  Assertibles are simple or non-simple. A simple predicative assertible like ‘Dion is walking’ is generated from the predicate ‘is walking’, which is a deficient assertible since it elicits the question ‘who?’, together with a nominative case (Dion’s individual quality or the correlated sayable), which the assertible presents as falling under the predicate (D. L. 7.63 and 70). There is thus no interchangeability of predicate and subject terms as in Aristotle; rather, predicates—but not the things that fall under them—are defined as deficient, and thus resemble propositional functions. It seems that whereas some Stoics took the—Fregean—approach that singular terms had correlated sayables, others anticipated the notion of direct reference. Concerning indexicals, the Stoics took a simple definite assertible like ‘this one is walking’ to be true when the person pointed at by the speaker is walking (S. E. M 100). When the thing pointed at ceases to be, so does the assertible, though the sentence used to express it remains (Alex. Aphr. An. Pr. 177–8). A simple indefinite assertible like ‘someone is walking’ is said to be true when a corresponding definite assertible is true (S. E. M 98). Aristotelian universal affirmatives (‘Every A is B’) were to be rephrased as conditionals: ‘If something is A, it is B’ (S. E. M 9.8–11). Negations of simple assertibles are themselves simple assertibles. The Stoic negation of ‘Dion is walking’ is ‘(It is) not (the case that) Dion is walking’, and not ‘Dion is not walking’. The latter is analyzed in a Russellian manner as ‘Both Dion exists and not: Dion is walking’ (Alex. Aphr. An. Pr. 402). There are present tense, past tense and future tense assertibles.  The—temporalized—principle of bivalence holds for them all. The past tense assertible ‘Dion walked’ is true when there is at least one past time at which ‘Dion is walking’ was true.