Prediction is very difficult, especially if it's about the future.

Everything we call real is made of things that cannot be regarded as real.

The best weapon of a dictatorship is secrecy, but the best weapon of a democracy should be the weapon of openness.

Every valuable human being must be a radical and a rebel, for what he must aim at is to make things better than they are.

The opposite of a fact is falsehood, but the opposite of one profound truth may very well be another profound truth.

Every great and deep difficulty bears in itself its own solution. It forces us to change our thinking in order to find it.

When searching for harmony in life one must never forget that in the drama of existence we are ourselves both actors and spectators.