Science has been seriously retarded by the study of what is not worth knowing and of what is not knowable.

The artist may be well advised to keep his work to himself till it is completed, because no one can readily help him or advise him with it... but the scientist is wiser not to withhold a single finding or a single conjecture from publicity.

To make a young couple love each other, it is only necessary to oppose and separate them.

What must the English and French think of the language of our philosophers when we Germans do not understand it ourselves?

God made man simple, but how he changed and got complicated is hard to say.

In nature we never see anything isolated, but everything in connection with something else which is before it, beside it, under it and over it.

He who is plenteously provided for from within needs but little from without.