1. Although Descartes is primarily known for his philosophy, he was also a mathematician. He created the rectangular coordinate system, which is also known as the Cartesian coordinate system. It is rumored that he came up with the system while lying in bed, watching a bug crawl on his ceiling. He also believed that monkeys were able to talk, but did not communicate with humans so as not to be controlled by them.
2. Descartes entered the Jesuit college of La Flèche in Anjou at the age of eight and studied there for eight years.
3. Because of his poor health, Descartes was allowed to sleep in an extra five hours at his school. In fact, it is rumored that he never awoke before 11 in the morning! Despite the lost time, Descartes was still considered an excellent student, preferring to do his work in bed.
3. Descartes stood only 5’1″ tall.
4. Descartes had a daughter, Francine, with a domestic servant named Helena Jans van der Strom. Although Francine was considered an illegitimate child of Descartes, her baptism records record her birth as legitimate. She died at the young age of five of scarlet fever.
5. Descartes loved to dress up in fancy clothes. He was rarely caught in any casual clothing!
6. Although it never interested him, Descartes was a licensed lawyer. However, he never entered the practice, preferring philosophy instead.
7. In 1619, Descartes believed he received some prophetic dreams. These dreams encouraged him to pursue knowledge, truth, and philosophy. He claimed that by following these visions, he was able to come up with analytical geometry.
8. Startled by Galileo’s house arrest for his heretical publications, Descartes became more private with his own writings, and parts of his works, especially Le Monde, were destroyed.
9. Descartes corresponded with Princess Elizabeth of Bohemia and exchanged philosophical ideas with her. His Principia Philosophiae was dedicated to her.
10. Descartes died in Stockholm, Sweden in 1650. But because Descartes was a devout Catholic, he was initially buried in a cemetery for unbaptized babies as Sweden was a Protestant country. His remains are now rumored to be in the Panthéon, and there is a possibility that his heart is in a cemetery in Paris.