The history of science, like the history of all human ideas, is a history of irresponsible dreams, of obstinacy, and of error.

It is the rule which says that the other rules of scientific procedure must be designed in such a way that they do not protect any statement in science against falsification.

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.

We never know what we are talking about.

[To] interpret Parmenides as a Kant before Kant ... this is exactly what we must do.

Simple statements are to be prized more highly than less simple ones because they tell us more; because their empirical content is greater; and because they are better testable.

It is wrong to ask who will rule. The ability to vote a bad government out of office is enough. That is democracy.