[91] Plato, Theætêt. p. 165 D. The reasonings here given by Plato from the mouth of Sokrates, are compared by Steinhart to the Trug-schlüsse, which in the Euthydêmus he ascribes to that Sophist and Dionysodorus. But Steinhart says that Plato is here reasoning in the style of Protagoras: an assertion thoroughly gratuitous, for which there is no evidence at all (Steinhart, Einleitung zum Theætêt. p. 53).
[92] Plato, Theætêt. pp. 179-183. The description which we read here (put into the mouth of the geometer Theodôrus) of the persons in Ephesus and other parts of Ionia, who speculated in the vein of Herakleitus — is full of vivid fancy and smartness, but is for that reason the less to be trusted as accurate.
The characteristic features ascribed to these Herakleiteans are quite unlike to the features of Protagoras, so far as we know them; though Protagoras, nevertheless, throughout this dialogue, is spoken of as if he were an Herakleitean. These men are here depicted as half mad — incapable of continuous attention — hating all systematic speech and debate — answering, when addressed, only in brief, symbolical, enigmatic phrases, of which they had a quiver-full, but which they never condescended to explain (ὥσπερ ἐκ φαρέτρας ῥηματίσκια αἰνιγματώδη ἀνασπῶντες ἀποτοξεύουσιν, see Lassalle, vol. i. pp. 32-39 — springing up by spontaneous inspiration, despising instruction, p. 180 A), and each looking down upon the others as ignorant. If we compare the picture thus given by Plato of the Herakleiteans, with the picture which he gives of Protagoras in the dialogue so called, we shall see that the two are as unlike as possible.
Lassalle, in his elaborate work on the philosophy of Herakleitus, attempts to establish the philosophical affinity between Herakleitus and Protagoras: but in my judgment unsuccessfully. According to Lassalle’s own representation of the doctrine of Herakleitus, it is altogether opposed to the most eminent Protagorean doctrine, Ἄνθρωπος ἑαυτῷ μέτρον — and equally opposed to that which Plato seems to imply as Protagorean — Αἴσθησις = Ἐπιστήμη. The elucidation given by Lassalle of Herakleitus, through the analogy of Hegel, is certainly curious and instructive. The Absolute Process of Herakleitus is at variance with Protagoras, not less than the Absolute Object or Substratum of the Eleates, or the Absolute Ideas of Plato. Lassalle admits that Herakleitus is the entire antithesis to Protagoras, yet still contends that he is the prior stage of transition towards Protagoras (vol. i. p. 64).
Sokrates maintains that we do not see with our eyes, but that the mind sees through the eyes: that the mind often conceives and judges by itself without the aid of any bodily organ.
Sokr. — If you are asked, With what does a man perceive white and black? you will answer, with his eyes: shrill or grave sounds? with his ears. Does it not seem to you more correct to say, that we see through our eyes rather than with our eyes:— that we hear through our ears, not with our ears. Theætêt. — I think it is more correct. Sokr. — It would be strange if there were in each man many separate reservoirs, each for a distinct class of perceptions.[93] All perceptions must surely converge towards one common form or centre, call it soul or by any other name, which perceives through them, as organs or instruments, all perceptible objects. —
[93] Plato, Theætêt. p. 184 D. δεινὸν γάρ που, εἰ πολλαί τινες ἐν ἡμῖν, ὥσπερ ἐν δουρείοις ἵπποις, αἰσθήσις ἐγκαθηνται, ἀλλὰ μὴ εἰς μίαν τινὰ ἰδέαν, εἴτε ψυχὴν εἴτε ὅ, τι δεῖ καλεῖν, πάντα ταῦτα ξυντείνει, ᾗ διὰ τούτων οἷον ὀργάνων αἰσθανόμεθα ὅσα αἰσθητά.
We thus perceive objects of sense, according to Plato’s language, with the central form or soul, and through various organs of the body. The various Percepta or Percipienda of tact, vision, hearing — sweet, hot, hard, light — have each its special bodily organ. But no one of these can be perceived through the organ affected to any other. Whatever therefore we conceive or judge respecting any two of them, is not performed through the organ special to either. If we conceive any thing common both to sound and colour, we cannot conceive it either through the auditory or through the visual organ.[94]
[94] Plato, Theætêt. p. 184-185.
Now there are certain judgments (Sokrates argues) which we make common to both, and not exclusively belonging to either. First, we judge that they are two: that each is one, different from the other, and the same with itself: that each is something, or has existence, and that one is not the other. Here are predicates — existence, non-existence, likeness, unlikeness, unity, plurality, sameness, difference, &c., which we affirm, or deny, not respecting either of these sensations exclusively, but respecting all of them. Through what bodily organ do we derive these judgments respecting what is common to all? There is no special organ: the mind perceives, through itself these common properties.[95]