Did Descartes Sleep in an Oven?
There is somewhat famous story involving René Descartes sleeping in an oven (or stove) and then awaking with great insights into philosophy and mathematics. The story is likely somewhat romanticized (by Descartes himself and subsequently others), but it does have aspects of truth to it. The true story can be summed up as:
René Descartes didn’t sleep in a literal oven, but he did invent analytical geometry while sleeping in a room with an oven (likely a masonry heater). Or more specifically, he says he slept in a “poêle,” a French term that translates to “stove.”
Regardless of how we translate “poêle”, we can be assured he slept in an “oven” heated room, not a literal oven.
This is almost certainly what Descartes meant when he tells his reader in some translations of Part II of his French text Discourse on the Method of Properly Conducting One’s Reason and of Seeking the Truth in the Sciences (or just Discourse on the Method),
Google Translation (from the French) version: “I was then in Germany, where the occasion of the wars, which are not yet finished, had called me; And as I was returning from the coronation of the Emperor to the army, the commencement of the winter stopped me in a quarter, where, finding no conversation which amused me, and having, besides, fortunately, no care nor passions that disturbed me, I remained all day locked up alone in a stove, where I had every leisure to converse with my thoughts.”
A Common Translation: “… I remained each entire day, alone in a closed oven [poêle], where I had all the time, at my leisure, to entertain myself with my own thoughts.”
While we can confirm Descartes invented analytical geometry, and that he likely had his breakthrough as he slept in a room with a masonry heater on a cold November night or two in 1619 (like he eludes in his Discourse and like Adrien Baillet later confirms), the idea that he slept in a literal oven of the type we find in our kitchen is a misunderstanding of Descartes’s terminology.
We offer more details on this story below.
TIP: If you want the full story, see: Descartes’s Secret Notebook … Chapter 4, page 55 and 56.
This short video discusses René Descartes.
TIP: In most english translations of Descartes work the term “oven” is fully removed. Likely to avoid confusion. For example, one translation of Discourse says, “I was then in Germany, attracted thither by the wars in that country, which have not yet been brought to a termination; and as I was returning to the army from the coronation of the emperor, the setting in of winter arrested me in a locality where, as I found no society to interest me, and was besides fortunately undisturbed by any cares or passions, I remained the whole day in seclusion, with full opportunity to occupy my attention with my own thoughts.” In French, it is, “J’étois alors en Allemagne, où l’occasion des guerres qui n’y sont pas encore finies m’avoit appelé; et comme je retournois du couronnement de l’empereur vers l’armée, le commencement de l’hiver m’arrêta en un quartier où, ne trouvant aucune conversation qui me divertit, et n’ayant d’ailleurs, par bonheur, aucuns soins ni passions qui me troublassent, je demeurois tout le jour enfermé seul dans un poêle [AKA stove], où j’avois tout le loisir de m’entretenir de mes pensées.” See the French version of Discourse on Method where the term is used.
What Does it Mean to Sleep in a Room with an Oven?
Among other solutions to this problem was brick or masonry ovens or fireplaces, which sometimes included one or more platforms that would heat up as the fire burned. It could be covered with rugs or blankets and used as a sleeping area at night.
There is no way to tell exactly what sort of heated room Descartes enjoyed, but it certainly could have been of this type.
All About Masonry Heaters.
The Real Story of René Descartes’s Visions and “The Oven”
According to Adrien Baillet (a french scholar and Descartes biographer), on the night of 10–11 November 1619 (St. Martin’s Day), while stationed in Neuburg an der Donau, Descartes shut himself in a room with an “oven” (probably a Kachelofen or masonry heater) to escape the cold.
That night he was said to have had three visions and believed that a divine spirit revealed to him a new philosophy (analytical geometry). In his visions Descartes was said to have seen very clearly that all truths were linked with one another, so that finding a fundamental truth and proceeding with logic would open the way to all science.
Upon exiting the room he was said to have formulated analytical geometry and the idea of applying the mathematical method to philosophy. These inspirations led to his style of rational deductive reasoning, and the philosophies for which he is famous.
FACT: Descartes, born in 1596, and was a 23 year old serving as a mercenary in the Thirty Years’ War on the nights of 10-11 November 1619.
TIP: Another version of the story has a fly crawling a the clinging of his room. It is hard to say which details of the story are embellished and which are accurate details. Learn more from ualr.edu.
Did Descartes Really Invent Analytical Geometry?
While René Descartes isn’t the only person to “invent” analytical geography (Pierre de Fermat invented it simultaneously and independently) he is none-the-less known as it’s father. The Cartesian coordinate system used in analytical geometry (sometimes called Cartesian geometry) is a direct reference to Descartes. 
Analytical Geometry I.
What Else Did the Visions Inspire?
The inspiring visions Descartes had while sleeping on that cold night led to the inspiration for his most valued works including Discourse on the Method (1637) which contains the line “Cogito ergo sum” (I think, therefore I am) and his first description of analytical geometry.
Consider this passage from Part IV,
“… seeing that our senses sometimes deceive us, I was willing to suppose that there existed nothing really such as they presented to us; and because some men err in reasoning, and fall into paralogisms, even on the simplest matters of geometry, I, convinced that I was as open to error as any other, rejected as false all the reasonings I had hitherto taken for demonstrations; and finally, when I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams.
But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat; and as I observed that this truth, I think, therefore I am (COGITO ERGO SUM), was so certain and of such evidence that no ground of doubt, however extravagant, could be alleged by the sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search.”
I strongly suggest reading the Major works of Descartes including:
- Discourse on the Method – where he first describes analytical geometry (the one we discuss here) and details it in the section called La Géométrie.
- Meditations on First Philosophy – where he gives his take on metaphysics.
- Principles of Philosophy – where he sums up all previous philosophy and writes Newton’s first law of motion (before Newton), and further explains the mechanics behind “I think therefore I am”.
- Passions of the Soul – where he describes emotions (largely a work of social science).