Medicine to produce health must examine disease and music, to create harmony must investigate discord.

What we achieve inwardly will change outer reality.

The mind is not a vessel to be filled but a fire to be kindled.

I would rather excel in the knowledge of what is excellent, than in the extent of my power and possessions.

To make no mistakes is not in the power of man but from their errors and mistakes the wise and good learn wisdom for the future.