Seems to be a deep instinct in human beings for making everything compulsory that isn't forbidden.
To stay young requires unceasing cultivation of the ability to unlearn old falsehoods.
If you've got the truth you can demonstrate it. Talking doesn't prove it.
Behind every mystery lies another mystery.
Never attempt to teach a pig to sing; it wastes your time and annoys the pig.
Each man is his own prisoner, in solitary confinement for life.