- But then I noticed that while I was thinking that everything was false, it was absolutely necessary that I, who was thinking this, must exist. I realized that the statement I think, therefore I am was so certain and clear that no doubt, no matter how extreme, could undermine it. I concluded that I could accept this as the first principle of the philosophy I was seeking.
- But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat; and as I observed that this truth, I think, hence I am, was so certain and of such evidence, that no ground of doubt, however extravagant, could be alleged by the Sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the Philosophy of which I was in search.