Rationalism is an attitude of readiness to listen to contrary arguments and to learn from experience... of admitting that "I may be wrong and you may be right and, by an effort, we may get nearer the truth."

Every solution of a problem raises new unsolved problems.

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.

If you know that things are bound to happen whatever you do, then you may feel free to give up the fight against them.

It must be possible for an empirical system to be refuted by experience.

No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.

It is impossible to speak in such a way that you cannot be misunderstood.