A man of spirit must not think of the word difficulty as so much as existing. Away with it!

Nothing can contribute more to peace of soul than the lack of any opinion whatever.

The more experiences and experiments accumulate in the exploration of nature, the more precarious the theories become. But it is not always good to discard them immediately on this account. For every hypothesis which once was sound was useful for thinking of previous phenomena in the proper interrelations and for keeping them in context. We ought to set down contradictory experiences separately, until enough have accumulated to make building a new structure worthwhile.

After all, is our idea of God anything more than personified incomprehensibility?

A schoolteacher or professor cannot educate individuals, he educates only species.

If nature be regarded as the teacher and we poor human beings as her pupils, the human race presents a very curious picture. We all sit together at a lecture and possess the necessary principles for understanding it, yet we always pay more attention to the chatter of our fellow students than to the lecturer's discourse. Or, if our neighbor copies something down, we sneak it from him, stealing what he himself may have heard imperfectly, and add it to our own errors of spelling and opinion.

Nowadays beautiful women are counted among the talents of their husbands.