Hermann Cohen's Logic of Pure Knowledge and G. W. F. Hegel's Science of Logic each use in their way the means of thought of negation and contradiction to unfold the philosophical dynamic: a fragile interplay between self-endangerment and self-preservation of thought. Here, the proximity and difference of the two authors are extended. The proximity lies in methodological negativism. The difference is in the significance of the principle of continuity. According to Cohen and Hegel as well, thinking proceeds exclusively, as Kant called it, synthetically. The exclusion of contradiction, limited to analytical judgments, has only marginal significance. But the commonality does not eliminate the differences. As Hegel puts it, contradiction is a principle of mediation and finally results in "self-dissolution"; it carries within itself a direction of logical "reconciliation." Per Cohen, contradiction is a principle of "annihilation" (annihilatio) of approaches to a determination that threatens any form of "identity." The turn Hegel put in contradiction itself, regarding in it a unity of positivity and negativity, has no direct counterpart in Cohen. Nevertheless, for him, too, the "judgment of contradiction" becomes the active basis of all cognitive thought. By exercising a contradiction-destroying "activity," the judgment of contradiction "protects," indeed "generates," the real possibility of cognition. The annihilation of the non-identical sets free the fundamental "judgment of origin" with which cognition finds its beginning. The principle of continuity taken over from Leibniz corresponds to it. Just this principle has now again no direct correspondence with Hegel.