For to be possessed of a vigorous mind is not enough; the prime requisite is rightly to apply it.

I desire to live in peace and to continue the life I have begun under the motto 'to live well you must live unseen

I hope that posterity will judge me kindly, not only as to the things which I have explained, but also to those which I have intentionally omitted so as to leave to others the pleasure of discovery.

Divide each difficulty into as many parts as is feasible and necessary to resolve it.

I am thing that thinks: that is, a things that doubts,affirms, denies, understands a few things, is ignorant of many things, is willing, is unwilling, and also which imagines and has sensory perceptions.

The first precept was never to accept a thing as true until I knew it as such without a single doubt.

Now therefore, that my mind is free from all cares, and that I have obtained for myself assured leisure in peaceful solitude, I shall apply myself seriously and freely to the general destruction of all my former opinions.