We cannot reasonably aim at certainty

Three quotes from In Search of a Better World by Karl Popper.

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 science is never settled, just increasingly probably true.

There are uncertain truths — even true statements that we may take to be false — but there are no uncertain certainties.
Since we can never know anything for sure, it is simply not worth searching for certainty; but it is well worth searching for truth; and we do this chiefly by searching for mistakes, so that we have to correct them.

Passionate conviction does not lend itself to humble correction.

Why do I think that we, the intellectuals, are able to help? Simply because we, the intellectuals, have done the most terrible harm for thousands of years. Mass murder in the name of an idea, a doctrine, a theory, a religion — that is all our doing, our invention: the invention of the intellectuals. If only we would stop setting man against man — often with the best intentions — much would be gained. Nobody can say that it is impossible for us to stop doing this.

The pursuit of utopia depends on setting man against man. Ideologues are incapable of letting man be man, they have to fix people against their will. This contrasts with the promise of age of enlightenment classical liberalism which understood emergent order as a process by which people could, through their own self-interest, evolve towards a better world.