In his 1686 Prin­cip­ia Math­e­mat­i­ca, Isaac New­ton elab­o­rat­ed not only his famous Law of Grav­i­ty, but also his Three Laws of Motion, set­ting a cen­turies-long trend for sci­en­tif­ic three-law sets. Newton’s third law has by far proven his most pop­u­lar: “every action has an equal and oppo­site reac­tion.” In Arthur C. Clarke’s 20th cen­tu­ry Three Laws, the third has also attained wide cul­tur­al sig­nif­i­cance. No doubt you’ve heard it: “Any suf­fi­cient­ly advanced tech­nol­o­gy is indis­tin­guish­able from mag­ic.”

Clarke’s third law gets invoked in dis­cus­sions of the so-called “demar­ca­tion prob­lem,” that is, of the bound­aries between sci­ence and pseu­do­science. It also comes up, of course, in sci­ence fic­tion forums, where peo­ple refer to Ted Chiang’s suc­cinct inter­pre­ta­tion: “If you can mass-pro­duce it, it’s sci­ence, and if you can’t, it’s mag­ic.” This makes sense, giv­en the cen­tral impor­tance the sci­ences place on repro­ducibil­i­ty. But in Newton’s pre-indus­tri­al age, the dis­tinc­tions between sci­ence and mag­ic were much blur­ri­er than they are now.

New­ton was an ear­ly fel­low of the British Roy­al Soci­ety, which cod­i­fied repeat­able exper­i­ment and demon­stra­tion with their mot­to, “Noth­ing in words,” and pub­lished the Prin­cip­ia. He lat­er served as the Society’s pres­i­dent for over twen­ty years. But even as the fore­most rep­re­sen­ta­tive of ear­ly mod­ern physics—what Edward Dol­nick called “the clock­work uni­verse”—New­ton held some very strange reli­gious and mag­i­cal beliefs that we would point to today as exam­ples of super­sti­tion and pseu­do­science.

In 1704, for exam­ple, the year after he became Roy­al Soci­ety pres­i­dent, New­ton used cer­tain eso­teric for­mu­lae to cal­cu­late the end of the world, in keep­ing with his long-stand­ing study of apoc­a­lyp­tic prophe­cy. What’s more, the revered math­e­mati­cian and physi­cist prac­ticed the medieval art of alche­my, the attempt to turn base met­als into gold by means of an occult object called the “Philosopher’s stone.” By Newton’s time, many alchemists believed the stone to be a mag­i­cal sub­stance com­posed in part of “soph­ick mer­cury.” In the late 1600s, New­ton copied out a recipe for such stuff from a text by Amer­i­can-born alchemist George Starkey, writ­ing his own notes on the back of the doc­u­ment.

You can see the “soph­ick mer­cury” for­mu­la in Newton’s hand at the top. The recipe con­tains, in part, “Fiery Drag­on, some Doves of Diana, and at least sev­en Eagles of mer­cury,” notes Michael Greshko at Nation­al Geo­graph­ic. New­ton’s alchem­i­cal texts detail what has long been “dis­missed as mys­ti­cal pseu­do­science full of fan­ci­ful, dis­cred­it­ed process­es.” This is why Cam­bridge Uni­ver­si­ty refused to archive Newton’s alchem­i­cal papers in 1888, and why his 1855 biog­ra­ph­er won­dered how he could be tak­en in by “the obvi­ous pro­duc­tion of a fool and a knave.” New­ton’s alche­my doc­u­ments passed qui­et­ly through many pri­vate col­lec­tors’ hands until 1936, when “the world of Isaac New­ton schol­ar­ship received a rude shock,” writes Indi­ana University’s online project, The Chym­istry of Isaac New­ton:

In that year the ven­er­a­ble auc­tion house of Sotheby’s released a cat­a­logue describ­ing three hun­dred twen­ty-nine lots of Newton’s man­u­scripts, most­ly in his own hand­writ­ing, of which over a third were filled with con­tent that was unde­ni­ably alchem­i­cal.

Marked “not to be print­ed” upon his death in 1727, the alchem­i­cal works “raised a host of inter­est­ing ques­tions in 1936 as they do even today.” Those ques­tions include whether or not New­ton prac­ticed alche­my as an ear­ly sci­en­tif­ic pur­suit or whether he believed in a “secret the­o­log­i­cal mean­ing in alchem­i­cal texts, which often describe the trans­mu­ta­tion­al secret as a spe­cial gift revealed by God to his cho­sen sons.” The impor­tant dis­tinc­tion comes into play in Ted Chiang’s dis­cus­sion of Clarke’s Third Law:

Sup­pose some­one says she can trans­form lead into gold. If we can use her tech­nique to build fac­to­ries that turn lead into gold by the ton, then she’s made an incred­i­ble sci­en­tif­ic dis­cov­ery. If on the oth­er hand it’s some­thing that only she can do… then she’s a magi­cian.

Did New­ton think of him­self as a magi­cian? Or, more prop­er­ly giv­en his reli­gios­i­ty, as God’s cho­sen ves­sel for alchem­i­cal trans­for­ma­tion? It’s not entire­ly clear what he believed about alche­my. But he did take the prac­tice of what was then called “chym­istry” as seri­ous­ly as he did his math­e­mat­ics. James Voelkel, cura­tor of the Chem­i­cal Her­itage Foun­da­tion—who recent­ly pur­chased the Philoso­phers’ stone recipe—tells Live­science that its author, Starkey, was “prob­a­bly American’s first renowned, pub­lished sci­en­tist,” as well as an alchemist. While New­ton may not have tried to make the mer­cury, he did cor­rect Starkey’s text and write his own exper­i­ments for dis­till­ing lead ore on the back.

Indi­ana Uni­ver­si­ty sci­ence his­to­ri­an William New­man “and oth­er his­to­ri­ans,” notes Nation­al Geo­graph­ic, “now view alchemists as thought­ful tech­ni­cians who labored over their equip­ment and took copi­ous notes, often encod­ing their recipes with mytho­log­i­cal sym­bols to pro­tect their hard-won knowl­edge.” The occult weird­ness of alche­my, and the strange pseu­do­nyms its prac­ti­tion­ers adopt­ed, often con­sti­tut­ed a means to “hide their meth­ods from the unlearned and ‘unwor­thy,’” writes Dan­ny Lewis at Smith­son­ian. Like his fel­low alchemists, New­ton “dili­gent­ly doc­u­ment­ed his lab tech­niques” and kept a care­ful record of his read­ing.

“Alchemists were the first to real­ize that com­pounds could be bro­ken down into their con­stituent parts and then recom­bined,” says New­man, a prin­ci­ple that influ­enced Newton’s work on optics. It is now acknowl­edged that—while still con­sid­ered a mys­ti­cal pseudoscience—alchemy is an impor­tant “pre­cur­sor to mod­ern chem­istry” and, indeed, as Indi­ana Uni­ver­si­ty notes, it con­tributed sig­nif­i­cant­ly to ear­ly mod­ern phar­ma­col­o­gy” and “iatro­chem­istry… one of the impor­tant new fields of ear­ly mod­ern sci­ence.” The suf­fi­cient­ly advanced tech­nol­o­gy of chem­istry has its ori­gins in the mag­ic of “chym­istry,” and New­ton was “involved in all three of chymistry’s major branch­es in vary­ing degrees.”

Newton’s alchem­i­cal man­u­script papers, such as “Artephius his secret Book” and “Her­mes” sound noth­ing like what we would expect of the dis­cov­er­er of a “clock­work uni­verse.” You can read tran­scrip­tions of these man­u­scripts and sev­er­al dozen more at The Chym­istry of Isaac New­ton, where you’ll also find an Alchem­i­cal Glos­sary, Sym­bol Guide, sev­er­al edu­ca­tion­al resources, and more. The man­u­scripts not only show Newton’s alche­my pur­suits, but also his cor­re­spon­dence with oth­er ear­ly mod­ern alchem­i­cal sci­en­tists like Robert Boyle and Starkey, whose recipe—titled “Prepa­ra­tion of the [Socph­ick] Mer­cury for the [Philoso­phers’] stone by the Antin­o­mi­al Stel­late Reg­u­lus of Mars and Luna from the Man­u­scripts of the Amer­i­can Philosopher”—will be added to the Indi­ana Uni­ver­si­ty online archive soon.

Relat­ed Con­tent:

In 1704, Isaac New­ton Pre­dicts the World Will End in 2060

Sir Isaac Newton’s Papers & Anno­tat­ed Prin­cip­ia Go Dig­i­tal

Isaac New­ton Cre­ates a List of His 57 Sins (Cir­ca 1662)

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness