Let me start by defining “theory,” because the definition itself illustrates why we can name hegel as its inventor, rather than marx or Nietzsche, both of whom pick up where Hegel left off. As I suggest in The Birth of Theory, Hegel founds theory in his break from Kant, which I regard as the signal moment when philosophy transforms into theory as we now know it. What makes Hegel different from Kant, in other words, is what makes his habits of thought— his dialectic, above all—lasting and familiar and such a part of what goes into critical theorizing today, even within schools of thought that celebrate their anti-Hegelianism or are indifferent to Hegel. In Hegel we find the following three features that I am content to call “theory.”