Online research in philosophy

“Aristotle's successor as director of the Lyceum was Theophrastus, his friend and disciple; Eudemus, another of the Stagirite's important disciples should also be mentioned. Other philosophers belonging to the Peripatetic school were: Aristoxenus, Dikaiarchos, Phanias, Straton, Duris, Chamaeleon, Lycon, Hieronymus, Ariston, Critolaus, Phormio, Sotion, Hermippus, Satyrus and others. Straton even succeeded Theophrastus as director of the Lyceum but his name and those of the other Peripatetics of Aristotle's old school should not be considered in a history of logic as (...) they were mainly concerned with history and the natural sciences. Theophrastus rejoiced in an enormous prestige at this time and for long afterwards. Diogenes Laertius attributes a tremendous number of works to him. Of them a significant proportion are writings on logic: Analytica Priora (3 books); Analytica Posteriora (7 books); Analysis of Syllogisms (1 book); Summary of the Analytic s (1 book); Polemic on the Theory of Euristic Arguments. On Definition (1 book); The First Premises (18 books); The Sophisms (2 books); On the Solution of Syllogisms (1 book); Topics (2 books); On Artless Demonstrations (1 book); On Negation (1 book); On Intellect (1 book); Classifications (2 books); On Entymemes (1 book); On the Appreciation of Syllogism (1 book); On Lies and Truth (1 book); Argumentations (2 books); Theses (3 books); On Definition (2 books); On the Data of Problems (1 book); On the Liar (3 books); Preface to the Topics (1 book); On Arguments proper (1 book); Specifications on The Texts of Syllogisms (1 book). Eudemus also wrote some treatises on logic, concerning which some information has come down to us; Ammonius, in his Commentary On Aristotle's Categories attributes to him a writing on The Analytics -- 'Analitika', and another On Expressions -- Peri lexeos, in which he deals with the grammatical and logical functions of the sentence. The commentator David in Prolegomena to Isagoge by Porphiry also mentions these works.. (shrink)

ABSTRACT: This paper traces the evidence in Galen's Introduction to Logic (Institutio Logica) for a hypothetical syllogistic which predates Stoic propositional logic. It emerges that Galen is one of our main witnesses for such a theory, whose authors are most likely Theophrastus and Eudemus. A reconstruction of this theory is offered which - among other things - allows to solve some apparent textual difficulties in the Institutio Logica.

Logic as a discipline starts with the transition from the more or less unreflective use of logical methods and argument patterns to the reflection on and inquiry into these and their elements, including the syntax and semantics of sentences. In Greek and Roman antiquity, discussions of some elements of logic and a focus on methods of inference can be traced back to the late 5th century BCE. The Sophists, and later Plato (early 4th c.) displayed an interest in sentence analysis, (...) truth, and fallacies, and Eubulides of Miletus (mid-4th c.) is on record as the inventor of both the Liar and the Sorites paradox. But logic as a fully systematic discipline begins with Aristotle, who systematized much of the logical inquiry of his predecessors. His main achievements were his theory of the logical interrelation of affirmative and negative existential and universal statements and, based on this theory, his syllogistic, which can be interpreted as a system of deductive inference. Aristotle's logic is known as term-logic, since it is concerned with the logical relations between terms, such as ‘human being’, ‘animal’, ‘white’. It shares elements with both set theory and predicate logic. Aristotle's successors in his school, the Peripatos, notably Theophrastus and Eudemus, widened the scope of deductive inference and improved some aspects of Aristotle's logic. (shrink)

In the "Doxographi Graeci" the preferred short heading of Aët. 2.31 (Greek text below, p. 28) is 'On Distances', though ps.Plutarch has a long heading. This chapter is about the distances of the sun and moon from each other and from the earth (lemmas 1 to 3, in both ps.Plutarch and Stobaeus), and of the real or apparent shape of the heaven relative to its distance from the earth (lemmas 4 and 5, Stobaeus only). Parallels from Ioann. Lydus and Theodoret (...) for what is in ps.Plutarch are given by Diels in apparatu. To the best of my knowledge it has not been noticed that a version of ps.Plutarch's text is preserved in a scholium on the "Almagest", which constitutes our earliest evidence for the text. The correctness of Diels' reconstruction is questionable. Though certainty, naturally, is beyond our reach it is quite possible that these two sets of lemmas represent two distinct Aëtian (or proto-Aëtian) chapters. These may have been coalesced by Stobaeus (or Aëtius), while ps.Plutarch abridged the second (or the two final lemmas) away. These considerations necessitate an inquiry into the parallels that are available, including material from an introduction to Aratus. The vexing question of short versus long(er) chapter headings is also relevant in this context. Furthermore, the contrasting views regarding cosmic distances are not only a feature of the Placita literature with a distant origin in Aristotle, but also, apparently, of the commentary literature on Plato's "Timaeus". Arguably in a passage in Plutarch's "De facie" these two traditions intersect. Finally, a case can be made out for Eudemus not Theophrastus as an intermediary source of Presocratic astronomical data in the Placita. (shrink)