Historia Filosofica De Oriente

The first scholarch was Speusippus, the nephew of Plato, who, according to Diogenes Laertius,{1} received his appointment from Plato himself. He in turn was succeeded by Xenocrates,{2} and in this manner the succession of scholarchs continued down to the sixth century of the Christian era.{3}

It is customary to distinguish in the history of the Platonic school three periods, known as the Old, the Middle, and the New Academy. To the Old Academy belonged Speusippus, Xenoerates, Heraclides of Pontus, Philip of Opus, Crates, and Crantor; Arcesilaus and Carneades are the principal representatives of the Middle Academy, while Philo of Larissa and Antiochus of Ascalon are the best-known members of the New Academy.

Sources. Our sources of information concerning the history of the doctrines of the three Academies are for the most part secondary; they are scanty and cannot be relied upon in matters of detail. As far, however, as a general characterization of each school is concerned, our materials are sufficiently ample and trustworthy.

Old Academy. The Old Academy flourished from the death of Plato (347 B.C.) until the appearance of Arcesilaus as scholarch (about 250 B.C.). It is distinguished by its interpretation of the Platonic theory of Ideas in accordance with the number theory of the Pythagoreans.

Speusippus seems to have substituted numbers for Ideas, assigning to them all the attributes, including separate existence, which Plato in his earlier dialogues had attributed to the Ideas.{4} Although, according to Theophrastus, Speusippus devoted but little attention to the study of the natural sciences, on one important point of physical doctrine he differed from Plato, maintaining, if we are to believe our Neo-Pythagorean authorities, that the elements are five, not four, and deriving these five, after the manner of Philolaus, from the five regular figures.{5} If, as is probable, Aristotle, in Analytica Posteriora, II, 13, 97 a, 6, is speaking of Speusippus, the latter maintained that in order to know anything we must know everything.

Xenocrates continued to combine, as Speusippus had done, the number theory of the Pythagoreans with Plato's doctrine of Ideas. He went farther, however, than Speusippus in his application of number to theological notions, developing a system of demonology which suggests in its elaborateness the doctrines of the Neo-Platonists.

Heraclides of Pontus is remarkable for having taught the diurnal revolution of the earth on its axis, and the immobility of the fixed stars. These views were first proposed by Hicetas of Sicily and by Ecphantus, who was also a Sicilian. Our authorities are Theophrastus{6} and Plutarch.{7}

Philip of Opus is generally believed to be the author of Epinomis and the editor of the Laws, of which the Epinomis is a continuation.

Crates and Crantor devoted themselves

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