Protagoreanism is initially introduced as the thesis that we are, each of us, the measure of how things are for us: what appearsa certain way to a given subject is that way for that subject. In the interests of assimilating this to Theaetetus' definition of knowledge asperception, it isquickly repackaged by Socratesasthe thesisthat what appearsperceptually in a certain way to each subject is that way for that subject. He achieves this limitation by deciding that the verb ‘appear’ is being used in its specifically perceptual sense
72 I argue thisin Sedley (2003b, ch. 5).
(152b12–13). Yet in much of the critique that will follow it seems to regain its broader sense, spanning all judgement and not just narrowly perceptual ‘appearance’. We can follow Gail Fine73 in calling the two positions that result ‘broad Protagoreanism’ and ‘narrow Protagoreanism’: the former makes all appearances authoritative, the latter only sensory appearances. Is this alternation between a narrow and a broad version of Protagoreanism a piece of licence on Socrates' part, or a reflection of Protagoras' actual position?
Unfortunately we know next to nothing about what the historical fifth-century sophist Protagoras intended by his Measure Doctrine. We can be pretty confident that itsreported formulation—‘Man isthe measure of all things…’—is authentic, and that it occurred in hisbook entitled Truth. But regarding itsinterpretation, virtually the entire ancient tradition wasdependent on Plato'sconstrual of it in the Theaetetus, and istherefore disqualified asindependent evidence. Asa result it ishard to know how, if at all, Socratesisusing the actual Protagorean thesisfor hisown ends, how far simply inventing it. It could, for example, be that Protagoras' initial motivation was political, and, if so, that he wasmore interested in the authority of human groups, including whole cities(cf. Tht. 168b6), than in that of isolated individuals.74
The Protagoraswho appearsin Plato'searly dialogue Protagoras doesnot reveal hishand asany kind of relativist,75 although nothing that he says there positively excludes his being one. Perhaps the most one should venture to say on the basis of Plato's own evidence outside the Theaetetus isthe following. In the Cratylus, widely
73 Fine (1996). I prefer to skirt round the issue raised by Fine (1995, 1996, 1998) of the appositeness of attributing ‘relativism’ to Protagoras (she herself prefers ‘infallibilism’).
Briefly, I incline to the view that, on any reading, relativity istoo heavily emphasized in the Theaetetus account of Protagoras(e.g. 157a6, 160b8–10) to make it prudent to abandon the term, and that we can usefully instead follow Silverman (2000: 123), who classifiesFine'sposition asa ‘relativism of worlds’, as distinct from a relativism of truthsor one of agentsor appearances.
74 For meticulous discussion of this and other aspects, see Farrar (1988).
75 To be able to point out that thisor that property belongsto thingsonly in some relation, asProtagorasdoesfor beneficial or good at Prot. 334a3–c6, isnot itself an example of relativism, as some commentators have incautiously inferred, although it might perhaps be used in another context to help ground an argument for relativism, similarly to the ‘dice’ passage at Tht. 154b6–155d5.
agreed to pre-date the Theaetetus,76 he already presents Protagoras as a relativist of the ‘broad’ persuasion (385e4–386d2).77Since in the Cratylus Socratesdoesnot have the same motive that he doesin the Theaetetus to invent an unhistorical Protagoras (he is not interested there in discussing perception, for example), this provides some independent reason for thinking that Protagoras was, so far as the existing historical tradition was concerned, a broad rather than a narrowly perceptual relativist.
There is, in fact, one item of independent evidence, rarely noticed in this context,78which strongly supports a historical claim along the above lines. We have a report of a conversation between Protagoras and Zeno of Elea, said to have run asfollows:
‘Tell me, Protagoras,’ said Zeno, ‘if one grain of millet falls, does it make a noise? And what about one ten-thousandth of a grain?’ When Protagorassaid that they do not, Zeno went on: ‘What if a bushel of millet falls?
Does it make a noise, or not?’ ‘It does,’ replied Protagoras. ‘Well now,’ said Zeno, ‘does the bushel of millet stand in a ratio to the single grain, and to its ten-thousandth part?’ Protagorasagreed. ‘Well,’ said Zeno, ‘won't the noises they make also stand in those same ratios to each other? For as are the things making the noises, so are the noises.
In which case, if the bushel makes a noise, the single grain and its ten-thousandth part will also make a noise.’ That ishow Zeno put the argument.
The full report comesfrom Simplicius' commentary on Aristotle'sPhysics (1108.18–28), but the basis of the anecdote wasalready in Aristotle'stext (Physics 250a19–21). Although the context in Aristotle is a physical one concerning change, it seems to me a highly plausible conjecture, to say the least, that the original context of the discussion was one in which Zeno wasengaged in generating a contradiction in Protagoras' position. The device of getting Protagorasto admit the existence of noises below the threshold of
76 In Sedley (2003b ) I defend a modified version of this. The Cratylus belongswith the main body of Plato'smiddle-period dialogues, i.e. before the Theaetetus, asthe stylometric data indicate, but shows signs of late re-editing. This, if true, could appear to weaken its reliability as evidence for Plato's pre-Theaetetus take on Protagoras. But it seems likely that the passage of the Cratylus criticizing Protagorasdoespre-date the Theaetetus, because it relies solely on the argument from differing degrees of wisdom, which in the Theaetetus Socrates will admit can prima facie be answered by Protagoras (see next note and Ch. 3 §1).
77 The criticism there, that Protagoreanism eliminates differing degrees of wisdom, corresponds closely to Tht. 161c2–162a3, aimed primarily at broad Protagoreanism.
78 I made the following suggestion briefly in Sedley (1977: 112 n. 85); it isdeveloped by Wardy (1990: 319–23).
perception can be read asexploiting the same ambiguity of ‘appear’ asI noted above. Protagoras, who equated truth with what appears to each person, had not appreciated that the very same thing might appear in opposite ways to the same person at the same time: it both does (judgementally) and does not (perceptually) appear to Protagoras that a tiny fragment of an ear of corn makes a noise when dropped. Whether the anecdote derived from historical reportage about Zeno,79or from a fictional literary dialogue of unknown authorship, it is valuable testimony to a contemporary or near-contemporary interpretation of Protagorasthat isindependent of Plato. Protagoraswas, on thisevidence, interpreted asa broad epistemological relativist, for whom the ‘appearances’ that he proclaimed to be authoritative ranged over both sensory impressions and reflective judgements, apparently without discrimination.
In the light of this, a promising way to interpret Socrates' strategy in the Theaetetus will be asfollows. Rather than repeat, ashe might have done, the Zenonian criticism of Protagoras, he deliberately leavesintact the ambiguity of
‘appear’ that was already present in Protagoras' thesis. In this way, he can split his critique into two halves (corresponding to broad and narrow Protagoreanism). The first will attack the attribution of sole authority to appearances in the broad sense which includes all beliefs: that is, it will criticize out-and-out relativism. The second will concentrate its attack on the attribution of sole authority to appearances in the narrower, perceptual sense: that is, it will criticize the empiricism implicit in Theaetetus' definition ‘Knowledge isperception’. It isnot that Socratesis himself confused about the distinction; rather, it suits his strategy to let Protagoras go on being inexplicit about it. Or, it might be better to say, it suits Plato to let Socrates leave the ambiguity intact, so that he can display his midwife at work as a critic of two distinct aspects of the existing climate of thought—relativism and empiricism.
What little plausibility Socrates can confer upon the conflation of narrow with broad Protagoreanism is to be found at 156b2–7. The Secret Doctrine characterizes ‘perceptions’ asfollows: ‘they are
79 This availability of a dependable oral tradition about Zeno early enough to be drawn on by Aristotle should not be neglected. Zeno's motion paradoxes (asI plan to argue at greater length elsewhere) must have been preserved for later antiquity solely by Aristotle, since all later reports including Simplicius' depend on Aristotle's, showing that they cannot have been in Zeno's book, to which Simplicius had independent access; they are nevertheless universally agreed to derive from Zeno himself, not from somebody else's literary fiction about him.
called seeings, hearings, smellings, coolings, and heatings, and moreover pleasures, pains, desires, fears, and others, of which countless ones have no name but a huge number do have a name.’ And soon after, at 157d7–9, Socratesand Theaetetusspeak in a way which takesit for granted that ‘good’ and ‘beautiful’ are by now among the predicatesthat the Protagorean theory catersfor. The idea isthat our ‘perceptions’ of the world are not limited to the registering of colours, sounds, etc., but include all the affective and evaluative states that accompany our sensory interaction with the world, and along with these the evaluative predicates that we attach to things. Thus we may infer that if, for example, the assembly decides that going to war is a good idea, this will be the expression of its collective desires or fears, which are themselves its direct and incorrigible registerings of the way the world currently is for the assembly's members. Any such diagnosis involves a highly reductive account of human rationality, and there is no reason to think either that the historical Protagoras held such a view or that Plato seriously attributes it to him. It is, in its present strategic context, no more than a sticking plaster to hide the considerable gap that remains between narrow and broad Protagoreanism.
The fact that Theaetetus' definition of knowledge asperception mergesinto both narrow and broad Protagoreanism makes it hard to supply any label that will adequately capture the underlying thesis to whose refutation part I is devoted. However, I shall permit myself in the remainder of this book to call part I, asI have already been doing, Socrates' refutation of ‘empiricism’. This is because on both the narrow and the broad reading Theaetetus' equation of knowledge with perception is treated as singling out our sensory experience of the world as the sole route to knowledge. On the narrower of the two readings, sensory experience already exhausts our knowledge; on the broader reading, it ismerely the basisof a potentially comprehensive range of cognitionsabout the world and itscontents. But on either version the empiricist canon is observed: there is no kind of knowledge which does not either consist in or depend on sensory experience.80
It is on the critique of broad Protagoreanism that I shall focus in the next chapter.
80 Cf. the characterization of partI by the anonymouscommentator on the Theaetetus, ‘Since…from the fact that the senses have something striking about them those who overvalued them attributed accuracy to them aswell, thisisthe first belief that he will criticize’ (3.7–15).