it's only an one answer to this question. quite convincing anyway, but not completely. I try to think in different way, that why I'm asking this question. I don't know if it does or if it doesn't mather, but the whole sentence of Descartes is "I DOUBT, therefore I think, therefore I am".
and I don't know if this what I call life is really a life, do I? so I can't claim that I'm here, who can prove it?
just live ur life...without thinking? without doubting? I don't doubt therefore I don't think therefore I am not.