René Descartes

or Cartesius ( – )

• "Je pense, donc je suis."
  • Translation: "I think, therefore I am."
  • Source: Discours de la méthode

• "Cogito, ergo sum."
  • Translation: "I think, therefore I am."
  • Source: Principia philosophiae

• "Ex nihilo nihil fit."
  • Translation: "Nothing comes out of nothing."
  • Source: Principia philosophiae

• "Dubium sapientiae initium."
  • Translation: "Doubt is the origin of wisdom."
  • Source: Meditationes de prima philosophiae