Rene Descartes
- Meditations on First Philosophy
Does it now follow that I too do not exist? No: if I convinced myself of something then I certainly existed... let him deceive me as much as he can, he will never bring it about that I am nothing so long as I think that I am something. So after considering everything very thoroughly, I must finally conclude that this proposition - "I am, I exist" - is necessarily true whenever it is put forward by me or conceived in my mind.
