Secret thoughts are only half free: they fly undisturbed in the skies of the inner freedom, but they can never leave them.

When you would suffocate or ignore dissent, remember how many times you dissented.

As long as his strength permits, the poor mortal must always climb new mountains.

Do not confuse fantasy with imagination; the former consumes itself in daydreaming, the latter stimulates creativity in the arts and in the sciences.

Sometimes true tolerance requires an extraordinary strength, which we are often too weak to exercise.

Inner freedom demands the rejection of any imposition that injures our dignity.

We learn a lot from the mistakes of others, but even more from our own.