"The light of natural reason is sufficient to give us a clear and distinct conception of God."

"I perceived it was possible to arrive at knowledge highly useful in life; and that, instead of the speculative philosophy usually taught in the Schools, we might find a practical, by means of which, k…"

"The first precept was never to accept anything for true which I did not clearly know to be such."

"The mind is more easily known than the body."

"The mind is a substance whose whole essence or nature consists only of thinking."