Some creatures are made to see in the dark.

Yet we must try the harder, the less the prospect of success.

You can hardly convince a man of an error in a lifetime, but must content yourself with the reflection that the progress of science is slow. If he is not convinced, his grandchildren may be.

To him whose elastic and vigorous thought keeps pace with the sun, the day is a perpetual morning.

Philosophy, having crept clinging to the rocks so far, puts out its feelers many ways in vain.

If within the sophisticated man there is not an unsophisticated one, then he is but one of the devil's angels.

We find it difficult to choose our direction because it does not yet exist distinctly in our idea.