The defence of democracy must consist in making anti-democratic experiences too costly for those who try them; much more costly than a democratic compromise

Science is perhaps the only human activity in which errors are systematically criticized and, in time, corrected.

There is no history, only histories.

My thesis is that what we call 'science' is differentiated from the older myths not by being something distinct from a myth, but by being accompanied by a second-order tradition-that of critically discussing the myth. ... In a certain sense, science is myth-making just as religion is.

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.

The attempt to make heaven on earth invariably produces hell.

Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society, then the tolerant will be destroyed, and tolerance with them. We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.