When I turn my mind's eye upon myself, I understand that I am a thing which is incomplete and dependent on another and which aspires without limit to… - René Descartes

Therefore from the fact alone that I know that I exist and that, at the same time, I notice absolutely nothing else that belongs to my nature apart from the single fact that I am a thinking thing, I correctly conclude that my essence consists in this alone, that I am a thinking thing.

Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has.

I am like a prisoner who happens on enjoy an imaginary freedom in his dreams and who subsequently begins to suspect that he is asleep and, afraid of being awakened, conspires silently with his agreeable illusions.