Historicism, the belief that history follows discoverable laws toward an inevitable end, breeds totalitarian politics

Popper's central target is what he calls historicism: the view that history is governed by discoverable laws or trends that determine an inevitable future, whether that future is Plato's decay from an ideal state, Hegel's unfolding of the World Spirit, or Marx's progression through class struggle toward communism. This belief structure is politically dangerous regardless of which historical law is proposed, because if a thinker believes they've identified history's actual direction, anyone opposing that direction can be recast not as a legitimate rival but as an obstacle to an inevitable, cosmically sanctioned outcome, justifying suppression or violence as merely accelerating what was going to happen anyway. Popper contrasts historicism with genuine historical study, which can identify patterns without claiming they are iron laws guaranteeing a specific future, preserving room for human choice. He treats this distinction as the fault line separating open, pluralistic politics from closed, absolutist politics, regardless of whether the doctrine leans left or right. Takeaway: claiming to know history's destination, rather than any specific ideology, is the root of totalitarian justification.