Note 79 — Chapter XXVIII · THEÆTETUS.
Reading edition
Plutarch, adv. Kolot. p. 1108.
According to Demokritus all sensible perceptions were conventional, or varied according to circumstances, or according to the diversity of the percipient Subject; but there was an objective reality — minute, solid, invisible atoms, differing in figure, position, and movement, and vacuum along with them. Such reality was intelligible only by Reason. Νόμῳ γλυκύ, νόμῳ πικρόν, νόμῳ θερμόν, νόμῳ ψυχρόν, νόμῳ χροιή· ἐτέῃ δὲ ἄτομα καὶ κενόν. Ἅπερ νομίζεται μὲν εἶναι καὶ δοξάζεται τὰ αἰσθητά, οὐκ ἔστι δὲ κατὰ ἀληθείαν ταῦτα· ἀλλὰ τὰ ἄτομα μόνον καὶ κένον.
Sextus Empiric. adv. Mathemat. vii. 135-139; Diog. Laert. ix. 72. See Mullach, Democriti Fragm. pp. 204-208.
The discourse of Protagoras Περὶ τοῦ ὄντος, was read by Porphyry, who apparently cited from it a passage verbatim, which citation Eusebius unfortunately has not preserved (Eusebius, Præpar. Evang. x. 3, 17). One of the speakers in Porphyry’s dialogue (describing a repast at the house of Longinus at Athens to celebrate Plato’s birthday) accused Plato of having copied largely from the arguments of Protagoras — πρὸς τοὺς ἓν τὸ ὂν εἰσάγοντας. Allusion is probably made to the Platonic dialogues Parmenides and Sophistes.