Intuition is the undoubting conception of a pure and attentive mind, which arises from the light of reason alone, and is more certain than deduction.

In God there is an infinitude of things which I cannot comprehend, nor possibly even reach in any way by thought; for it is the nature of the infinite that my nature, which is finite and limited, should not comprehend it.

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

In the matter of a difficult question it is more likely that the truth should have been discovered by the few than by the many.

How can you be certain that your whole life is not a dream?

Give me extension and motion and I will construct the universe.

The mind effortlessly and automatically takes in new ideas, which remain in limbo until verified or rejected by conscious, rational analysis.