Who is known for this theory "Corgito ergo sum"?

Question: Who is known for this theory "Corgito ergo sum"!?
Best Answer - Chosen by Asker:

"Cogito ergo sum" (I think, therefor I am) is from the philosopher Rene' Descartes!. It means that the act of consciousness is evidence that one does in fact exist - that one cannot be conscious without having existence!.Www@QuestionHome@Com

Renee DesCartes, from the Meditations, Chapter 2!.
Dubeo ergo cogito ergo sum!.
I doubt therefore I think therefore I am!.
The first part is often left off!.
Doubt is a form of thought!. You cannot conceivably doubt that you doubt!. Doubt is a form of thought!. If there is thought, there must be a thinker!. Hence you can prove your own existence!.

DesCartes went on to claim a proof of God and the external world, but most generally consider that everything after chapter 2 was completely wrong and he only managed to show that each of us can prove to ourselves that we exist!.Www@QuestionHome@Com