You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "what philosopher said i think therefore i am?" whose answer is René Descartes.
Each document should contain about 30 words, and these documents should contain useful information.

Query: who said "I think, therefore I am"
Useful Output:

Doc 1: Descartes' quote, "I think, therefore I am," remains popular even today. The concept is used in many variations of the joke: Rene Descartes
Doc 2: Rene Descartes, French philosopher and mathematician wrote 'I think, therefore I am'. Except that he rendered it in Latin: 'Cogito ergo sum'
Doc 3: "I think, therefore I am" is a philosophical Latin statement proposed by René Descartes. Taken from here.
Doc 4: I Think Therefore I Am Descartes Cogito Ergo Sum Explained 17th century philosopher. Descartes exultant declaration I think therefore I am is his defining
Doc 5: The philosopher Rene Descartes is responsible for the popular saying “I think, therefore I am”. But what is the significance of this quote?