¹ For the life and writings of Protagoras see Zeller, E., Die Philosophie der Griechen, 1, 26 (Leipzig, 1920), pp. 1296–1304Google Scholar and notes. For bibliography cf. Überweg-Prächter, Die Philosophie des Altertums (= Überweg, Grundriss der Geschichte der Philosophie, 112 [Berlin, 1926]), pp. 52°–53°, and Nestle, W. in the edition of the Protagoras (Platon, Ausgew. Schriften, IV; Protagoras 7, Leipzig und Berlin, 1921), pp. 65–8Google Scholar (Ibid., pp. 14–32, speak also of the works of the sophist).

² Met., B, 2, 9976, 32–998a, 4. In Kranz, H. Diels-w., Die Fragmente der Vorsokratiker 5 (Berlin, 1935. Quoted as Diels-Kranz),Google Scholar 80 (= H. Diels, Die Fragmente4 [Berlin, 1922. Quoted as Diels], 74), B, 7. This text shows that Protagoras had criticized geometricians, maintaining that the tangent does not touch the circumference at one point only.

³ Nestle, W., in the introduction to his edition of the Protagoras, p. 30Google Scholar, sees in the criticism of geometry a rejection of the objectivity of mathematics. This can be applied to theoretical disciplines in general.

¹ See ερραης in the Hippocratean collection.

² In my interpretation of the thought of Protagoras I deliberately ignore, the work of H. Langerbeck,. εις ηιραμη ("Neue Philologische Untersuchungen.” 10. H. Berlin, 1935, pp. 14–33), which to arbitrariness in reconstruction joins an incomprehension of the philosophical problem in question not easily to be matched.

³ Diels-Kranz, 80 (= Diels, 74), B, 1. Sextus Empiricus, Pyrr. Hypot. 1. 210 (Diels-Kranz and Diels, A, 14), offers an almost identical text. Other texts, in general less complete: Plato, Cratylus, 385e (Ibid., A, 13): Theactus, 160d, 166d (Ibid.. A, 21a), 161c (ibid., B, 1); Aristotle, Met, I, 1, 1053a. 35–36 [wanting in Diels-Kranz and Diels]; K, 6, 1062b, 12–15 (ibid., A, 10); Diogenes laertius, IX, 51 (Ibid., A, 1), identical with Adv. Math., VII, 60]. Hermias, Irr. gent. philos., 9 (Ibid.. A, 16). According to Plato, Theactctus, 166d (Ibid.. A, 210), the proposition was at the beginning of ?λοεια; according to Sextus, K., Adv. Math. (loc. cit.), at the beginning of ?ααρλλοντς; (that is, λγοι). It is generally admitted that it is one and the same work; some think that the former title indicated the first part or λγος; of a work designated by the latter title.

⁴ Plato, Cratylus, 385e; Sextus, P., Pyrr. Hypot., I, 216 [This text is mentioned by H. Gomperz, Sophistik und Rhctorik, Leipzig und Berlin, 1912, p. 202]; Hermias, Irr. gent, phil., 9 (Diels-Kranz and Diels, loc. cit.).

¹ Plato, Theaetetus (Diels-Kranz and Diels, Ibid., B, I).

² H. Gomperz (op. cit., p. 203), although he fitly mentions the text of Sextus Empiricus that explains zpήματα with πρáγματα, and although he translates the former with Tatsachen oder Sachoerhalte, attaches to it subsequently too wide a meaning because he renders it with Alles (all), and affirms that the existence of which Protagoras spoke was being or existing in general (Sein oder existieren schlcchthin [p. 201]). Indeed, all includes not only facts, but also concrete things, qualities, etc.

³ Zeller, E., Die Philosophie der Griechen, I, 2⁶, p. 1355¹Google Scholar. affirms that Protagoras did not distinguish the two meanings of ὡς, though he discarded neither of them. According to Covotti, A., Per la thoria della sofistica greca Studi sulla filosofia teoretica di Protagora (“Annali della R. Scuola Normale Superiore di Pisa,” Filosofia e Filologia, V, xii [xix in the series], Pisa, 1897, p. 70)Google Scholar, “Plato takes ὡς to mean that and applies it sometimes to the truth and falsity of judgments, sometimes to the existence of things in which also their properties are included], and, finally to the existence of things thus determined, and so of the things themselves.”

⁴ Thus Plato uses expressions of this kind to explain the principle of Protagoras, Theactetus, 152, a: ὡς ola μὲν ἔκαστα ὲμοὶψαὶνετυι τοιυũτα μéν ιοτιν éμοí Cratylus, 386a: ὡς ãρα ola μὲν ?μο? øα?νεται τ? πρ?γματα ειναι τοια?τα μ?ν ?στιν ?μο?. … (Diels-Kranz and Diels, Ibid., B, 1; A, 13).

⁵ Pyrr. Hyp., I, 216 (ibid. A, 14).

⁶ Op. cit., p. 204.

⁷ Adv. Math., VII, 60, and Pyrr. Hyp., I, 216 (Diels-Kranz and Diels, ibid., B, I, and A, 14).

⁸ Griechisch Denker, 1⁴, Berlin-Leipzig, 1922, pp. 377ff.Google Scholar

¹ Plato, Theaetetus. 152a, 161c (Diels-Kranz and Diels, Ibid., B, 1), 166d (Ibid.. A, 21a); Cratylits, 386a (A, 13). The Theaetetus, rejecting the thesis of Protagoras, Plato uses with fuller development an argument employed also by Democritus and called περιτροπ? by Sextus Empiricus, Adv. Math., VII, 389 (Diels-Kranz and Diels, Ibid., A, 15), if every opinion is true, true is also the opinion holding that not every opinion is true, so that the opinion that every opinion is true becomes false just for him who maintains it. As H. Gomperz (op. cit., pp. 229–231) has remarked, this criticism implied that Democritus and Plato interpreted ?νθρωπος in an individual sense. The same interpretation is given by Aristotle (Met., ?, 4, 1007b, 18–25 [Diels-Kranz and Diels), Ibid., A, 19]; 5, 1009a, 5–15; K, 6, 1062b, 13–19 [Diels-Kranz, Ibid.], and by Sextus Empiricus (Pyrr. Hyp., I, 216) [Ibid., A, 14]; Adv. Math., Vll, 60 [Ibid., B, 1]. H. Gomperz, who has studied the question with a particular care, says that the ancient testimonies justifying the individual interpretation of man are much more numerous than the others; but then, there are some (Aristotle, Met., θ, 3, 1046b, 29–1047a, 8 [Ibid.. A, 17]; Sextus Empiricus, Pyrr. Hyp., I, 219 [Ibid., A, 14]; Hermias, Irr., 9 [Ibid., 16]) showing that Protagoras himself understood his principle in a general sense, which, however, is not in contradiction with the individual, but rather presupposes it. This interpretation, which Gomperz calls distributive, affirms that “existence in general belongs to what is felt or thought even by one man, whereas it does not belong to what is not even once felt or thought by any one man” (op. cit., pp. 223–31, Quot. p. 222).These statements are correct, but they do not go to the core of the matter because not only does the distributive interpretation presuppose the individual interpretation, but it is a consequence of it, so that the contrast remains between the individual interpretation and the general interpretation proper, which relates existence to any man, inasmuch as he is endowed with a nature common to all men. Finally, we may recollect that W. Nestle has observed that the principle of Protagoras might be interpreted also in a communal sense, taking man to mean group (people, race, state). In his opinion, however, Protagoras is not likely to have made these distinctions, but it cannot be doubted that, with some limitations, his gnoseology was individualistic. (Introduction to the Protagoras, p. 14; in Zeller, p. 135910).

¹ The evidence of Diogenes Laertius, IX, 51 (Diels-Kranz and Diels, ibid. A, 1): “[Pr.] said that the soul is nothing but sensations, as also Plato says in the Theaetetus” is clearly derived from this dialogue. No greater importance is to be attached to the statements of Hermias, Irr., 9, and Eusebius, Praep. Evang., XIV, 19, 8 (Ibid., A, 16).

² According to custom this word is translated with “sensation"; but “sensible perception” would be a better rendering.

³ Gomperz, H., op. cit., pp. 205–6Google Scholar, has used this argument. It can be doubted whether Protagoras actually applied his principle to ethical conceptions for which Plato uses the expression δο?ε?ν (Theaetetus, i67c; Diels-Kranz and Diels, Ibid. A, 21a). But even admitting this, one must not forget that the same dialogue uses δο?ο?ν (161c, Ibid., B, 1) after giving instances of sensible perceptions.

¹ Met., Γ, 5, 1009a, 7.

² Ibid., 4, 1007b, 23 (Diels-Kranz and Diels, Ibid.. A, 19). This text and the other given above are mentioned by Gomperz, H., op. cit., p. 206.Google Scholar

³ Met., I, 1, 1053a, 356, 1.

⁴ 171a–c. See p. 91. It can be also said with Covotti (op. cit., pp. 44 ff.) that at 164d Socrates distinguishes the thesis of Protagoras from the identification of αïσθησις and ?πιστ?μη.

¹ Iliad, XIV, 201.Google ScholarThe Cratylvs (702a–c) mentions Heraclitus, Homer (of whom the same line is quoted), Hesiod, and Orpheus as supporters of the universal motion of things.

² In the interpretation of 153e–154a and especially in explaining τòπροβáλλον and τò προσβαλλóμενον as active and passive movement I follow Taylor, A. E., Plato3, London, 1929, p. 327.Google Scholar

¹ Also in the interpretation of this passage (1546) I follow Taylor, op. cit., P. 327.

¹ A more precise distinction of the two theories than is usually offered by the interpreters is that made by A. Diès in the introduction and division into paragraphs of his edition of Theaetetus (Platon, Œuvres complètes, t. VIII,

² partie, Paris, “Les Belles Lettres,” 1934, pp. 131–2, 171, 177). In my opinion the texts of the Theaetetus show that we have here different theories, and that we cannot follow F. M. Cornford (Plato's Theory of Knowledge, London, 1935, PP. 48–9) and identify the κομψο? with the philosophers mentioned in 152e, that is, with all the wise men excepting Parmenides. J Friction had already been mentioned in the account of the first theory (153a).

³ In the general discussion of the theory of the universality of movement, the latter is said to be either motion from place to place or alteration (?λλο?ωοις) (181d).

⁴ Op. cit., p. 329.

⁵ Diels-Kranz, 80 (= Diels, 79), A, 19.

¹ Aristotle's silence on this subject is significant.

¹ Diels—Kranz, 59 (= Diels, 46), B, 6.

² Ibid., B, 12.

³ Ibid., B, 6.

⁴ Sophistik und Rhetorik, pp. 252—253.

⁵ Aristotle, Phys., A, 4, 1876, 2.

⁶ Sophistik und Rhetorik, pp. 233—7, 251—3, 259—70.

¹ See pp. 28–9.

² An interpretation similar to that of H. Gomperz is the one recently offered by F. M. Cornford (Plato's Theory of Knowledge). In his opinion, Protagoras thinks that the same thing possesses contrary qualities, e.g. (152b) that the same wind is hot and cold at the same time. This thesis, not contrasting with the naive realism of common sense for which objects have actually the qualities perceived in them, agrees with the teaching of Anaxagoras and the doctrine of Heraclitus about the inseparable existence of opposites. If we admit this, we cannot think that Protagoras was a subjectivist; even the word relativist applied to him is a misnomer and a cause of error, because for him heat and cold together with all the other properties that we can perceive in the wind do exist independently of any percipient, and constitute wind in itself. The other interpretation of the example of the wind, in force of which cold and heat do not exist in it until it encounters a percipient, is a Platonic construction on the basis of the ambiguous statement of the sophist (op. cit., pp. 33–6). Many of the objections raised against Gomperz do not apply to Cornford, because he does not attribute to Protagoras the Heraclitism said to have been taught in secret to his disciples. However, his interpretation is quite controvertible. Ancient sources do not refer to intercourse between Protagoras and Anaxagoras, and Plato who, for theoretical purposes, had to connect the teaching of the sophist with that of Heraclitus, might have

¹ An interpretation similar to that of H. Gomperz is the one recently offered by F. M. Cornford (Plato's Theory of Knowledge). In his opinion, Protagoras thinks that the same thing possesses contrary qualities, e.g. (1526) that the same wind is hot and cold at the same time. This thesis, not contrasting with the naive realism of common sense for which objects have actually the qualities perceived in them, agrees with the teaching of Anaxagoras and the doctrine of Heraclitus about the inseparable existence of opposites. If we admit this, we cannot think that Protagoras was a subjectivist; even the word relativist applied to him is a misnomer and a cause of error, because for him heat and cold together with all the other properties that we can perceive in the wind do exist independently of any percipient, and constitute wind in itself. The other interpretation of the example of the wind, in force of which cold and heat do not exist in it until it encounters a percipient, is a Platonic construction on the basis of the ambiguous statement of the sophist (op. cit., pp. 33–6). Many of the objections raised against Gomperz do not apply to Cornford, because he does not attribute to Protagoras the Heraclitism said to have been taught in secret to his disciples. However, his interpretation is quite controvertible. Ancient sources do not refer to intercourse between Protagoras and Anaxagoras, and Plato who, for theoretical purposes, had to connect the teaching of the sophist with that of Heraclitus, might have mentioned Anaxagoras in the Cratylos. A stronger argument against Cornford is offered by the fact that the thesis attributed by him to Protagoras and justified in the Theaetetus with Heraclitism in its two forms, finds no justification without such doctrines. In the silence of ancient sources to the purpose, we cannot attribute to the sophist the explanation offered by Anaxagoras, that we apprehend qualities through their contraries, which all exist in us; so we perceive hot through cold and vice versa (Theophrastus, De sensu, 28; Diels—Kranz, 59 [= Diels, 46], A, 92).

¹ In 1790-d, after subjecting the proposition of Protagoras to different criticisms, Socrates says that it is necessary to sift the matter more accurately, studying the value of the thesis of universal movement. Taylor is, therefore, right in saying that the theory of the κομψο? (we can rather say of Heraclitism in general, as it is.presented by the Theaetetus) is an ontology professing to supply the foundations for the individualistic gnoseology of the sophist (op. cit., p. 329).

¹ Protagoras, Antisthenes, Aristippus (and the school of Cyrene) are the names suggested by those who attribute to a definite thinker the fusion of sensism, relativism, and the Heraclitean doctrine of universal motion. See Diels, op. cit., p. 1501.

² I think that, altogether, Diès is in the right when he says that to append a particular signature to so constructive a theory is to restrict it unduly (Introduction to the Theaetetus, op. cit., p. 150).

¹ Diels-Kranz and Diels, Ibid., A, 21a.

² Aristotle, Met., K, 6, 1062b, 13–19 (Diels-Kranz, Ibid., A, 19), saying that from the principle of Protagoras it can be inferred that the same thing is good and bad, implies that the sophist had not applied this proposition to moral life.

³ According to Covotti (op. cit., pp. 48–52) it can be inferred that the utilitaristic theory cannot be attributed to Protagoras from the following passages: “If he, being himself present, granted these things, and if it were not we that allowed them coining to his rescue, it would not be necessary to return to them and stress them; but now someone might find that we have not been warranted to agree to this on his behalf” (169e); “If suddenly he [Protagoras] rose up to his neck, and reproached me for speaking a lot of nonsense. and you for concurring.” (171d).

⁴ Op. cit., p. 333.

¹ A confirmation of this suggestion can be found in the language used by Protagoras in the myth and the logos; in fact, he uses the expression τ?ληθ? λ?γειν only when he says that it is not admissible that one who is not a madman should not say that he possesses justice and the other virtues (Prot., 323b). The words “true” and “false” are not used for ethical judgments.

² See p. 1.

¹ Diels-Kranz and Diels, Ibid., A, 19. According to this text, such a proposition had been used by persons living in older times than Protagoras. Diels and others think of Heraclitus, but, as Taylor thinks (op. dt., p. 961), it must be Parmenides who had maintained that one cannot speak of what does not exist; contradiction indeed requires that one at least of the contrary judgments should say what is not. Instead, Aristotle from the Protagorean man-measure thesis, infers that contradictory propositions can be stated about everything; nay, that all things are one. As he appears to each, a man will be, and will not be, a trireme; and the same thing will be a man, a wall, and a trireme (Met., ?, 4, 1007b, 18–25). But Protagoras, though admitting the existence of objects external to subjects, thought that ?ρ?ματα or facts (namely, the belonging to them of certain attributes) varied according to the subjects and their conditions, and therefore denied that two persons could speak of the same thing.

² This is the translation of the text as reconstructed by Diels (Diels-Kranz and Diels, Ibid., B, 4) friom Eusebius (Praep. Evang)., XIV, 3, 7, and Diogenes Laertius, IX, 51. The former has OVK olda, the latter OVK i%w eldivai. Only in Eusebius we find the words ov"0 ovolol Tiveg ideav, which are wanting in Diogenes; in Hesychius, Onomatol. in Schol. Plat, de Rep., 600c (Diels-Kranz and Diels, Ibid., A, 3), and in Plato, Theaetetus, i6zd (Ibid., 23), but are given by Sextus Empiricus, Aedv. Math., IX, 55–6 (who quotes also verses from Timon (Ibid., A, 12), by Cicero, De Nat. Deorum), I, 12, 29 (Ibid., A, 23), and by Philodemus, De pietate, c. 22, p. 89s (Ibid.), which means that they were in an Epicurean source common to the last two. The last part of the text ("because many things …") is wanting in Eusebius. Other evidence: Philostratus, Vit. Sophist., I, 10, 2 (ibid., A, 2); Cicero, De Nat. Deorum, I, 24, 63 (Ibid., A, 23). According to ancient evidence, Protagoras, accused of impiety in Athens for the beginning of his work on the Gods, fled from justice and, while going to Sicily, was shipwrecked and died. His books were publicly burnt (Diels-Kranz and Diels, Ibid., A, 1, 2, 3, 4, 12, 23).

¹ Phil, der Griechen, I, 26, p. 1406Google Scholar.

² Introduction to the Protagoras, p. 18.

³ Sophistik und Rhetorik, pp. 131 and 189.

⁴ See Überweg-Prächter, op. cit., p. 129. Without reason Nestle (op. cit., p. 32) puts him among the disciples of Protagoras; quite reasonably instead it has been remarked that we cannot consider as a sophist one who, for aught we know, did not justify rationally his negation.