Stoic Logic of Language With Chrysippus and Beyond

• Applicant: Dr. Karlheinz Hülser
• Subject Area: History of Philosophy
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 450927166

In 1935 Łukasiewicz convinced the scientific community that Stoic logic in comparison with Aristotelian logic would be significantly different. Hence, intensive investigations started, mainly since the nineteen-sixties and after. In view of the fragmentary sources the research work was so effective that remaining questions very often appear to recede into the background. During the last years, however, the studies in Stoic dialectics re-emerged. The project »Stoic Logic of Language With Chrysippus and Beyond« joins in the Stoics' understanding of predicates, studying its development beyond Chrysippus. Thus, it shows how the analytical approach to the question of the constitution of objects changed in Stoicism, until modern logic could pick it up, together with its difficulties.The project relies on two pillars: one, the Stoic definitions, and connected explanations, of the predicate. This material challenges to demonstrate that concerning the understanding of predi-cates there was a development in doctrine within the Stoa. Two, to clarify the developmental scope, unrelated distinctive positions will be discussed; they related to detailed issues, and were developed in the Stoa, partly already before Chrysippus, partly by Chrysippus himself. Just these positions, yet, required further consideration, and post-Chrysippean Stoic logicians presumably tried to surpass those positions. In all cases, however, adequate revisions would require to modify the concept of predicate somehow, in that very direction shown by one of the respective Stoic definitions. In detail the issues or views under discussion will be: the doubts Zeno of Citium developed against the rule that in the lawcourt before forming a judgment both of the parties should be heard; Chrysippus' dissatisfying analysis of deictic demonstrative pronouns and the Stoic division of propositions; Chrysippus' hesitation to use quantifiers, and to interprete by me-ans of his logic also Aristotelian syllogisms; and schemata of arguments.Having elaborated the two ›pillars‹ as indicated, the findings will be brought together. Therewith it will be possible (a) to specify the development concerning predicates, regarding time and content, (b) to explain in greater detail how to conceive the revising processes of the ›pillar-2‹ positions, and (c) to collect some added value, e.g. a closer understanding of the Stoics' view on universals. In addition, (d) it will be possible not only to demonstrate the affinity of the post-chrysippean predicate-concept to Fregee's concept of function, but also to examine Frege's related concept of argument in the light of the Stoic concept of cases. It is here, at the latest, that the question arises what the Stoic and what the modern logic have to say about the constitution of objects.

• DFG Programme: Research Grants