If you know that things are bound to happen whatever you do, then you may feel free to give up the fight against them.
Evolution is not a fact. Evolution doesn’t even qualify as a theory or as a hypothesis. It is a metaphysical research program, and it is not really testable science.
The growth of knowledge depends entirely upon disagreement.
The war of ideas is a Greek invention. It is one of the most important inventions ever made. Indeed, the possibility of fighting with with words and ideas instead of fighting with swords is the very basis of our civilization, and especially of all its legal and parliamentary institutions.
The best thing that can happen to a human being us to find a problem, to fall in love with that problem, and to live trying to solve that problem, unless another problem even more lovable appears.
It is not possible to write clearly enough to avoid being misrepresented by people who are sufficiently determined to do so.
It can’t happen here is always wrong: a dictatorship can happen anywhere.
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.
The attempt to make heaven on earth invariably produces hell.
The difference between the amoeba and Einstein is that, although both make use of the method of trial and error elimination, the amoeba dislikes erring while Einstein is intrigued by it.
A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others – not by simply taking over another’s opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others.
It is impossible to speak in such a way that you cannot be misunderstood.
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.
All we can do is search for the falsity content in our best theory.
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.
Whenever we propose a solution to a problem, we ought to try as hard as we can to overthrow our solution, rather than defend it.
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.
The use of violence is justified only under a tyranny which makes reforms without violence impossible, and should have only one aim, that is, to bring about a state of affairs which makes reforms without violence possible.
Every solution of a problem raises new unsolved problems.
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.