We know very little, and yet it is astonishing that we know so much, and still more astonishing that so little knowledge can give us so much power.

The affection of parents makes infants feel safe in this dangerous world, and gives them boldness in experimentation and in exploration of their environments.

Love must feel the ego of the beloved person as important as one's own ego, and must realize the other's feelings and wishes as though they were one's own.

Nothing can penetrate the loneliness of the human heart except the highest intensity of the sort of love the religious teachers have preached.

In Labor movements generally, success through violence can hardly be expected except in circumstances where success without violence is attainable.

We have in fact, two kinds of morality, side by side: one which we preach, but do not practice, and another which we practice, but seldom preach.

Science tells us what we can know, but what we can know is little, and if we forget how much we cannot know, we become insensitive to many things of great importance.

The more we realize our minuteness and our impotence in the face of cosmic forces the more astonishing becomes what human beings have achieved.