 Sentences proposed to the respondent split into “relevant” or “irrelevant” depending on their logical relation to preceding moves. If the sentence proposed to the respondent or its negation follows from preceding moves, it is relevant (pertinens) and should be either conceded (if implied by these moves) or negated (if it is incompatible with them); otherwise, it is irrelevant (impertinens). An irrelevant sentence is either conceded, negated, or doubted depending on the respondent’s knowledge about the “external” world; it is conceded if known to be actually true, negated if known to be actually false and doubted otherwise. Such a game is dynamic in the sense that the status of irrelevant sentences can change in the course of the game ([SCD] 1494: fol. 4ra–rb [1988a: 432–433]). This can happen for two reasons. First, if the external world changes during the game, the respondent’s move would change along with his new information state since the respondent’s moves regarding irrelevant sentences depend on his knowledge of the external world ([SCD] 1494: fol. 4rb [1988a: 433]). The second (and more interesting) case is brought about by the course of a particular game. Heytesbury’s example is the following game: