Descartes

Descartes is invoked in The Notetaking Cold War as an example of an “essentialist” philosopher — grouped with Plato and Immanuel Kant as thinkers who hold that things have an underlying essence, even though their philosophical stances differ widely.

Context: René Descartes (1596–1650) was a French philosopher and mathematician, the father of modern rationalist philosophy, known for “Cogito, ergo sum” (“I think, therefore I am”).