Thus science must begin with myths, and with the criticism of myths; neither with the collection of observations, nor with the invention of experiments, but with the critical discussion of myths, and of magical techniques and practices.

A system is empirical or scientific only if it is capable of being tested by experience. These considerations suggest that not the verifiability but the falsifiability of a system is to be taken as a criterion of demarcation... It must be possible for an empirical or scientific system to be refuted by experience.

We must plan for freedom, and not only for security, if for no other reason than only freedom can make security more secure.

A theory that explains everything, explains nothing

The growth of knowledge depends entirely upon disagreement.

We should realize that, if [Socrates] demanded that the wisest men should rule, he clearly stressed that he did not mean the learned men; in fact, he was skeptical of all professional learnedness, whether it was that of the philosophers or of the learned men of his own generation, the Sophists. The wisdom he meant was of a different kind. It was simply the realization: how little do I know! Those who did not know this, he taught, knew nothing at all. This is the true scientific spirit.

The use of violence is justified only under a tyranny which makes reforms without violence impossible, and should have only one aim, that is, to bring about a state of affairs which makes reforms without violence possible.