Performative contradiction are performative contradictions in this context. Habermas claims that post-modernism's epistemological relativism suffers from a performative contradiction. Hans-Hermann Hoppe claims in his theory of argumentation ethics that arguing for any political position other than free-market anarchism results in a performative contradiction. Jaakko Hintikka more rigorously fleshed out the notion of performative contradiction in analyzing Descartes' famous "cogito ergo sum" argument, concluding that "cogito ergo sum" relies on performance rather than logical inference. Performative contradiction A performative contradiction () arises when the propositional content of a statement contradicts the presuppositions of asserting it. An example of a performative contradiction is the
Cogito, ergo sum the "I" from the thinking thing. Here, the "cogito" has already assumed the "I"'s existence as that which thinks. For Kierkegaard, Descartes is merely "developing the content of a concept", namely that the "I", which already exists, thinks. As Kierkegaard argues, the proper logical flow of argument is that existence is already assumed or presupposed in order for thinking to occur, not that existence is concluded from that thinking. Bernard Williams claims that what we are dealing with when we talk of thought, or when we say "I am thinking," is something conceivable from a third-person perspective; namely objective "thought-events"