The origin of the opposition πτωσις όρθη (ευθεια) - πτωσεις πλαγιαι (casus rectus - casus obliqui) in the linguistics of ancient Greece

The opposition ptw'si" ojrqhv (eujqei'a) / ptwvsei" plavgiai, which with time began to expressthe contrast between the nominative and the oblique cases (casus rectus – casus obliqui) inthe grammatical tradition, first appeared in the Greek reflection on language most probably inthe circle of the Stoic doctrine, where it was used to determine the meanings of nouns perceivedfrom the point of view of their constituting elements of the predicative-argumentativestructures which formed propositions (ajxiwvmata). What justifies this statement is the fact thatin the framework of the Stoic dialectics concepts denoted by terms ojrqhv ptw'si" andplavgiai ptwvsei" were unambiguously situated in the sphere of the linguistically expressedcontent (ta; shmainovmena, ta; lektav) and used consistently in connection with the concept ofkathgovrhma (‘predicate’), that is the predicative content expressed by the verb. The analysisof the preserved records demonstrates that the term ojrqh; ptw'si" had a meaning of the subjectivepredicate argument (disregarding the value of the case of the noun which denoted it),whereas ptwvsei" plavgiai had the meaning of the non-subjective arguments implied bymulti-argument predicates. Therefore, in the Stoic dialectics the opposition ojrqh; ptw'si" /plavgiai ptwvsei" reflected the hierarchical differentiation of the status of the content expressedby the nouns perceived as arguments of the predicate within the proposition. Theseterms gained the meaning of the nominative and the oblique cases, respectively, only in thecircle of Hellenistic philologists, whose research and analyses were to a greater extent focusedon the formal side of linguistic signs (words). Those scholars used the terminological apparatusof the Stoic school, while introducing there some vital modifications, however. Withreference to the issue which interests us here, the modification consisted in the identificationof the Stoic ojrqh; ptw'si" with its most frequent language exponent, i.e. the noun in the nominative,and following the same principle, of the Stoic plavgiai ptwvsei" with nouns in theoblique cases. The Hellenistic philological school should probably also be ascribed the introductionof the term eujqei'a ptw'si" as a name of the nominative synonymous withojrqh; ptw'si", as there are no sufficient premises on which to attribute the use of the adjectiveeujquv" as an index of that case already to Aristotle.