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.

In the middle of difficulty lies opportunity.

It is not the fruits of scientific research that elevate man and enrich his nature. but the urge to understand, the intellectual work, creative or receptive.

A man's ethical behavior should be based effectually on sympathy, education, and social ties; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death.

There is only the way of intuition, which is helped by a feeling for the order lying behind the appearance.

It is a miracle that curiosity survives formal education.

Setting an example is not the main means of influencing another, it is the only means.

It you want to live a happy life, tie it to a goal – not to people or things.

The further the spiritual evolution of mankind advances, the more certain it seems to me that the path to genuine religiosity does not lie through the fear of life, and the fear of death, and blind faith, but through striving after rational knowledge.

Great spirits have always found violent opposition from mediocre minds. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence and fulfills the duty to express the results of his thoughts in clear form.