Quote by René Descartes: “I think, therefore I am.”

The one thing you cannot doubt is that you are currently doubting — and doubting requires a mind to do it. This is Descartes's attempt to find bedrock certainty in a world where everything else seemed questionable. The act of thinking proves the thinker exists.

Descartes published the Discourse on the Method in 1637, during the Thirty Years' War, a period of catastrophic religious and political violence across Europe. His project of methodical doubt was partly a search for truths that could survive the collapse of all inherited certainties.

French philosopher and mathematician whose Discourse on the Method and Meditations on First Philosophy founded modern rationalist philosophy. He is credited with establishing the mind-body problem and introducing the coordinate system that bears his name.