In previous articles, it has been shown that the deductive system developed by Aristotle in his "second logic" is a natural deduction system and not an axiomatic system as previously had been thought. It was also stated that Aristotle's logic is self-sufficient in two senses: First, that it presupposed no other logical concepts, not even those of propositional logic; second, that it is (strongly) complete in the sense that every valid argument expressible in the language of the system is deducible (...) by means of a formal deduction in the system. Review of the system makes the first point obvious. The purpose of the present article is to prove the second. Strong completeness is demonstrated for the Aristotelian system. (shrink)

v. 1. The ethical treatises, being the treatises of the first Ennead with Porphyry's Life of Plotinus, and the Preller-Ritter extracts forming a conspectus of the Plotinian system. Psychic and physical treatises; comprising the second and third Enneads.--v. 2. On the nature of the soul [being the foruth Ennead] The divine mind, being the treatises of the fifth Ennead. On the One and Good being the treatises of the sixth Ennead.

In Proclus' penetrating exposition of Euclid's method's and principles, the only one of its kind extant, we are afforded a unique vantage point for understanding the structure and strenght of the Euclidean system. A primary source for the history and philosophy of mathematics, Proclus' treatise contains much priceless information about the mathematics and mathematicians of the previous seven or eight centuries that has not been preserved elsewhere.

Proclus, head of the Philosophy School at Athens for fifty years, was one of the leading philosophical figures in Late Antiquity. Lucas Siorvanes here introduces Proclus to English-language readers, discussing his metaphysics and theory of knowledge and focusing in particular on his Neo-Platonism. Proclus lived in the turbulent fifth century A.D., a time of struggles among Christians, Jews, and pagans, the invasion of Attila the Hun, the fall of the Western Roman Empire, and the rise of the Eastern Roman Empire (...) in Byzantium. While Late Antiquity has been regarded as a time of superstition and forbiddingly complex philosophies, recent scholarship has shown it to be full of cultural and intellectual vigor. During Proclus's tenure as head of the Philosophy School, he systematized Neo-Platonism as the summit of ancient Greek thought, brought it to its peak of influence, and became responsible for the form in which it was transmitted to the Byzantine, Western European, and Islamic civilizations. Siorvanes's extensive original research presents Proclus as much more than just a metaphysician. He surveys all of Proclus's philosophical interests—including religion, physics, astronomy, mathematics, and poetry—revealing the philosopher's central concern with the problems of being and knowledge and relating the ideas of Proclus to those of such other major thinkers as Plato, Aristotle, and Ptolemy. To help the newcomer, Siorvanes supplies more than 200 quotations from Proclus's works. He also traces the impact of Proclus's Neo-Platonism across cultures, religions, and centuries, in such diverse areas as Christian and Islamic theologies, Renaissance art, Kepler's astronomy, Romantic poetry, Emerson's thought, modern philosophy and science, and current popular phrases. (shrink)

John Corcoran’s natural deduction system for Aristotle’s syllogistic is reconsidered.Though Corcoran is no doubt right in interpreting Aristotle as viewing syllogisms as arguments and in rejecting Lukasiewicz’s treatment in terms of conditional sentences, it is argued that Corcoran is wrong in thinking that the only alternative is to construe Barbara and Celarent as deduction rules in a natural deduction system.An alternative is presented that is technically more elegant and equally compatible with the texts.The abstract role assigned by tradition and Lukasiewicz (...) to Barbara and Celarent is retained.The two ‘ perfect syllogisms’ serve as ‘basic elements’ in the construction of an inductively defined set of valid syllogisms.The proposal departs from Lukasiewicz, and follows Corcoran, however, in construing the construction as one in natural deduction.The result is a sequent system with fewer rules and in which Barbara and Celarent serve as basic deductions.To compare the theory to Corcoran’s, his original is reformulated in current terms and generalized.It is shown to be equivalent to the proposed sequent system, and several variations are discussed.For all systems mentioned, a method of Henkin‐style completeness proofs is given that is more direct and intuitive than Corcoran’s original. (shrink)

" It is the connected presentation of Jespersen's views of the general principles of grammar based on years of studying various languages through both direct ...

This is the first English translation of Proclus' commentary on Plato's Parmenides. Glenn Morrow's death occurred while he was less than halfway through the translation, which was completed by John Dillon. A major work of the great Neoplatonist philosopher, the commentary is an intellectual tour de force that greatly influenced later medieval and Renaissance thought. As the notes and introductory summaries explain, it comprises a full account of Proclus' own metaphysical system, disguised, as is so much Neoplatonic philosophy, in the (...) form of a commentary. (shrink)

The paper is a study of the logic of existence, negation, and order in the Neoplatonic tradition. The central idea is that Neoplatonists assume a logic in which the existence predicate is a comparative adjective and in which monadic predicates function as scalar adjectives that nest the background order. Various scalar predicate negations are then identifiable with various Neoplatonic negations, including a privative negation appropriate for the lower orders of reality and a hyper-negation appropriate for the higher. Reversion to the (...) One can then be explained as the logical inference of hyper-negations from mundane knowledge. Part I develops the relevant linguistic and logical theory, and Part II defends Wolfson and the scalar interpretation against the more traditional Aristotelian understanding of Whittaker and others of reversion as intensional abstraction. (shrink)