started doing is I started increasing the heat very slightly every few days before I went home. And one morning, I went in, took the flask up out of the sand,

And what the night before had been an amorphous mass of sort of gray, slimy stuff, there was a beautiful, glittering silver tree inside the flask. Well, that's sort of the result I had. I put it back in the sandbath. I sat down in my desk and sat there for several minutes quite concerned that I had actually lost my mind. Well, what had been just at the very bottom of the flask had grown upwards to fill the entire flask with a trunk and what we would call dendritic growths of a brilliant silver color. What? Yes, I have photos.

I've even published photos of that. Now, this does not mean that modern chemistry is wrong or that either mercury or gold grows like a tree. But the mercury in the flask did take a shape that looks tree-like. And so suddenly, George's vegetative language was beginning to make more sense to Lawrence, which is one really clear thing that experimental reconstruction can give a historian like him. So when they talk about this bizarre metaphorical description, it's not necessarily just their imagination or just a series of literary or metaphorical images. it actually, in some cases, has this concrete visual experience behind it.

Part of the reason I study this is why does alchemy persist so long? Well, I think that they were actually seeing remarkable things, maybe not the actual transmutation of lead into real gold. Nevertheless, imagine just for a second, if I, as a late 20th, early 21st century chemist, was absolutely shocked by this and thought that I had lost my mind, what would that have done to a 17th century alchemist who is convinced that a vegetative theory of the growth of metals is the right explanation? He would surely have said, wow, it really works. I'm going to work twice as hard to take this on to the next steps of making the

philosopher's stone, because I've seen this amazing thing. Based on his work so far, Lawrence has developed a kind of hypothesis that he's exploring. So his idea here is that the early parts of some of these texts, the first few steps, they're more like this tree of mercury situation. They're doable, practical experiments. But then as the text move on, he thinks they become more hypothetical. Experience transitions to expectation. I've got a theory of how this is supposed to go. I've seen it work this far.

What should happen next as a kind of extrapolation are the next few steps. I haven't gotten them to work, but here's the way they should work. And then a lot of these books end with the description of the philosopher's stone that he thinks is just copied from a other. older books, so not drawn from personal experience. It's kind of like a description of what they're all working towards or how they will know that they got things right. That's my working hypothesis right now.

How many alchemical texts of the thousands that are out there this actually works with? I can't say, but I can cite several where it does seem to work pretty darn well. Is there any part of you that's like the first few steps don't seem to be metaphorical, maybe they were just making philosopher stones. Oh, I often wish that. I did have the former dean of my university once come by and say, wow, if I can't balance the budget, I'm going to be coming to your lab for some help. So there's still some imagination at work in alchemical texts,

but Lawrence and other historians like him have shown that there's also some real stuff to be found as well, stuff that's grounded in repeatable experimentation. And this new perspective has also changed how Lawrence and others look at some of the early figures of the scientific revolution. Isaac Newton studied alchemy, for example, as did Robert Boyle, a leading light in early modern chemistry. Robert Boyle certainly knew his alchemical literature. He depended upon some alchemical writers. In fact, our friend George Starkey that I mentioned to you was school tutored essentially in the practice of chemistry by George Starkey. What?

They knew each other? Oh, yes. Robert Boyle, in fact, knew about the vegetative theory of mercury. Yes. Starkey entrusted him with the secret of how to do that. And he spent the next 40 years of his life trying to get it to. completion. If you think alchemy is total nonsense, that might seem like a stain on Boyle's reputation. But if you've redone the experiment and seen that this mercury tree stuff was doable

chemistry, then maybe it seems less out of character. People have sort of imagined there to be some great discontinuity in the development of chemistry or in the development of the sciences, with what I like to refer to as the arrogance of the present, thinking that, that old people were dumb and look here, the light dawns suddenly, and now we're modern. And we just see that this is just not true. And in fact, the truth of the matter is much more interesting to see this gradual accumulation of information, the refining of ideas, sometimes the discarding of theories in favor of a new one, but that's a gradual process that happens over time. And I think certainly in the case of chemistry, this is the case.

Lawrence is not the only person working in this space. And in the time since he and his partner in Reconstruction, Bill Newman, started publishing about alchemy, the field's gone through kind of a revolution. One of the things that I am shocked by is that now alchemy has dozens and dozens of people, some absolutely astonishing younger scholars as well, working on it. So it's become a hot topic in a sense. The other thing that I find equally surprising is that this experimental reproduction of chemical processes or early processes as a tool, as a historical tool in the history of science, has also become now suddenly mainstream. If not mainstream, then at least more popular. And experimental recreations can't give researchers everything, right? even if Florence recreated every detail of a medieval lab perfectly,

which he doesn't try to do, he's always going to be a 21st century chemist, operating in a 21st century framework. Clearly, when I'm looking at something, anything, it doesn't matter. When I'm looking out the window, I am interpreting it through all sorts of lenses that have been created by the social, political, emotional, religious context

of 2026. And my historical actors, in the same way, have their own mental landscape constructed by 1354 or 1661. So there will always be limits to what anyone can learn about the past by reconstructing it. But still, when I think about the experimental tradition in science, right, the idea that you try things to see what shakes out, I think it's really fitting that the history of science is incorporating that approach to. And maybe it's not surprising that some big field-changing ideas have come out of the attempt.

If you would like to read more about alchemy, Lawrence Prince Pais's book, The Secrets of Alchemy, is a great place to start. It has a lot of information about the history of alchemy that we couldn't fit into this episode, and a great section about how alchemy got such a terrible reputation. Also, if you want to read more about turning lead into gold, in doing the research for this episode, I learned that physicists have actually turned a very small amount of lead into some very short-lived gold by using a particle accelerator. So I will link to a nature article about that in the transcript.

This episode was produced by me, Bird Pinkerton. It was transmuted into, if not gold, than at least a better version of itself by my editor. Joanna Salataroff. Joe Plourd, did the mixing and the sound design. Noam Hassanfeld does our music. Melissa Hirsch, checks our facts. Jorge Just, Meredith Hodnott, Julia Longoria, Sally Helm, and Amy Padula are the fact that large raindrops are shaped like hamburger buns. And my thanks to Jennifer Rampling, Angela Krieger and Bruce Moran for speaking to me for this episode and helping me better understand both alchemy and the history of science. Thanks also to Matthew Jordan. for sending me down this rabbit hole to begin with. If you have thoughts about alchemy or things about the history of science you think we should explore,

please email us. We are at Unexplanable at Vox.com. We are always open to your ideas and we really love hearing about your research as well. If you would like to support this show and the journalism that Vox does, we would love it if you would become a member. It is very easy to do.

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and we will be back very soon with another episode about everything that we do not yet know.