 These kinds of question have played a major role in the scientific realism debate. The challenge to scientific realism is supposed to come directly from the history of science. The history of science, it is claimed, is at odds with scientific realism’s epistemic optimism. It is full of theories which were shown to be false and abandoned, despite their empirical successes. Hence, it is claimed, realists cannot be warrantedly optimistic about the (approximate) truth of currently empirically successful theories. If we take the historical evidence seriously, it is claimed, current theories too will, sooner or later, be abandoned and take their place in future history-of-science courses. This anti-realist line of argument has become known as ‘the pessimistic induction’ (aka pessimistic meta-induction)—henceforth PI. Without denying that theories change over time, scientific realists have tried to block this line of argument by showing either that it is fallacious or that there is substantive continuity in theory-change which warrants the realist’s optimism that current science is on the right track.