In his treatise ‘On Certainty’ (1969) L. Wittgenstein compared the propositions expressing basic principles to the hinges enabling both doubting and justifying knowledge. In 1985 Robert Fogelin proposed the conception of deep disagreement in argumentation analysis and in his description of it he referred to the hinges. We continue Wittgenstein’s hinges metaphor and compare pulling and pushing the door of knowledge to adopting contrary standings about principal issues, which can result in the deep disagreements. We suggest looking at the hinges enabling those door moves as at the fixed points in the extension semantic of the argumentation logic. Interpreting the hinges as the fixed points allows viewing rejected arguments as isolated deadlocks of the deep disagreements, or anti-extensions, and opens a possibility for a compromise on the basis of certain extensions.