[31] See the treatise of Aristotle or Pseudo-Aristotle, De Melisso, Xenophane, et Gorgiâ, in Aristot. p. 979-980, Bekker, also in Mullach’s edition, p. 62-78. The argument of Gorgias is also abridged by Sextus Empiric. adv. Mathemat. vii. p. 384, sect. 65-86.
See also a copious commentary on the Aristotelian treatise in Foss, De Gorgiâ Leontino, p. 115 seq.
The text of the Aristotelian treatise is so corrupt as to be often unintelligible.
As to the first point, Ens was no more real or existent than Non-Ens: the word Non-Ens must have an objective meaning, as well as the word Ens: it was Non-Ens, therefore it was, or existed. Both of them existed alike, or rather neither of them existed. Moreover, if Ens existed, it must exist either as One or as Many — either as eternal or as generated — either in itself, or in some other place. But Melissus, Zeno, and other previous philosophers, had shown sufficient cause against each of these alternatives separately taken. Each of the alternative essential predicates had been separately disproved; therefore the subject, Ens, could not exist under either of them, or could not exist at all.
Ens, incogitable and unknowable.
As to the second point, let us grant that Ens or Entia exist; they would nevertheless (argued Gorgias) be incogitable and unknowable. To be cogitated is no more an attribute of Ens than of Non-Ens. The fact of cogitation does not require Ens as a condition, or attest Ens as an absolute or thing in itself. If our cogitation required or attained Ens as an indispensable object, then there could be no fictitious cogitata nor any false propositions. We think of a man flying in the air, or of a chariot race on the surface of the sea. If our cogitata were realities, these must be so as well as the rest: if realities alone were the object of cogitation, then these could not be thought of. As Non-Ens was thus undeniably the object of cogitation, so Ens could not be its object: for what was true respecting one of these contraries, could not be true respecting the other.
Ens, even if granted to be knowable, is still incommunicable to others.
As to the third point: Assuming Ens both to exist and to be known by you, you cannot (said Gorgias) declare or explain it to any one else. You profess to have learnt what Ens is in itself, by your sight or other perceptions but you declare to others by means of words, and these words are neither themselves the absolute Ens, nor do they bring Ens before the hearer. Even though you yourself know Ens, you cannot, by your words, enable him to know it. If he is to know Ens, he must know it in the same way as you. Moreover, neither your words, nor Ens itself, will convey to the hearer the same knowledge as to you; for the same cannot be at once in two distinct subjects; and even if it were, yet since you and the hearer are not completely alike, so the effect of the same object on both of you will not appear to be like.[32]
[32] In this third branch of the argument, showing that Ens, even if known, cannot be communicable to others, Gorgias travels beyond the Absolute, and directs his reasoning against the communicability of the Relative or Phenomenal also. Both of his arguments against such communicability have some foundation, and serve to prove that the communicability cannot be exact or entire, even in the case of sensible facts. The sensations thoughts, emotions, &c., of one person are not exactly like those of another.