We do not know. We can only guess..

Every intellectual has a very special responsibility. He has the privilege and the opportunity of studying. In return, he owes it to his fellow men (….

Every solution of a problem raises new unsolved problems..

If we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with ….

The only way to test a hypothesis is to look for all the information that disagrees with it..

You cannot have a rational discussion with a man who prefers shooting you to being convinced by you..

Optimism is a duty. The future is open. It is not predetermined. No one can predict it, except by chance. We all contribute to determining it by what….

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 rea….

I personally call the type of government which can be removed without violence 'democracy,' and the other, 'tyranny.'..

It is not possible to write clearly enough to avoid being misrepresented by people who are sufficiently determined to do so..

Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not pre….

Those who promise us paradise on earth never produced anything but a hell..

All life is problem solving.

I remained a socialist for several years, even after my rejection of Marxism; and if there could be such a thing as socialism combined with individua….

Ignorance is not a simple lack of knowledge but an active aversion to knowledge, the refusal to know, issuing from cowardice, pride, or laziness of m….

It can't happen here is always wrong: a dictatorship can happen anywhere..

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

The question is not how to get good people to rule; THE QUESTION IS: HOW TO STOP THE POWERFUL from doing as much damage as they can to us..

If you can't say it simply and clearly, keep quiet, and keep working on it till you can..

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, un….

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 w….