What you wish to do you are apt to think you ought to do.

When curiosity turns to serious matters, it's called research.

Many a truth is the result of an error.

If there be a faith that can move mountains, it is faith in one's own power.

The simplest and most familiar truth seems new and wonderful the instant we ourselves experience it for the first time.

Distrust your judgment the moment you can discern the shadow of a personal motive in it.

You stay young as long as you can learn, acquire new habits, and suffer contradictions.