Lives and Opinions of Eminent Philosophers

​A concept is a presentation of the intellect, being neither a particular entity nor a qualified object, but being as if an entity and as if a qualified object, such as the imprint of a horse which arises even when it is not present. A species is that which is comprehended by a genus, as human is comprehended by animal. The most generic is that which, being a genus, has no genus, such as "existent"; and the most specific is that which, being a species, has no species, like Socrates. Division is the cutting of a genus into its proximate species, for example: "Of animals, some are rational, and others irrational." Counter-division is the cutting of a genus into species according to opposition, as it were by negation, for example: "Of existents, some are good, and others not good." Subdivision is division upon division, for example: "Of existents, some are good, and others not good," and "Of things not good, some are bad, and others indifferent."

​Partition is the classification of a genus into areas, as Crinis says, for example: "Of goods, some pertain to the soul, and others to the body." Ambiguity is diction signifying two or even more things in expression, properly, and according to the same linguistic usage, so that multiple things are taken simultaneously under this diction; for example, "Auletris peptoke." For through this there is indicated, on the one hand, something such as "The house fell three times" (Aule tris), and on the other hand, something such as "The flute-girl fell" (Auletris). Dialectic is, as Posidonius says, the knowledge of things true, false, and neither; and this pertains, as Chrysippus says, to signifiers and things signified. In the inquiry concerning voice, then, such are the things said by the Stoics.

​In the topic concerning things and things signified, there is arranged the account concerning expressibles (lekta), both complete ones, propositions, and syllogisms, and that concerning incomplete ones, predicates, direct predicates, and passive predicates. They say that an expressible is that which subsists according to a rational presentation. Of expressibles, the Stoics say that some are complete, and others incomplete. Incomplete are those having an unfinished utterance, for example "He writes"; for we ask in addition, "Who?" Complete are those having a finished utterance, for example "Socrates writes." Among incomplete expressibles, then, are arranged predicates, while among complete ones are propositions, syllogisms, questions, and inquiries.

​A predicate is that which is asserted of something, or an attachable matter concerning someone or some things, as Apollodorus and his followers say, or an incomplete expressible attachable to a nominative case for the generation of a proposition. Of predicates, some are direct incidentals, such as "to sail through a rock." And of predicates, some are direct, some passive, and some neutral. Direct are those combined with one of the oblique cases for the generation of a predicate, for example "He hears," "He sees," "He converses." Passive are those combined with the passive particle, for example "I am heard," "I am seen." Neutral are those that are in neither condition, for example "He is prudent," "He walks." Reflexive are those among the passive which, while being passive in form, are actions, for example "He cuts his hair";

​for the one who cuts his hair includes himself. The oblique cases are genitive, dative, and accusative. A proposition is that which is true or false; or a complete matter declarative in so far as it depends on itself, as Chrysippus says in the Dialectical Definitions: "A proposition is that which is declarative or affirmative in so far as it depends on itself, for example 'It is day,' 'Dion walks.'" A proposition (axioma) is named from its being deemed worthy of assent (axiousthai) or rejected; for the one who says "It is day" seems to deem it worthy that it is day. When it is indeed day, the proposition set forth becomes true; but when it is not, it is false.