With the growth of knowledge our ideas must from time to time be organized afresh. The change takes place usually in accordance with new maxims as they arise, but it always remains provisional.

If I work incessantly to the last, nature owes me another form of existence when the present one collapses.

Not art and science only, but patience will be required for the work.

And I like those authors best whose scenes describe my own situation in life-- and the friends who are about me whose stories touch me with interest, from resembling my own homely existence.

The world only goes forward because of those who oppose it.

God could cause us considerable embarrassment by revealing all the secrets of nature to us: we should not know what to do for sheer apathy and boredom.

Just trust yourself and you'll learn the art of living.