Knowledge is realizing that the street is one way; wisdom is looking in both directions anyway.

Love is not the stupidest thing a man does, but it cannot be blamed on gravity.

External conditions can, to a certain extent, reduce, but never cancel individual repsonsibility.

As long as I have any choice in the matter, I shall live only in a country where civil liberty, tolerance and equality of all citizens before the law prevail.

To act intelligently in human affairs is only possible if an attempt is made to understand the thoughts, motives, and apprehension of one's opponent so fully that one can see the world through their eyes.

The only rational way of educating is to be an example. If one can't help it, a warning example.

The supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a simple datum of experience.