Porphyry (philosopher)
Porphyry of Tyre (; , "Porphýrios"; , "Furfūriyūs"; – ) was a Tyrian Neoplatonic philosopher born in Tyre, Roman Syria during Roman rule. He edited and published "The Enneads", the only collection of the work of Plotinus, his teacher. His commentary on Euclid's "Elements" was used as a source by Pappus of Alexandria. He wrote original works in the Greek language on a wide variety of topics, ranging from music theory to Homer to vegetarianism. His "Isagoge", or "Introduction", an introduction to logic and philosophy, was the standard textbook on logic throughout the Middle Ages in its Latin and Arabic translations. Through  works such as "Philosophy from Oracles" and "Against the Christians" (which was banned by Constantine the Great), he was involved in a controversy with early Christians. Biography. The "Suda" (a 10th-century Byzantine encyclopedia based on many sources now lost) reports that Porphyry was born in Phoenician city of Tyre. His parents named him "Malchus" ("king" in the Semitic languages) but his teacher in Athens, Cassius Longinus, gave him the name Porphyrius ("clad in purple"), possibly a reference to his Phoenician heritage, or a punning allusion to his name and the color of royal robes. Under Longinus he studied grammar  and rhetoric. In 262 he went to Rome, attracted by the reputation of Plotinus, and for six years devoted himself to the practice of Neoplatonism, during which time he severely modified his diet. At one point he became suicidal. On the advice of Plotinus he went to live in Sicily for five years to recover his mental health. On returning to Rome, he lectured on philosophy and completed an edition of the writings of Plotinus (who had died in the meantime) together with a biography of his teacher. Iamblichus is mentioned in ancient Neoplatonic writings as his pupil, but this  most likely means only that he was the dominant figure in the next generation of philosophers. The two men differed publicly on the issue of theurgy. In his later years, he married Marcella, a widow with seven children and an enthusiastic student of philosophy. Little more is known of his life, and the date of his death is uncertain. Section::::"Introduction" ("Isagoge"). Porphyry is best known for his contributions to philosophy. Apart from writing the "Aids to the Study of the Intelligibles" (Ἀφορμαὶ πρὸς τὰ νοητά; "Sententiae Ad Intelligibilia Ducentes"), a basic summary of Neoplatonism, he is especially appreciated for his  Introduction to Categories ("Introductio in Praedicamenta" or "Isagoge et in Aristotelis Categorias commentarium"), a very short work often considered to be a commentary on Aristotle's "Categories", hence the title. According to , however, the correct title is simply "Introduction" (Εἰσαγωγή "Isagoge"), and the book is an introduction not to the "Categories" in particular, but to "logic" in general, comprising as it does the theories of predication, definition, and proof. The Introduction describes how qualities attributed to things may be classified, famously breaking down the philosophical concept of substance into the five components "genus", "species", "difference", "property", "accident". As Porphyry's  most influential contribution to philosophy, the "Introduction to Categories" incorporated Aristotle's logic into Neoplatonism, in particular the doctrine of the categories of being interpreted in terms of entities (in later philosophy, "universal"). Boethius' "Isagoge", a Latin translation of Porphyry's "Introduction", became a standard medieval textbook in European schools and universities, which set the stage for medieval philosophical-theological developments of logic and the problem of universals. In medieval textbooks, the all-important "Arbor porphyriana" ("Porphyrian Tree") illustrates his logical classification of substance. To this day, taxonomy benefits from concepts in Porphyry's Tree, in classifying living organisms (see  cladistics). The "Introduction" was translated into Arabic by Abd-Allāh Ibn al-Muqaffaʿ from a Syriac version. With the Arabicized name "Isāghūjī" (إيساغوجي) it long remained the standard introductory logic text in the Muslim world and influenced the study of theology, philosophy, grammar, and jurisprudence. Besides the adaptations and epitomes of this work, many independent works on logic by Muslim philosophers have been entitled Isāghūjī. Porphyry's discussion of "accident" sparked a long-running debate on the application of "accident" and "essence". Section::::"Philosophy from Oracles" ("De Philosophia ex Oraculis Haurienda"). Porphyry is also known as an opponent of Christianity and  defender of Paganism; his precise contribution to the philosophical approach to traditional religion may be discovered in the fragments of "Philosophy from Oracles" (Περὶ τῆς ἐκ λογίων φιλοσοφίας; "De Philosophia ex Oraculis Haurienda"), which was originally three books in length. There is debate as to whether it was written in his youth (as Eunapius reports) or closer in time to the persecutions of Christians under Diocletian and Galerius. Whether or not Porphyry was the pagan philosopher opponent in Lactantius' "Divine Institutes", written at the time of the persecutions, has long been discussed. The fragments of the "Philosophy from Oracles" are  only quoted by Christians, especially Eusebius, Theodoret, Augustine, and John Philoponus. The fragments contain oracles identifying proper sacrificial procedure, the nature of astrological fate, and other topics relevant for Greek and Roman religion in the third century. Whether this work contradicts his treatise defending vegetarianism, which also warned the philosopher to avoid animal sacrifice, is disputed among scholars. Section::::"Against the Christians" ("Adversus Christianos"). During his retirement in Sicily, Porphyry wrote "Against the Christians" (Κατὰ Χριστιανῶν; "Adversus Christianos") which consisted of fifteen books. Some thirty Christian apologists, such as Methodius, Eusebius, Apollinaris, Augustine, Jerome, etc., responded to his challenge. In fact , everything known about Porphyry's arguments is found in these refutations, largely because Theodosius II ordered every copy burned in AD 435 and again in 448. Augustine and the 5th-century ecclesiastical historian Socrates of Constantinople, assert that Porphyry was once a Christian. Other subjects. Porphyry was opposed to the theurgy of his disciple Iamblichus. Much of Iamblichus' mysteries is dedicated to the defense of mystic theurgic divine possession against the critiques of Porphyry. French philosopher Pierre Hadot maintains that for Porphyry, spiritual exercises are an essential part of spiritual development. Porphyry was, like Pythagoras, an advocate of vegetarianism on  spiritual and ethical grounds. These two philosophers are perhaps the most famous vegetarians of classical antiquity. He wrote the "" (Περὶ ἀποχῆς ἐμψύχων; "De Abstinentia ab Esu Animalium"), advocating against the consumption of animals, and he is cited with approval in vegetarian literature up to the present day. Porphyry also wrote widely on music theory, astrology, religion, and philosophy. He produced a "History of Philosophy" ("Philosophos historia") with "vitae" of philosophers that included a life of his teacher, Plotinus. His life of Plato from book iv exists only in quotes by Cyril of Alexandria. His book "Vita Pythagorae" on the life  of Pythagoras is not to be confused with the book of the same name by Iamblichus. His commentary on Ptolemy's "Harmonics" ("Eis ta Harmonika Ptolemaiou hypomnēma") is an important source for the history of ancient harmonic theory. Porphyry also wrote about Homer. Apart from several lost texts known only from quotations by other authors, two texts survive at least in large parts: the "Homerian Questions" ("Homēriká zētḗmata", largely a philological comment on the Iliad and Odyssey) and "On the Cave of the Nymphs in the Odyssey" ("Peri tou en Odysseia tōn nymphōn antrou").