I THINK THEREFORE I AM (Cogito ergo sum)

I THINK THEREFORE I AM - Rene Descartes 

“I think, therefore I am” is a philosophical Latin statement used by famous French philosophers, René Descartes. He realized that he could doubt everything he believed. The only thing left was this statement "cogito rego sum". Why this phrase was so famous? What made Descarte famous? 

Many have criticized Descartes. Some pointed out that if you are thinking, there has to be something (reality) that you must be thinking about; so thinking could not be the only thing you know for certain. Others deny that knowledge needs any foundation at all. The issue is very widely discussed and debated in epistemology, the theory of knowledge.

I interpret it as that nothing outside of your own mind exists, or can really be proven to exist. Personally, I cannot see how I can doubt the cogito. I do understand that thinking is not necessarily everything that constitutes my existence though.

I think of it nearly grammatical terms. I think therefore I am. That I think (and do other things like feel emotion and daydream) is beyond question therefore there must be an "I" to do these things. If it could be shown with completely certainty that any noun-verb statement was true, then we could know that the noun existed. A boy farted therefore there is a boy.