Who said "The only thing we can know for certain is that we think."?

This quote is attributed to Descartes, René.

The only thing we can know for certain is that we think. - Descartes, René

"The only thing we can know for certain is that we think."

Descartes, René Knowledge

Philosopher-Mathematician French 1596–1650

"I think, therefore I am."

"The greatest minds are capable of the greatest vices as well as of the greatest virtues."

"Doubt is the key to knowledge."

"If you would be a real seeker of truth, it is necessary that at least once in your life you doubt, as far as possible, all things."

"We're not just after treasure. We're preserving history."

"The mind is humanity's greatest tool."

"A tidy room reflects a tidy mind."

"You can learn a lot about a person by how they keep their space."