All religions, arts and sciences are branches of the same tree. All these aspirations are directed toward ennobling man's life, lifting it from the sphere of mere physical existence and leading the individual towards freedom.

Every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving.

Imagination without knowledge may create beautiful things, knowledge without imagination can create only perfect ones.

Don't wait for miracles, your whole life is a miracle.

I want to go when I want. It is tasteless to prolong life artificially. I have done my share, it is time to go. I will do it elegantly.

We must not conceal from ourselves that no improvement in the present depressing situation is possible without a severe struggle; for the handful of those who are really determined to do something is minute in comparison with the mass of the lukewarm and the misguided. And those who have an interest in keeping the machinery of war going are a very powerful body; they will stop at nothing to make public opinion subservient to their murderous ends.

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.