“The quest for precision is analogous to the quest for certainty, and both should be abandoned.”

I would rather find a single causal law than be the king of Persia!

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

All life is problem-solving.

In my view, aiming at simplicity and lucidity is a moral duty of all intellectuals: lack of clarity is a sin, and pretentiousness is a crime.

He who decides one day that scientific statements do not call for any further test and that they can be regarded as finally verified retires from the game.

The way of science is paved with discarded theories that were once declared self-evident.

The method of learning by trial and error – of learning from our mistakes – seems to be fundamentally the same whether it is practiced by lower or by higher animals, by chimpanzees, or by men of science.

In philosophy methods are unimportant; any method is legitimate if it leads to results capable of being rationally discussed.

In so far as a scientific statement speaks about reality, it must be falsifiable: and in so far as it is not falsifiable, it does not speak about reality.

Theology, I still think, is due to a lack of faith.

Science may be described as the art of systematic oversimplification.

The game of science is, in principle, without end.

The essential feature of dualist-interactionism is that the mind and brain are independent entities and that they interact by quantum physics.

“It can’t happen here” is always wrong: a dictatorship can happen anywhere.

A theory that explains everything, explains nothing.

If our civilization is to survive, we must break with the habit of deference to great men.