I think, therefore I am.
Cogito, ergo sum.

Philosophers
René Descartes
French philosopher-mathematician born in 1596 who launched modern thought with "I think, therefore I am." His methodical doubt rebuilt knowledge on certainty, while his coordinate system fused geometry and algebra.
View this figure's profile
René Descartes's Other Quotes
Related Quotes
Fables should be taught as fables, myths as myths, and miracles as poetic fancies.
-- Hypatia
For Being is, and non-Being is not.
-- Parmenides
For thinking and Being are the same.
-- Parmenides
Philosophy is the knowledge of beings qua beings.
-- Farabi
For whom emptiness works, everything works. For whom emptiness does not work, nothing works.
-- Nagarjuna
The course of Heaven is constant: it does not prevail because of Yao, nor does it cease because of Jie.
-- Xunzi