 Rules that prescribe how to explicitly bring forward local reasons are called the synthesis rules for local reasons. They are player-independent rules. A statement with an implicit reason (“!”) is challenged, and through this interaction the implicit local reasons are made explicit. For instance, the synthesis of local reasons for an implication (\(\varphi \supset \psi\)) is a challenge on the implication with implicit reason, where the challenger (\(\mathbf{Y}\)) states the antecedent (\(\varphi\)) with an explicit reason of his choice (\(p_1)\), and the defender (\(\mathbf{X}\)) states the consequent (\(\psi)\) with an explicit reason of his choice (\(p_2)\):