(Ποτάμων).
1. Of Alexandria. Of this philosopher we have notices in Diogenes Laertius (Prooem. § 21), Porphyrius (de Vita Plotini, in Fabric. Bibl. Graec. vol. ii. p. 109, old ed.), and Suidas (s. vv. αἵρεσις, Ποτάμων). Many attempts have been made to reconcile, by emendation and conjecture, the discrepancies found in these notices, or to ascertain the truth regarding him. Of these an elaborate account will be found in Brucker's Historia Criticae Philosophiae (vol. ii. p. 193, &c.). This subject has also been investigated in a treatise by Gloeckner, entitled, De Potamonis Alex. Philosophia Eclectica, recentiorum Platonicorum Disciplinae admodum dissimili, Disput. 4to. Lipsiae, 1745. Of this an excellent abstract is given by Harless (in Fabric. ibid. vol. iii. p. 184, &c.). What is chiefly interesting and important regarding Potamon, is the fact recorded by Laertius, that, immediately before his time (πρὸ ὀλίγου), Potamon had introduced an eclectic sect of philosophy (ἐκλεκτική τις αἵρεσις). Modern writers have made too much of this solitary fact, for we read nowhere else of this school of Potamon. The meaning of Porphyrius, in the passage referred to above, is by no means clear. It is impossible to tell whether he makes Potanion the occasional disciple of Plotinus, or Plotinus of Potamon. Suidas, in the article αἵρεσις, evidently quotes Laertius, but in Ποτάμων he states, that he lived πρὸ Αὐγούστου, καὶ μετʼ αὐτόν. Whatever meaning these words may have--for that is one of the points of discussion in this question--the two articles are irreconcileable. Indeed, Suidas exhibits his usual confusion in this name. He makes (s. v. Λεσβώναξ) Potamon the rhetorician [No. 2], a philosopher, and we need not encumber the question with his unsupported authority on a point of chronology. Yet, to accommodate his statement with those of Laertius and Porphyrius, Gloeckner and Harless suppose three Potamons. For this, or even for the supposition that there were two, there seems no necessity. Setting aside the authority of Suidas, remembering the uncertainty of the time of Laertius --to determine which his mention of Potamon may furnish a new element,--we cannot but attach much weight to the statement of Porphyrius, the contemporary of Plotinus, and who refers to Potamon, as a well-known name. We should, therefore, conclude that the Potamon mentioned by Laertius and Porphyrius are the same, and, on a minute investigation of the passage where he is mentioned by the latter author, that he was older than Plotinus, and entrusted his children to his guardianship. He may have brought from Alexandria to Rome the idea of an eclectic school. But he had no followers in his peculiar combinations. They were supplanted by the school that endeavoured to ingraft Christianity upon the older systems of philosophy. Indeed, the short notice given by Laertius does not entitle Potamon to the distinction invariably conferred upon him, that ho was the first to introduce an eclectic school; though, probably, he was the first who taught at Rome a system so called.
Laertius states briefly a few of his tenets, derived from his writings, from which we can only learn that he combined the doctrines of Plato with the Stoical and Aristotelian, and not without original views of his own. According to Suidas he wrote a commentary on the Republic of Plato.