The difference between stupidity and genius is that genius has its limits.

Science without religion is lame, religion without science is blind.

Common sense consists of those layers of prejudice laid down before the age of 18.

The individual must not merely wait and criticize, he must defend the cause the best he can. The fate of the world will be such as the world deserves.

When we are working at something, we come down from our high logical horse and sniff around with our nose to the ground. Then we obliterate our traces in order to become more God-like.

All our thoughts and concepts are called up by sense-experiences and have a meaning only in reference to these sense-experiences. On the other hand, however, they are products of the spontaneous activity of our minds; they are thus in no wise logical consequences of the contents of these sense-experiences. If, therefore, we wish to grasp the essence of a complex of abstract notions we must for the one part investigate the mutual relationships between the concepts and the assertions made about them; for the other, we must investigate how they are related to the experiences.

I have never belonged wholeheartedly to country or State, to my circle of friends or even to my own family... Such isolation is sometimes bitter, but I do not regret being cut off from the understanding and sympathy of other men. I lose something by it,to be sure, but I am compensated for it in being rendered independent of the customs, opinions and prejudices of others, and am not tempted to rest my peace of mind upon such shifting foundations.