That which is impenetrable to us really exists. Behind the secrets of nature remains something subtle, intangible, and inexplicable. Veneration for this force beyond anything that we can comprehend is my religion.

The goal of pacifism is possible only though a supranational organization. To stand unconditionally for this cause is the criterion of true pacifism.

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.

Smoke like a chimney, work like a horse, eat without thinking, go for a walk only in really pleasant company.

But there is another reason for the high repute of mathematics: it is mathematics that offers the exact natural sciences a certain measure of security which, without mathematics, they could not attain.

I cannot conceive of a personal God who would directly influence the actions of individuals, or would directly sit in judgment on creatures of his own creation. I cannot do this in spite of the fact that mechanistic causality has, to a certain extent, been placed in doubt by modern science. My religiosity consists in a humble admiration of the infinitely superior spirit that reveals itself in the little that we, with our weak and transitory understanding, can comprehend of reality. Morality is of the highest importance - but for us, not for God.

No worthy problem is ever solved within the plane of its original conception.