 The Formal Rule accounts for analyticity: the proponent, who brings the thesis forward, will have to defend it without bringing any elementary statement (i.e., without introducing any new atomic formula) of his own in the play. His defence of the thesis will have to rely only on the elementary statements of the opponent. What is more, everything the opponent states comes only from her challenges of the proponent’s statements (especially the thesis), so that the opponent’s statements proceed from the meaning of the thesis (or, in some cases, her own initial concessions—see  Section 3.2  for examples of dialogues with concessions).