(b. Athens, ca. 408 b.c.; d. Athens, 339 b.c.)
Speusippus’ father was Eurymedon, and his mother was Plato’s sister Potone. A member of the Academy, he became its head after Plato’s death. He was a friend of Dion and supported his political plans. Diogenes Laërtius lists the titles of thirty writings by Speusippus, but his catalog is incomplete. Only scattered fragments have survived. The thirtieth of the so-called letters of the Socratics is presumably from Speusippus to King Philip of Macedonia, in which the writer boasts that his devotion to the king excels that of Isocrates.
Speusippus distinguished several levels of existence, none of which was assigned to the “ideas.” The highest level is that of the mathematics, specifically that of the numbers. For the interpreter the main problem is the cohesion of these levels. Aristotle charged that there is no more cohesion among them than between the episodes of a bad tragedy. In spite of this criticism, it has been maintained in recent times that the Neoplatonic conception of a gradual “procession” of being from the absolute One can be traced back, if not to Plato himself, at least to the younger members of the Academy, Speusippus and Xenocrates. That Speusippus was one and possibly the first of the thinkers who conceived of an ontological step-by-step descent without any traces of a dualistic idealism was most impressively argued by Merlan, who supported his claim by information on Speusippus’ doctrine, which he had discovered in Iamblichus’ De communi mathematica scientia.
Regarding Aristotle’s criticism of Speusippus as a disjointer, Merlan suggests that it is not aimed at the absence but at the weakness of the vinculum that connects the levels. Not only must any temporal connotation be kept away from this “procession,” but the bond that holds together the parts amounts to no more than an analogy (Merlan, p. 118).
Speusippus recognizes two principles of being, which are of unequal rank. The absolutely first principle is the One, which transcends existence like the One of Plotinus, from which it differs, however, in that it is not identical with the Good. Its inferior counterpart is called the Multitude. On each level of existence being is generated by principles that are analogous to the absolute One and its counterpart. In arithmetic, for example, the first principle is the One, in geometry it is the point.
A large proportion of Speusippus fragments comes from his work ʽOµoια (“Similar Things”) and deals with zoological classifications. They contain a wealth of detailed information, which has been shown to be very similar to accounts of genera and species of animals in Aristotle’s Historia animalium (Lang. pp. 9–15). The principle of Speusippus’ classifications is a modified form of the Platonic diaeresis. The importance of such classifications can be inferred from Speusippus’ assumption that every being is fully determined by the totality of its logical relations to all other beings. This seems to correspond to the doctrine that the concatenation of the levels of existence is constituted by logical relations (analogies).
I. Original Works. A collection of fragments is in Paulus Lang. De Speusippi Academic scriptis. Accedunt fragmenta (Bonn, 1911; repr., Frankfurt, 1964). A new fragment was discovered by R. Klibansky; see Parmenides... nec non Procli Commentarium in Parmenidem interprete Guillelmo de Moerbeka, R. Klibansky and C. Labowsky, eds. (London 1953), 38. For the letter to King Philip of Macedonia, see E. Bickermann and J. Sykutris, “Speusipps Brief an König Philipp...,” in Berichte. Sächsische Akademie der Wissenschaften.80 , fasc, 3 (Leipzig, 1928).
II . Secondary Literature. See also the following, listed chronologically: J. Ravaisson, Speusippi de primis rerum principüs placita (Paris, 1838); Ernst Hambruch, Logische Regeln der platonischen Schule in der aristotelischen Topik (Berlin, 1904); E. Zeller, Die Philosophie der Griechen, 5th ed., II. pt. 1 (1922), 986, n. 3, and 996–1010; E. Frank, Plato und die sogenannten Pythagoreer(Halle, 1923), 239–261; J. Stenzel, “Speusippos,” in Pauly-Wissowa, Real-Encyclopädie der classischen Altertumswissenschaft, 2nd ser., III (1929). 1636–1669; H. Cherniss, Aristotle’s Criticism of Plato and the Academy (Baltimore, 1944), and The Riddle of the Early Academy(Berkeley, 1945; repr., New York, 1962), 31–43 and passim: H. J. Krämer, Der Ursprung der Geistesmetaphysik (Amsterdam, 1964). 207–223; and P. Merlan, in The Cambridge History of Later Greek and Early Medieval Philosophy (Cambridge, 1967), 30–32, and esp. From Platonism to Neoplatonism. 3rd rev. ed. (The Hague, 1968).
Ernst M. Manasse
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Speusippus (spyōōsĬp´əs), fl. 347–339 BC, Greek philosopher; disciple and nephew of Plato, whom he succeeded as head of the Academy. Speusippus distinguished 10 grades of being, thereby prefiguring Neoplatonism. He held that the good is not the source of being but is its goal. One of his most significant ideas is that it is impossible to have satisfactory knowledge of anything without knowing all things besides. A portion of his writings on Pythagorean numbers has survived.
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