Some years ago I was struck by the large number of falsehoods that I had accepted as true in my childhood, and by the highly doubtful nature of the whole edifice that I had subsequently based on them. I realized that it was necessary, once in the course of my life, to demolish everything completely and start again right from the foundations if I wanted to establish anything at all in the sciences that was stable and likely to last.

Conquer yourself rather than the world.

With me, everything turns into mathematics.

I am indeed amazed when I consider how weak my mind is and how prone to error.

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.

The greatest minds are capable of the greatest vices as well as of the greatest virtues.

I experienced in myself a certain capacity for judging which I have doubtless received from God, like all the other things that I possess; and as He could not desire to deceive me, it is clear that He has not given me a faculty that will lead me to err if I use it aright.