Did Descartes Sleep in an Oven?
There is somewhat famous story involving René Descartes sleeping in an oven and then awaking with great insights into philosophy and mathematics. The story is romanticized, but it does have aspects of truth to it. The true story can be summed up as:
While we can confirm Descartes invented analytical geometry, and that he likely slept in a room with a masonry heater on a cold November in 1619, the rest of the story is bound to remain legend. We explain below.
This short video discusses René Descartes.
What Does it Mean to Sleep in a Room with an Oven?
We cannot say for sure what manner of bed Descartes used, but throughout human history, people have struggled to remain warm during cold weather. 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.
All About Masonry Heaters.
The Real Story of René Descartes’s Visions and “The Oven”
According to Adrien Baillet, 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.
While we can’t prove that this was the moment Descartes had these inspirations, we can prove that:
- The over heated room was likely heated by a masonry heater.
- Descartes came up with these ideas in or around this time.
TIP: Another version of the story has a fly crawling a the clinging of his room. 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. 
FACT: Descartes’ Geometry was originally an appendix to a larger work called Discourse on the Method of Properly Conducting One’s Reason and of Seeking the Truth in the Sciences
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.
I strongly suggest reading the Major works of Descartes including:
- Discourse on the Method – where he first describes analytical geometry. That part is 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).