I am thinking, therefore I exist. (...) I was a substance whose whole essence or nature is solely to think, and which does not require any place, or depend on any material thing, in order to exist. Accordingly this 'I' - that is, the soul by which I am what I am - is entirely distinct from the body, and indeed is easier to know than the body, and would not fail to be whatever it is, even if the body did not exist.

It's the familiar love-hate syndrome of seduction: "I don't really care what it is I say, I care only that you like it."

Few look for truth; many prowl about for a reputation of profundity by arrogantly challenging whichever arguments are the best.

The entire method consists in the order and arrangement of the things to which the mind's eye must turn so that we can discover some truth.

Omnia apud me mathematica fiunt.

Whatever I have up till now accepted as most true and assured I have gotten either from the senses or through the senses. But from time to time I have found that the senses deceive, and it is prudent never to trust completely those who have deceived us even once.

Even if I were to suppose that I was dreaming and whatever I saw or imagined was false, yet I could not deny that ideas were truly in my mind.