What is part of you, you cannot get rid of, even if you were to throw it away.

Experiments are mediators between nature and idea.

Sameness leaves us in peace but it is contradiction that makes us productive.

How many years must a man do nothing, before he can at all know what is to be done and how to do it!

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.

It is so hard that one cannot really have confidence in doctors and yet cannot do without them.

When we see the many grave-stones which have fallen in, which have been defaced by the footsteps of the congregation, which lie buried under the ruins of the churches, that have themselves crumbled together over them; we may fancy the life after death to be as a second life, into which man enters in the figure, or the picture or the inscription, and lives longer there than when he was really alive. But this figure also, this second existence, dies out too, sooner or later. Time will not allow himself to be cheated of his rights with the monuments of men or with themselves.