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 of many things of very great importance. Theology, on the other hand induces a dogmatic belief that we have knowledge where in fact we have ignorance and by doing so generates a kind of impertinent insolence towards the universe. Uncertainty in the presence of vivid hopes and fears is painful, but must be endured if we wish to live without the support of comforting fairy tales.

Unfortunately, however, power is sweet, and the man who in the beginning seeks power merely in order to have scope for his benevolence is likely, before long, to love the power for its own sake.

Science may set limits to knowledge, but should not set limits to imagination.

There will still be things that machines cannot do. They will not produce great art or great literature or great philosophy; they will not be able to discover the secret springs of happiness in the human heart; they will know nothing of love and friendship.

When one admits that nothing is certain one must, I think, also admit that some things are much more nearly certain than others.

Emphatic and reiterated assertion, especially during childhood, produces in most people a belief so firm as to have a hold even over the unconscious.

Science, by itself, cannot supply us with an ethic. It can show us how to achieve a given end, and it may show us that some ends cannot be achieved. But among ends that can be achieved our choice must be decided by other than purely scientific considerations. If a man were to say, "I hate the human race, and I think it would be a good thing if it were exterminated," we could say, "Well, my dear sir, let us begin the process with you." But this is hardly argument, and no amount of science could prove such a man mistaken.