René Descartes (1596-1650) was a French mathematician, natural scientist, and philosopher, best known by the phrase 'Cogito ergo sum' ('I think therefore I am'). He published works on optics, coordinate geometry, physiology, and cosmology, however, he is mostly remembered as the "father of modern philosophy". He lived in a time preceding the Age of Enlightenment that flourished in Europe in the late 17th and throughout the 18th century, a period of revolutionary ideas in government, individual freedom, and religious beliefs. While not a direct participant in the Enlightenment, Descartes' legacy would be his influence on those who contributed to the scientific, political, and social changes throughout this age, an age of reason.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Rene_Descartes/.