“Great men may make great mistakes.”

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.

The simple truth is that truth is hard to come by, and that once found may easily be lost again.

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

Every intellectual has a very special responsibility. He has the privilege and the opportunity of studying.

The aim of argument, or of discussion, should not be victory but progress.