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.

Every genuine test of a theory is an attempt to falsify it, or to refute it.

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.

Criticism of my alleged views was widespread and highly successful. I have yet to meet a criticism of my views.

The initial stage, the act of conceiving or inventing a theory, seems to me neither to call for logical analysis nor to be susceptible of it.

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.

Propose theories which can be criticized. Think about possible decisive falsifying experiments-crucial experiments. But do not give up your theories too easily-not, at any rate, before you have critically examined your criticism.