 A different device comes into play for modal judgments of possibility and necessity (II.8). Verbal propositions including modal terms such as “possible” and “necessary” express mental propositions in which the basic acts of affirmation and denial are modified. The ideas entering into modal propositions are not themselves modified (Van der Scharr 2008: 334–335; Marušić 2014: 277–278). The authors label such acts “tacit” or “virtual” affirmations (II.7, 93). It seems open to the authors to regard such complex thoughts as conditionals, conjunctions, and disjunctions as similarly involving modified affirmations, but they do not explicitly endorse this strategy.