If a theory can not be explained to a child, then the theory is probably worthless.

Weakness of attitude becomes weakness of character.

Intelligence makes clear to us the interrelationship of means and ends. But mere thinking cannot give us a sense of the ultimate and fundamental ends. To make clear these fundamental ends and valuations and to set them fast in the emotional life of the individual, seems to me precisely the most important function which religion has to form in the social life of man.

Lasting harmony with a woman (was) an undertaking in which I twice failed rather disgracefully.

As the area of light expands, so does the perimeter of darkness.

The creative principle [of science] resides in mathematics.

Out of the multitude of our sense experiences we take, mentally and arbitrarily, certain repeatedly occurring complexes of sense impression (partly in conjunction with sense impressions which are interpreted as signs for sense experiences of others), and we attribute to them a meaning the meaning of the bodily object.