We must plan for freedom, and not only for security, if for no other reason than that only freedom can make security secure
We all remember how many religious wars were fought for a religion of love and gentleness; how many bodies were burned alive with the genuinely kind intention of saving souls from the eternal fire of hell
It is impossible to speak in such a way that you cannot be misunderstood.
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
It seems to me certain that more people are killed out of righteous stupidity than out of wickedness.
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.
Our aim as scientists is objective truth; more truth, more interesting truth, more intelligible truth. We cannot reasonably aim at certainty. Once we realize that human knowledge is fallible, we realize also that we can never be completely certain that we have not made a mistake.
Science may be described as the art of systematic over-simplification.
You can choose whatever name you like for the two types of government. I personally call the type of government which can be removed without violence democracy, and the other tyranny.
Piecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology.
The game of science is, in principle, without end. 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.
Do not allow your dreams of a beautiful world to lure you away from the claims of men who suffer here and now. Our fellow men have a claim to our help; no generation must be sacrificed for the sake of future generations, for the sake of an ideal of happiness that may never be realised.
The open society is one in which men have learned to be to some extent critical of taboos, and to base decisions on the authority of their own intelligence.
No rational argument will have a rational effect on a man who does not want to adopt a rational attitude.
Science must begin with myths, and with the criticism of myths.