Omnia apud me mathematica fiunt.

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.

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

On the one hand I have a clear and distinct idea of myself, in so far as I am a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far a this is simply an extended, non-thinking thing. And, accordingly, it is certain that I am really distinct from my body, and exist without it.

Just as we believe by faith that the greatest happiness of the next life consists simply in the contemplation of this divine majesty, likewise we experience that we derive the greatest joy of which we are capable in this life from the same contemplation, even though it is much less perfect.

So far, I have been a spectator in this theater which is the world, but I am now about to mount the stage, and I come forward masked.

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.