Aristotle assumes the question in favour of θέσει, in his treatise De Interpretatione, without any reasoning, against the Platonic Kratylus; but his commentators, Ammonius and Boethius, note the controversy as one upon which eminent men in antiquity were much divided.
Plato connects his opinion, that names have a natural rectitude of signification, with his general doctrine of self-existent, archetypal, Forms or Ideas. The Stoics, and others who defended the same opinion afterwards, seem to have disconnected it from this latter doctrine.
[3] Plato, Kratyl. pp. 384 C, 391 A.
Argument of Sokrates against Hermogenes — all proceedings of nature are conducted according to fixed laws — speaking and naming among the rest.
Sokrates, refuting Hermogenes, lays down the following doctrines.[4] If propositions are either true or false, names, which are parts of propositions, must be true or false also.[5] Every thing has its own fixed and determinate essence, not relative to us nor varying according to our fancy or pleasure, but existing per se as nature has arranged.[6] All agencies either by one thing upon other things, or by other things upon it, are in like manner determined by nature, independent of our will and choice. If we intend to cut or burn any substance, we must go to work, not according to our own pleasure, but in the manner that nature prescribes: by attempting to do it contrary to nature, we shall do it badly or fail altogether.[7] Now speaking is one of these agencies, and naming is a branch of speaking: what is true of other agencies is true of these also — we must name things, not according to our own will and pleasure, but in the way that nature prescribes that they shall be named.[8] Farther, each agency must be performed by its appropriate instrument: cutting by the axe, boring by the gimlet, weaving by the bodkin. The name is the instrument of naming, whereby we communicate information and distinguish things from each other. It is a didactic instrument: to be employed well, it must be in the hands of a properly qualified person for the purpose of teaching.[9] Not every man, but only the professional craftsman, is competent to fabricate the instruments of cutting and weaving. In like manner, not every man is competent to make a name: no one is competent except the lawgiver or the gifted name-maker, the rarest of all existing artists.[10]
[4] Aristot. De Interpretat. ii. 1-2: Ὄνομα μὲν οὖν ἐστὶ φωνὴ σημαντικὴ κατὰ συνθήκην ἄνευ χρόνου … τὸ δὲ κατὰ συνθήκην, ὅτι φύσει τῶν ὀνομάτων οὐδέν ἐστιν, &c.
This is the same doctrine which Plato puts into the mouth of Hermogenes (Kratylus, p. 384 E), and which Sokrates himself, in the latter half of the dialogue, admits as true to a large extent: that is, he admits that names are significant κατὰ συνθήκην, though he does not deny that they are or may be significant φύσει.
Τὸ ἀπὸ ταὐτομάτου (p. 397 A) is another phrase for expressing the opinion opposed to ὀνομάτων ὀρθότης.
[5] Plato, Kratyl. p. 385.
Here too, Aristotle affirms the contrary: he says (with far more exactness than Plato) that propositions alone are true or false; and that a name taken by itself is neither. (De Interpret. i. 2.)