Whom conscience, ne'er asleep, Wounds with incessant strokes, not loud, but deep.

From Obedience and submission comes all our virtues, and all sin is comes from self-opinion.

Wonder is the foundation of all philosophy, inquiry the progress, ignorance the end.

In my youth I studied for ostentation; later, a little to gain wisdom; now, for recreation; never for gain.

Whenever a new finding is reported to the world people say - It is probably not true. Later on, when the reliability of a new finding has been fully confirmed, people say - OK, it may be true but it has no real significance. At last, when even the significance of the finding is obvious to everybody, people say - Well, it might have some significance, but the idea is not new.

My trade and my art is living. He who forbids me to speak about it according to my sense, experience, and practice, let him orderthe architect to speak of buildings not according to himself but according to his neighbor; according to another man's knowledge, not according to his own.

I speak the truth, not my fill of it, but as much as I dare speak; and I dare to do so a little more as I grow old.