 This rule is also importantly connected to the topic of the dialogical account of formality  (Section 2.1.3)  and, for that reason, to some critics against the framework on the relation between formality and content which are discussed in  Section 3.  In the standard dialogical framework, the only elements whose meaning is left unspecified in formal plays are the elementary statements. The Formal Rule ensures that, in order to back the thesis, the proponent is not bringing in any elementary statement that the opponent might not agree with: the proponent can only back his thesis with elementary statements that the opponent herself has already stated. Recent developments of the framework, as discussed in  Section 3.2,  allow the opponent to challenge elementary statements; the proponent then needs to specify on what ground he makes this statement, thus giving rise to material dialogues where the meaning of elementary statements is analysed more deeply than in the standard, formal dialogues.