Under him Avicenna read the Isagoge of Porphyry and the first propositions of Euclid.
Joachim Jung, in his Isagoge phytoscopica (1678), recognized that the plant-body consists of certain definite members, root, stem and leaf, and defined them by their different form and by their mutual relations.
He translated into Latin Aristotle's Analytica Priora et Posteriora, the Topica, and Elenchi Sophistici; and he wrote commentaries on Aristotle's Categories, on his book lrEpi Epµnvcias, also a commentary on the Isagoge of Porphyrius.
C. Meiser (Leipzig, 1877), and on Porphyry's Isagoge, ed.
A single sentence in Porphyry's Isagoge or " introduc tion " to the Categories of Aristotle furnished the i o, s text of the discussion.
In the Latin translation of Boetius, in which alone the Isagoge was then known, the sentence runs as follows: " Mox de generibus et speciebus illud quidem sive subsistant, sive in solis nudis intellectibus posita sint, sive subsistentia corporalia sint an incorporalia, et utrum separata a sensibilibus an in sensibilibus posita et circa haec consistentia, dicere recusabo; altissimum enim negotium est hujusmodi et majoris egens inquisitionis."
His pupil Richer has left us a detailed account of his system of teaching at Reims. So far as the trivium is concerned, his text-books were Victorinus's translation of Porphyry's Isagoge, Aristotle's Categories, and Cicero's Topics with Manlius's Commentaries.
Allgemeines historisches Lexikon (Leipzig, 1709 ff.); Historia Ecclesiastica Veteris Testamenti (4 vols., Halle, 1709); Elementa Philosophiae Practicae, Instrumentalis, et Theoreticae (3 vols., 1697); Selecta Juris Naturae et Gentium (Halle, 1704); Miscellanea Sacra (3 vols., Jena, 1727); and Isagoge Historico-Theologica ad Theologiam Universam, singulasque ejus pales (2 vols., 1727).
All that is wanting in his writings, especially in his Isagoge in artem analyticam (1591), in order to make them look like a modern school algebra, is merely the sign of equality - a want which is the more striking because Robert Recorde had made use of our present symbol for this purpose since 1 557, and Xylander had employed vertical parallel lines since 1575.
Sherburne states that Recorde also published Cosmographiae isagoge, and that he wrote a book De Arte faciendi Horologium and another De Usu Globorum et de Statu temporum.
Of the commentaries we have - (1) one on the Isagoge of Porphyry (Venice, 1500 fol.); (2) one on the Categories (Venice, 1503 fol.), the authenticity of which is doubted by Brandis; (3) one on the De Interpretatione (Venice, 1503 fol.).
It takes form as a body of doctrine drawing its premises from authority, sometimes in secular matters from that of Aristotle, but normally from that of the documents and traditions of systematic theology, while its method it draws from Aristotle, as known in the Latin versions,' mainly by Boethius, of some few treatises of the Organon together with the Isagoge of Porphyry.
Beside the theological and political works above quoted, Occam wrote Summa Logices (Paris, 1488, Oxford, 1675) commentaries on Porphyry's Isagoge, on the Categoriae, De Interpretatione and Elenchi of Aristotle.