Whenever a theory appears to you as the only possible one, take this as a sign that you have neither understood the theory nor the problem which it was intended to solve.
Karl Popper

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

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

Science must begin with myths, and with the criticism of myths.
Karl Popper

No rational argument will have a rational effect on a man who does not want to adopt a rational attitude.
Karl Popper

There is no history of mankind, there are only many histories of all kinds of aspects of human life. And one of these is the history of political power. This is elevated into the history of the world.
Karl Popper

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.
Karl Popper