Those who have no hope for a future life are already dead for the present one.

All theory, my friend, is grey, But green is life's glad golden tree.

Master and Doctor are my titles; for ten years now, without repose, I held my erudite recitals and led my pupils by the nose.

What one doesn't understand one doesn't possess.

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

The intelligent man finds almost everything ridiculous, the sensible man hardly anything.

Nature does not suffer her veil to be taken from her, and what she does not choose to reveal to the spirit, thou wilt not wrest from her by levers and screws.