Whenever we are dealing with an “official” progressive succession of philosophers, the truly interesting thing is to consider how a philosopher who was, according to this “official line,” “overcome” or “completed” by his successor(s), reacts to his successor(s)…

What is the philosophical status of these “retroactive” rejoinders? … They do not so much undermine the underlying line of succession … as, rather, bring forth its most interesting and lively moment, the moment when, as it were, a thought rebels against its reduction to a term in the chain of “development” and asserts its absolute right or claim… That is to say, when the Old is attacked by the New, this first appearance of the New is as a rule flat and naïve—the true dimension of the New arises only when the Old reacts to the (first appearance of) the New. Pascal reacted from a Christian standpoint to scientific secular modernity, and his “reaction” … tells us much more about modernity than its direct partisans. The true “progress” emerges from the reaction of the Old to the progress. True revolutionaries are always reflected conservatives.

— Slavoj Zizek, “Fichte’s Laughter,” in Mythology, Madness, and Laughter: Subjectivity in German Idealism, pp. 122-123.