The phrase “I think, therefore I am” was said by the French philosopher René Descartes.

Who said it?

  • The quote comes from René Descartes (1596–1650) , a French philosopher and mathematician often called the “father of modern philosophy”.
  • In Latin he wrote it as “Cogito, ergo sum” , and in French as “Je pense, donc je suis.”

Where does it appear?

  • The famous wording first appears in his 1637 work “Discourse on the Method” , where he introduces it as a foundation for certain knowledge.
  • He restates the same idea in “Meditations on First Philosophy” (1641) as “I am, I exist” while exploring what can be known for sure.

What does it mean, briefly?

  • Descartes argues that even if everything else is doubted, the very act of thinking or doubting proves there is a thinker, so his own existence is indubitable.
  • So the line is meant as a proof that conscious thinking guarantees the existence of the self at least in the moment of thinking.

TL;DR: “I think therefore I am who said it?” → It was said by René Descartes , a 17th‑century French philosopher, in his works Discourse on the Method and Meditations on First Philosophy.

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