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.

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.

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

Some scientists find, or so it seems, that they get their best ideas when smoking; others by drinking coffee or whisky. Thus there is no reason why I should not admit that some may get their ideas by observing, or by repeating observations.

It is not his possession of knowledge, of irrefutable truth, that makes the man of science, but his persistent and recklessly critical quest for truth.

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.

Almost everyone... seems to be quite sure that the differences between the methodologies of history and of the natural sciences are vast. For, we are assured, it is well known that in the natural sciences we start from observation and proceed by induction to theory. And is it not obvious that in history we proceed very differently? Yes, I agree that we proceed very differently. But we do so in the natural sciences as well.