Chapter XXVIII: Theætetus (4)

Such is the doctrine which Plato here lays down, respecting the difference between sensible perception, and knowledge or cognition. From his time to the present day, the same topic has continued to be discussed, with different opinions on the part of philosophers. Plato's views are interesting, as far as his language enables us to make them out. He does not agree with those who treat sensation or sensible perception (in his language, the two are not distinguished) as a bodily phenomenon, and intelligence as a mental phenomenon. He regards both as belonging to the mind or soul. He considers that the mind is sentient as well as intelligent: and moreover, that the sentient mind is the essential basis and preliminary--universal among men and animals, as well as coæval with birth--furnishing all the matter, upon which the intelligent mind has to work. He says nothing, in this dialogue, about the three distinct souls or minds (rational, courageous, and appetitive), in one and the same body, which form so capital a feature in his Timæus and Republic: nothing about eternal, self-existent, substantial Ideas, or about the pre-existence of the soul and its reminiscence as the process of acquiring knowledge. Nor does he countenance the doctrine of innate ideas, instinctive beliefs, immediate mental intuitions, internal senses, &c., which have been recognised by many philosophers. Plato supposes the intelligent mind to work altogether upon the facts of sense; to review and compare them with one another; and to compute facts present or past, with a view to the future. All this is quite different from the mental intuitions and instincts, assumed by various modern philosophers as common to all mankind. The operations, which Plato ascribes to the intelligent mind, are said to be out of the reach of the common man, and not to be attainable except by a few, with difficulty and labour. The distinctive feature of the sentient mind, according to him, is, that it operates through a special bodily organ of sense: whereas the intelligent mind has no such special bodily organ.

[Side-note: Different views given by Plato in other dialogues.]

But this distinction, in the first place, is not consistent with Timæus--wherein Plato assigns to each of his three human souls a separate and special region of the bodily organism, as its physical basis. Nor, in the second place, is it consistent with that larger range of observed facts which the farther development of physiology has brought to view. To Plato and Aristotle the nerves and the nervous system were wholly unknown: but it is now ascertained that the optic, auditory, and other nerves of sense, are only branches of a complicated system of sensory and motory nerves, attached to the brain and spinal cord as a centre: each nerve of sense having its own special mode of excitability or manifestation. Now the physical agency whereby sensation is carried on, is, not the organ of sense alone, but the cerebral centre acting along with that organ: whereas in the intellectual and memorial processes, the agency of the cerebral centre and other internal parts of the nervous system are sufficient, without any excitement beginning at the peripheral extremity of the special organ of sense, or even though that organ be disabled. We know the intelligent mind only in an embodied condition: that is, as working along with and through its own physical agency. When Plato, therefore, says that the mind thinks, computes, compares, &c., by itself--this is true only as signifying that it does so without the initiatory stimulus of a special organ of sense; not as signifying that it does so without the central nervous force or currents--an agency essential alike to thought, to sensation, to emotion, and to appetite.

[Side-note: Plato's discussion of this question here exhibits a remarkable advance in analytical psychology. The mind rises from Sensation, first to Opinion, then to Cognition.]

Putting ourselves back to the Platonic period, we must recognise that the discussion of the theory [Greek: Ai)/sthêsis = E)pistê/mê], as it is conducted by Plato, exhibits a remarkable advance in psychological analysis. In analysing the mental phenomena, Plato displayed much more subtlety and acuteness than his predecessors--as far at least as we have the means of appreciating the latter. It is convenient to distinguish intellect from sensation (or sensible perception) and emotion, though both of them are essential and co-ordinate parts of our mental system, and are so recognised by Plato. It is also true that the discrimination of our sensations from each other, comparisons of likeness or unlikeness between them, observation of co-existence or sequence, and apprehension of other relations between them, &c., are more properly classified as belonging to intellect than to sense. But the language of psychology is, and always has been, so indeterminate, that it is difficult to say how much any writer means to include under the terms Sense[99]--Sensation--Sensible Perception--[Greek: Ai)/sthêsis]. The propositions in which our knowledge is embodied, affirm--not sensations detached and isolated, but--various relations of antecedence and consequence, likeness, difference, &c., between two or more sensations or facts of sense. We rise thus to a state of mind more complicated than simple sensation: including (along with sensation), association, memory, discrimination, comparison of sensations, abstraction, and generalisation. This is what Plato calls opinion[100] or belief; a mental process, which, though presupposing sensations and based upon them, he affirms to be carried on by the mind through itself, not through any special bodily organ. In this respect it agrees with what he calls knowledge or cognition. Opinion or belief is the lowest form, possessed in different grades by all men, of this exclusively mental process: knowledge or cognition is the highest form of the same, attained only by a select few. Both opinion, and cognition, consist in comparisons and computations made by the mind about the facts of sense. But cognition (in Plato's view) has special marks:--

1. That it is infallible, while opinion is fallible. You have it[101] or you have it not--but there is no mistake possible.

2. That it apprehends what Plato calls the real essence of things, and real truth, which, on the contrary, Opinion does not apprehend.

3. That the person who possesses it can maintain his own consistency under cross-examination, and can test the consistency of others by cross-examining them ([Greek: lo/gon dou=nai kai\ de/xasthai]).

[Footnote 99: The discussion in pp. 184-186-186 of the Theætêtus is interesting as the earliest attempt remaining to classify psychological phenomena. What Demokritus and others proposed with the same view--the analogy or discrepancy between [Greek: to\ ai)stha/nesthai] and [Greek: to\ noei=n]--we gather only from the brief notices of Aristotle and others. Plato considers himself to have established, that "cognition is not to be sought at all in sensible perception, but in that function, whatever it be, which is predicated of the mind when it busies itself _per se_ (_i.e._ not through any special bodily organ) about existences" (p. 187 A). We may here remark, as to the dispute between Plato and Protagoras, that Plato here does not at all escape from the region of the Relative, or from the Protagorean formula, _Homo Mensura_. He passes from Mind Percipient to Mind Cogitant; but these new Entia cogitationis (as his language implies) are still relative, though relative to the Cogitant and not to the Percipient. He reduces Mind Sentient to the narrowest functions, including only each isolated impression of one or other among the five senses. When we see a clock on the wall and hear it strike twelve--we have a visual impression of black from the hands, of white from the face, and an audible impression from each stroke. But this is all (according to Plato) which we have from sense, or which addresses itself to the sentient mind. All beyond this (according to him) is apprehended by the cogitant mind: all discrimination, comparison, and relation--such as the succession, or one, two, three, &c., of the separate impressions, the likeness of one stroke to the preceding, the contrast or dissimilarity of the black with the white--even the simplest acts of discrimination or comparison belong (in Plato's view) to mental powers beyond and apart from sense; much more, of course, apprehension of the common properties of all, and of those extreme abstractions to which we apply the words Ens and Non-Ens ([Greek: to/ t' e)pi\ pa=si koino\n kai\ to\ e)pi\ tou/tois, ô(=| to\ e)/stin e)ponoma/zeis kai\ to\ ou)k e)/stin], p. 185 C).

When Plato thus narrows the sense of [Greek: ai)/sthêsis], it is easy to prove that [Greek: e)pistê/mê] is not [Greek: ai)/sthêsis]; but I doubt whether those who affirmed this proposition intended what he here refutes. Neither unreflecting men, nor early theorizers, would distinguish the impressions of sense from the feeling of such impressions being _successive, distinct from one another, resembling, &c._ Mr. John Stuart Mill observes (Logic, Book i. chap. iii. sects. 10-13)--"The simplest of all relations are those expressed by the words antecedent and consequent, and by the word simultaneous. If we say dawn preceded sunrise, the fact in which the two things dawn and sunrise were jointly concerned, consisted only of the two things themselves. No third thing entered into the fact or phenomenon at all, unless indeed we choose to call the succession of the two objects a third thing; _but their succession is not something added to the things themselves_, it is something _involved in them_. To have two feelings at all, implies having them either successively or simultaneously. The relations of succession and simultaneity, of likeness and unlikeness, not being grounded on any fact or phenomenon distinct from the related objects themselves, do not admit of the same kind of analysis. But these relations, though not (like other relations) grounded on states of consciousness, are themselves states of consciousness. Resemblance is nothing but our feeling of resemblance: succession is nothing but our feeling of succession."

By all ordinary (non-theorising) persons, these familiar relations, _involved_ in the facts of sense, are conceived as an essential part of [Greek: ai)/sthêsis]: and are so conceived by those modern theorists who trace all our knowledge to sense--as well as (probably) by those ancient theorists who defined [Greek: e)pistê/mê] to be [Greek: ai)/sthêsis], and against whom Plato here reasons. These theorists would have said (as ordinary language recognises)--"We _see_ the _dissimilarity_ of the black hands from the white face of the clock; we _hear_ the _likeness_ of one stroke of the clock to another, and the _succession_ of the strokes one, two, three, one after the other".

The reasoning of Plato against these opponents is thus open to many of the remarks made by Sir William Hamilton, in the notes to his edition of Reid's works, upon Reid's objections against Locke and Berkeley: Reid restricted the word Sensation to a much narrower meaning than that given to it by Locke and Berkeley. "Berkeley's _Sensation_" (observes S. W. Hamilton) "was equivalent to Reid's _Sensation_ plus _Perception_. This is manifest even by the passages adduced in the text" (note to p. 289). But Reid in his remarks omits to notice this difference in the meaning of the same word. The case is similar with Plato when he refutes those who held the doctrine [Greek: E)pistê/mê = Ai)/sthêsis]. The last-mentioned word, in his construction, includes only a part of the meaning which they attributed to it; but he takes no notice of this verbal difference. Sir William Hamilton remarks, respecting M. Royer Collard's doctrine, which narrows prodigiously the province of Sense,--"_Sense_ he so limits that, if rigorously carried out, no sensible perception, as no consciousness, could be brought to bear". This is exactly true about Plato's doctrine narrowing [Greek: ai)/sthêsis]. See Hamilton's edit. of Reid, Appendix, p. 844.

Aristotle understands [Greek: ai)/sthêsis--ai)sthêtikê\ psuchê\] or [Greek: zôê/]--as occupying a larger sphere than that which Plato assigns to them in the Theætêtus. Aristotle recognises the five separate [Greek: ai)sthê/seis], each correlating with and perceiving its [Greek: i)/dion ai)sthêto/n]: he also recognises [Greek: ê( koinê\ ai)/sthêsis]--common sensation or perception--correlating with (or perceiving) [Greek: ta\ koina\ ai)sthêta/], which are _motion_, _rest_, _magnitude_, _figure_, _number_. The [Greek: koinê\ ai)/sthêsis] is not a distinct or sixth sense, apart from the five, but a general power inhering in all of them. He farther recognises [Greek: ai)/sthêsis] as discriminating, judging, comparing, knowing: this characteristic, [Greek: to\ kritoko\n] and [Greek: gnôstiko/n], is common to [Greek: ai)/sthêsis, phantasi/a, no/êsis], and distinguishes them all from appetite--[Greek: to\ o)rektiko/n, kinêtiko/n], &c. See the first and second chapters of the third Book of the Treatise De Animâ, and the Commentary of Simplikius upon that Treatise, especially p. 56, b. Aristotle tells us that all animals [Greek: e)/chei du/namin su/mphuton kritikê/n, ê(\n kalou=sin ai)/sthêsin.] Anal. Poster. ii. p. 99, b. 35. And Sir William Hamilton adopts a similar view, when he remarks, that Judgment is implied in every act of Consciousness.

Occasionally indeed Aristotle partitions the soul between [Greek: nou=s] and [Greek: o)/rexis]--Intelligence and Appetite--recognising Sense as belonging to the head of Intelligence--see De Motu Animalium, 6, p. 700, b. 20. [Greek: tau=ta de\ pa/nta a)na/getai ei)s nou=n kai\ o)/rexin; kai\ ga\r ê( phantasi/a kai\ ê( ai)/sthêsis tê\n au)tê\n tô=| nô=| chô/ran e)/chousi; _kritika\ ga\r pa/nta_.] Compare also the Topica, ii. 4, p. 111, a. 18.

It will thus be seen that while Plato severs pointedly [Greek: ai)/sthêsis] from anything like discrimination, comparison, judgment, even in the most rudimentary form--Aristotle refuses to adopt this extreme abstraction as his basis for classifying the mental phenomena. He recognises a certain measure of discrimination, comparison, and judgment, as implicated in sensible perceptions. Moreover, that which he calls [Greek: koinê\ ai)/sthêsis] is unknown to Plato, who isolates each sense, and indeed each act of each sense, as much as possible. Aristotle is opposed, as Plato is, to the doctrine [Greek: E)pistê/mê = Ai)/sthêsis], but he employs a different manner of reasoning against it. See, _inter alia_, Anal. Poster. i. 31, p. 87, b. 28. He confines [Greek: e)pistê/mê] to one branch of the [Greek: noêtikê/].

The Peripatetic Straton, the disciple of Theophrastus, denied that there was any distinct line of demarcation between [Greek: to\ ai)stha/nesthai] and [Greek: to\ noei=n]: maintaining that the former was impossible without a certain measure of the latter. His observation is very worthy of note. Plutarch, De Solertiâ Animalium, iii. 6, p. 961 A. [Greek: Kai/toi Stra/tôno/s ge tou= phusikou= lo/gos e)sti/n, a)podeiknu/ôn ô(s ou)d' ai)stha/nesthai topara/pan a)/neu tou= noei=n u(pa/rchei; kai\ ga\r gra/mmata polla/kis e)piporeuo/mena tê=| o)/psei, kai\ lo/goi prospi/ptontes tê=| a)koiê=| _dialantha/nousin ê(ma=s_ kai\ _diapheu/gousi pro\s e(te/rois to\n nou=n e)/chontas_; ei)=t' _au)=this e)panê=lthe_ kai\ _metathei= kai\ metadiô/kei tô=n proïeme/nôn e(/kaston a)nalego/menos_; ê(=| kai\ le/lektai. _Nou=s o(rê=|, kai\ nou=s a)kou/ei, ta\ de\ a)/lla kôpha\ kai\ tuphla/_;** ô(s tou= peri\ ta\ o)/mmata kai\ ô)=ta pa/thous, a)\n mê\ parê=| to\ phronou=n, ai)/sthêsin ou) poiou=ntos.]

Straton here notices that remarkable fact (unnoticed by Plato and even by Aristotle, so far as I know) in the process of association, that impressions of sense are sometimes unheeded when they occur, but force themselves upon the attention afterwards, and are recalled by the mind in the order in which they occurred at first.]

[Footnote 100: Plato, Theæt. p. 187 A. _Sokr._ [Greek: o(/môs de\ tosou=to/n ge probebê/kamen, ô(/ste mê\ zêtei=n au)tê\n (e)pistê/mên) e)n ai)sthê/sei topara/pan, a)ll' e)n e)kei/nô| tô=| o)no/mati, o(/, ti pot' e)/chei ê( psuchê/, o(/tan au)tê\ kath' au(tê\n pragmateu/êtai peri\ ta\ o)/nta.] _Theæt._ [Greek: A)lla\ mê\n tou=to/ ge kalei=tai, ô(s e)gô)=|mai, _doxa/zein_.] _Sokr._ [Greek: O)rthô=s ga\r oi)/ei.]

Plato is quite right in distinguishing between [Greek: ai)/sthêsis] and [Greek: do/xa], looking at the point as a question of psychological classification. It appears to me, however, most probable that those who maintained the theory [Greek: E)pistê/mê = Ai)/sthêsis], made no such distinction, but included that which he calls [Greek: do/xa] in [Greek: ai)/sthêsis]. Unfortunately we do not possess their own exposition; but it cannot have included much of psychological analysis.]

[Footnote 101: Schleiermacher represents Plato as discriminating Knowledge (the region of infallibility, you either possess it or not) from Opinion (the region of fallibility, true or false, as the case may be) by a broad and impassable line--

"Auch hieraus erwächst eine sehr entscheidende, nur ebenfalls nicht ausdrücklich gezogene, Folgerung, dass die reine Erkenntniss gar nicht auf demselben Gebiet liegen könne mit dem Irrthum--und es in Beziehung auf sie kein Wahr und Falsch gebe, sondern nur ein Haben oder Nicht Haben." (Schleiermacher, Einleit. zum Theæt. p. 176.)

Steinhart (in his Einleit. zum Theæt. p. 94) contests this opinion of Schleiermacher (though he seems to give the same opinion himself, p. 92). He thinks that Plato does not recognise so very marked a separation between Knowledge and Opinion: that he considers Knowledge as the last term of a series of mental processes, developed gradually according to constant laws, and ascending from Sensible Perception through Opinion to Knowledge: that the purpose of the Theætêtus is to illustrate this theory.

Ueberweg, on the contrary, defends the opinion of Schleiermacher and maintains that Steinhart is mistaken (Aechtheit und Zeit. Platon. Schriften, p. 279).

Passages may be produced from Plato's writings to support both these views: that of Schleiermacher, as well as that of Steinhart. In Timæus, p. 51 E, the like infallibility is postulated for [Greek: Nou=s] (which there represents [Greek: E)pistê/mê]) as contrasted with [Greek: do/xa]. But I think that Steinhart ascribes to the Theætêtus more than can fairly be discovered in it. That dialogue is purely negative. It declares that [Greek: e)pistê/mê] is _not_ [Greek: ai)/sthêsis]. It then attempts to go a step farther towards the affirmative, by declaring also that [Greek: e)pistê/mê] is a mental process of computation, respecting the impressions of [Greek: ai)/sthêsis]--that it is [Greek: to\ sullogi/zesthai], which is equivalent to [Greek: to\ doxa/zein]: compare Phædrus, 249 B. But this affirmative attempt breaks down: for Sokrates cannot explain what [Greek: to\ doxa/zein] is, nor how [Greek: to\ doxa/zein pseudê=] is possible; in fact he says (p. 200 B) that this cannot be explained until we know what [Greek: e)pistê/mê] is. The entire result of the dialogue is negative, as the closing words proclaim emphatically. On this point many of the commentators agree--Ast, Socher, Stallbaum, Ueberweg, Zeller, &c.

Whether it be true, as Schleiermacher, with several others, thinks (Einl. pp. 184-185), that Plato intends to attack Aristippus in the first part of the dialogue, and Antisthenes in the latter part, we have no means of determining.]

This at least is the meaning which Plato assigns to the two words corresponding to Cognition and to Opinion, in the present dialogue, and often elsewhere. But he also frequently employs the word Cognition in a lower and more general signification, not restricted, as it is here, to the highest philosophical reach, with infallibility--but comprehending much of what is here treated only as _opinion_. Thus, for example, he often alludes to the various professional men as possessing _Cognition_, each in his respective department: the general, the physician, the gymnast, the steersman, the husbandman, &c.[102] But he certainly does not mean, that each of them has attained what he calls real essence and philosophical truths--or that any of them are infallible.

[Footnote 102: Compare Plato, Sophistes, pp. 232 E, 233 A.]

[Side-note: Plato did not recognise Verification from experience, or from facts of sense, as either necessary or possible.]

One farther remark must be made on Plato's doctrine. His remark--That Cognition consists not in the affections of sense, but in computation or reasoning respecting those affections, (_i. e._ abstraction, generalisation, &c.)--is both true and important. But he has not added, nor would he have admitted, that if we are to decide whether our computation is true and right, or false and erroneous--our surest way is to recur to the simple facts of sense. Theory must be verified by observation; wherever that cannot be done, the best guarantee is wanting. The facts themselves are not cognition: yet they are the test by which all computations, pretending to be cognitions, must be tried.[103]

[Footnote 103: See the remarks on the necessity of Verification, as a guarantee for the Deductive Process, in Mr. John Stuart Mill's System of Logic, Book iii. ch. xi. s. 8. Newton puts aside his own computation or theory respecting gravity as the force which kept the moon in its orbit, because the facts reported by observers respecting the lunar motions were for some time not in harmony with it. Plato certainly would not have surrendered any [Greek: sullogismo\s] under the same respect to observed facts. Aristotle might probably have done so; but this is uncertain.]

[Side-note: Second definition given by Theætêtus--That Cognition consists in right or true opinion.]

We have thus, in enquiring--What is Knowledge or Cognition? advanced so far as to discover--That it does not consist in sensible perception, but in some variety of that purely mental process which is called opining, believing, judging, conceiving, &c. And here Theætêtus, being called upon for a second definition, answers--_That Knowledge consists in right or true opinion_. All opinion is not knowledge, because opinion is often false.[104]

[Footnote 104: Plato, Theæt. p. 187 B. It is scarcely possible to translate [Greek: doxa/zein] always by the same English word.]

[Side-note: Objection by Sokrates--This definition assumes that there are false opinions. But how can false opinions be possible? How can we conceive Non-Ens: or confound together two distinct realities?.]

_Sokr._--But you are here assuming that there _are_ false opinions? How is this possible? How can any man judge or opine falsely? What mental condition is it which bears that name? I confess that I cannot tell: though I have often thought of the matter myself, and debated it with others.[105] Every thing comes under the head either of what a man knows, or of what he does not know. If he conceives, it must be either the known, or the unknown. He cannot mistake either one known thing for another known thing: or a known thing for an unknown: or an unknown for a known: or one unknown for another unknown. But to form a false opinion, he must err in one or other of these four ways. It is therefore impossible that he can form a false opinion.[106]

[Footnote 105: Plato, Theæt. p. 187 C.]

[Footnote 106: Plato, Theæt. p. 188.]

If indeed a man ascribed to any subject a predicate which was non-existent, this would be evidently a false opinion. But how can any one conceive the non-existent? He who conceives must conceive _something_: just as he who sees or touches, must see or touch _something_. He cannot see or touch the non-existent: for that would be to see or touch nothing: in other words, not to see or touch at all. In the same manner, to conceive the non-existent, or _nothing_, is impossible.[107] _Theæt._--Perhaps he conceives two realities, but confounds them together, mistaking the one for the other. _Sokr._--Impossible. If he conceives two distinct realities, he cannot suppose the one to be the other. Suppose him to conceive, just and unjust, a horse and an ox--he can never believe just to be unjust, or the ox to be the horse.[108] If, again, he conceives one of the two alone and singly, neither could he on that hypothesis suppose it to be the other: for that would imply that he conceived the other also.

[Footnote 107: Plato, Theæt. p. 188-189.]

[Footnote 108: Plato, Theæt. p. 190.]

[Side-note: Waxen memorial tablet in the mind, on which past impressions are engraved. False opinion consists in wrongly identifying present sensations with past impressions.]

Let us look again in another direction (continues Sokrates). We have been hasty in our concessions. Is it really impossible for a man to conceive, that a thing, which he knows, is another thing which he does not know? Let us see. Grant me the hypothesis (for the sake of illustration), that each man has in his mind a waxen tablet--the wax of one tablet being larger, firmer, cleaner, and better in every way, than that of another: the gift of Mnemosynê, for inscribing and registering our sensible perceptions and thoughts. Every man remembers and knows these, so long as the impressions of them remain upon his tablet: as soon as they are blotted out, he has forgotten them and no longer knows them.[109] Now false opinion may occur thus. A man having inscribed on his memorial tablet the impressions of two objects A and B, which he has seen before, may come to see one of these objects again; but he may by mistake identify the present sensation with the wrong past impression, or with that past impression to which it does not belong. Thus on seeing A, he may erroneously identify it with the past impression B, instead of A: or _vice versâ_.[110] False opinion will thus lie, not in the conjunction or identification of sensations with sensations--nor of thoughts (or past impressions) with thoughts--but in that of present sensations with past impressions or thoughts.[111]

[Footnote 109: Plato, Theæt. p. 191 C. [Greek: kê/rinon e)kmogei=on].]

[Footnote 110: Plato, Theæt. p. 193-194.]

[Footnote 111: Plato, Theæt. p. 195 D.]

[Side-note: Sokrates refutes this assumption. Dilemma. Either false opinion is impossible, or else a man may know what he does not know.]

Having laid this down, however, Sokrates immediately proceeds to refute it. In point of fact, false conceptions are found to prevail, not only in the wrong identification of present sensations with past impressions or thoughts, but also in the wrong identification of one past impression or thought with another. Thus a man, who has clearly engraved on his memorial tablet the conceptions of five, seven, eleven, twelve,--may nevertheless, when asked what is the sum of seven and five, commit error and answer eleven: thus mistaking eleven for twelve.

We are thus placed in this dilemma--Either false opinion is an impossibility:--Or else, it is possible that what a man knows, he may not know. Which of the two do you choose?[112]

[Footnote 112: Plato, Theæt. p. 196 C. [Greek: nu=n de\ ê)/toi ou)k e)/sti pseudê\s do/xa, ê)\ a(/ tis oi)=den, oi(=o/n te mê\ ei)de/nai; kai\ tou/tôn po/tera ai(rei=?]]

[Side-note: He draws distinction between possessing knowledge, and having it actually in hand. Simile of the pigeon-cage with caught pigeons turned into it and flying about.]

To this question no answer is given. But Sokrates,--after remarking on the confused and unphilosophical manner in which the debate has been conducted, both he and Theætêtus having perpetually employed the words _know_, _knowledge_, and their equivalents, as if the meaning of the words were ascertained, whereas the very problem debated is, to ascertain their meaning[113]--takes up another path of enquiry. He distinguishes between possessing knowledge,--and having it actually in hand or on his person: which distinction he illustrates by comparing the mind to a pigeon-cage. A man hunts and catches pigeons, then turns them into the cage, within the limits of which they fly about: when he wants to catch any one of them for use, he has to go through a second hunt, sometimes very troublesome: in which he may perhaps either fail altogether, or catch the wrong one instead of the right. The first hunt Sokrates compares to the acquisition of knowledge: the second, to the getting it into his hand for use.[114] A man may _know_, in the first sense, and _not know_, in the second: he may have to hunt about for the cognition which (in the first sense) he actually possesses. In trying to catch one cognition, he may confound it with another: and this constitutes false opinion--the confusion of two _cognita_ one with another.[115]

[Footnote 113: Plato, Theæt. p. 196 D.]

[Footnote 114: Plato, Theæt. p. 197-198.]

[Footnote 115: Plato, Theæt. p. 199 C. [Greek: ê( tô=n e)pistêmô=n metallagê/].]

[Side-note: Sokrates refutes this. Suggestion of Theætêtus--That there may be non-cognitions in the mind as well as cognitions, and that false opinion may consist in confounding one with the other. Sokrates rejects this.]

Yet how can such a confusion be possible? (Sokrates here again replies to himself.) How can knowledge betray a man into such error? If he knows A, and knows B--how can he mistake A for B? Upon this supposition, knowledge produces the effect of ignorance: and we might just as reasonably imagine ignorance to produce the effects of knowledge.[116]--Perhaps (suggests Theætêtus), he may have _non-cognitions_ in his mind, mingled with the cognitions: and in hunting for a cognition, he may catch a non-cognition. Herein may lie false opinion.--That can hardly be (replies Sokrates). If the man catches what is really a non-cognition, he will not suppose it to be such, but to be a cognition. He will believe himself fully to _know_, that in which he is mistaken. But how is it possible that he should confound a non-cognition with a cognition, or _vice versâ_? Does not he know the one from the other? We must then require him to have a separate cognition of his own cognitions or non-cognitions--and so on _ad infinitum_.[117] The hypothesis cannot be admitted.

[Footnote 116: Plato, Theæt. p. 199 E.]

[Footnote 117: Plato, Theæt. p. 200 B.]

We cannot find out (continues Sokrates) what false opinion is: and we have plainly done wrong to search for it, until we have first ascertained what knowledge is.[118]

[Footnote 118: Plato, Theæt. p. 200 C.]

[Side-note: He brings another argument to prove that Cognition is not the same as true opinion. Rhetors persuade or communicate true opinion; but they do not teach or communicate knowledge.]

Moreover, as to the question, Whether knowledge is identical with true opinion, Sokrates produces another argument to prove that it is not so: and that the two are widely different. You can communicate true opinion without communicating knowledge: and the powerful class of rhetors and litigants make it their special business to do so. They persuade, without teaching, a numerous audience.[119] During the hour allotted to them for discourse, they create, in the minds of the assembled dikasts, true opinions respecting complicated incidents of robbery or other unlawfulness, at which none of the dikasts have been personally present. Upon this opinion the dikasts decide, and decide rightly. But they cannot possibly _know_ the facts without having been personally present and looking on. That is essential to knowledge or cognition.[120] Accordingly, they have acquired true and right opinions; yet without acquiring knowledge. Therefore the two are not the same.[121]

[Footnote 119: Plato, Theæt. p. 201 A. [Greek: ou(=toi ga/r pou tê=| e(autô=n te/chnê| pei/thousin, ou) dida/skontes, a)lla\ doxa/zein poiou=ntes a(\ a)\n bou/lôntai.]]

[Footnote 120: Plato, Theæt. p. 201 B-C. [Greek: Ou)kou=n o(/tan dikai/ôs peisthô=si dikastai\ peri\ _ô(=n i)do/nti mo/non e)/stin ei)de/nai, a)/llôs de\ mê/_, tau=ta to/te _e)x a)koê=s kri/nontes_, a)lêthê= do/xan labo/ntes, a)/neu e)pistê/mês e)/krinan, o)rtha\ peisthe/ntes, ei)/per eu)= e)di/kasan?]]

[Footnote 121: The distinction between persuading and teaching--between creating opinion and imparting knowledge--has been brought to view in the Gorgias, and is noted also in the Timæus. As it stands here, it deserves notice, because Plato not only professes to affirm what _knowledge_ is, but also identifies it with sensible perception. The Dikasts (according to Sokrates) would have _known_ the case, had they been present when it occurred, so as to see and hear it: there is no other way of acquiring knowledge.

Hearing the case only by the narration of speakers, they can acquire nothing more than a _true opinion_. Hence we learn wherein consists the difference between the two. That which I see, hear, or apprehend by any sensible perception, I _know_: compare a passage in Sophistes, p. 267 A-B, where [Greek: to\ gignô/skein] is explained in the same way. But that which I learn from the testimony of others amounts to nothing more than opinion; and at best to a true opinion.

Plato's reasoning here involves an admission of the very doctrine which he had before taken so much pains to confute--the doctrine that Cognition is Sensible Perception. Yet he takes no notice of the inconsistency. An occasion for sneering at the Rhetors and Dikasts is always tempting to him.

So, in the Menon (p. 97 B), the man who has been at Larissa is said to _know_ the road to Larissa; as distinguished from another man who, never having been there, opines correctly which the road is. And in the Sophistes (p. 263) when Plato is illustrating the doctrine that false propositions, as well as true propositions, are possible, and really occur, he selects as his cases, [Greek: Theai/têtos ka/thêtai, Theai/têtos pe/tetai]. That one of these propositions is false and the other true, can be known only by [Greek: ai)/sthêsis]--in the sense of that word commonly understood.]

[Side-note: New answer of Theætêtus--Cognition is true opinion, coupled with rational explanation.]

Theætêtus now recollects another definition of knowledge, learnt from some one whose name he forgets. Knowledge is (he says) true opinion, coupled with rational explanation. True opinion without such rational explanation, is not knowledge. Those things which do not admit of rational explanation, are not knowable.[122]

[Footnote 122: Plato, Theætêt. p. 201 D. [Greek: tê\n me\n meta\ lo/gou a)lêthê= do/xan e)pistê/mên ei)=nai; tê\n de\ a)/logon, e)kto\s e)pistê/mês; kai\ ô(=n me\n mê/ e)sti lo/gos, ou)k e)pistêta\ ei)=nai, _ou(tôsi\ kai\ o)noma/zôn_, a)\ d' e)/chei, e)pistêta/.]

The words [Greek: ou(tôsi\ kai\ o)noma/zôn] are intended, according to Heindorf and Schleiermacher, to justify the use of the word [Greek: e)pistêta/], which was then a neologism. Both this definition, and the elucidation of it which Sokrates proceeds to furnish, are announced as borrowed from other persons not named.]

[Side-note: Criticism on the answer by Sokrates. Analogy of letters and words, primordial elements and compounds. Elements cannot be explained: compounds alone can be explained.]

Taking up this definition, and elucidating it farther, Sokrates refers to the analogy of words and letters. Letters answer to the primordial elements of things; which are not matters either of knowledge, or of true opinion, or of rational explanation--but simply of sensible perception. A letter, or a primordial element, can only be perceived and called by its name. You cannot affirm of it any predicate or any epithet: you cannot call it _existing_, or _this_, or _that_, or _each_, or _single_, or by any other name than its own:[123] for if you do, you attach to it something extraneous to itself, and then it ceases to be an element. But syllables, words, propositions--_i. e._, the compounds made up by putting together various letters or elements--admit of being known, explained, and described, by enumerating the component elements. You may indeed conceive them correctly, without being able to explain them or to enumerate their component elements: but then you do not know them. You can only be said to know them, when besides conceiving them correctly, you can also specify their component elements[124]--or give explanation.

[Footnote 123: Plato, Theæt. pp. 201 E--202 A. [Greek: au)to\ ga\r kath' au(to\ e(/kaston o)noma/sai mo/non ei)/ê, proseipei=n de\ ou)de\n a)/llo dunato/n, ou)/th' ô(s e)/stin, ou)/th' ô(s ou)k e)/stin' ê)/dê ga\r a)\n ou)si/an ê)\ mê\ ou)si/an au)tô=| prosti/thesthai, dei=n de\ ou)de\n prosphe/rein, ei)/per au)to\ e)kei=no mo/non tis e)rei=; e)pei\ ou)de\ to\ _au)to/_, ou)de/ to\ _e)kei=no_, ou)de\ to _e(/kaston_, ou)de\ to _mo/non_, ou)de\ to\ _tou=to_, prosoiste/on, ou)d' a)/lla polla\ toiau=ta; tau=ta me\n ga\r peritre/chonta pa=si prosphe/resthai, e(/tera o)/nta e(kei/nôn oi(=s prosti/thetai.] Also p. 205 C.]

[Footnote 124: Plato, Theæt. p. 202.]

[Side-note: Sokrates refutes this criticism. If the elements are unknowable, the compound must be unknowable also.]

Having enunciated this definition, as one learnt from another person not named, Sokrates proceeds to examine and confute it. It rests on the assumption (he says), that the primordial elements are themselves unknowable; and that it is only the aggregates compounded of them which are knowable. Such an assumption cannot be granted. The result is either a real sum total, including both the two component elements: or it is a new form, indivisible and uncompounded, generated by the two elements, but not identical with them nor including them in itself. If the former, it is not knowable, because if neither of the elements are knowable, both together are not knowable: when you know neither A nor B you cannot know either the sum or the product of A and B. If the latter, then the result, being indivisible and uncompounded, is unknowable for the same reason as the elements are so: it can only be named by its own substantive name, but nothing can be predicated respecting it.[125]

[Footnote 125: Plato, Theæt. pp. 203-206.]

Nor can it indeed be admitted as true--That the elements are unknowable, and the compound alone knowable. On the contrary, the elements are more knowable than the compound.[126]

[Footnote 126: Plato, Theæt. p. 206.]

[Side-note: Rational explanation may have one of three different meanings. 1. Description in appropriate language. 2. Enumeration of all the component elements in the compound. In neither of these meanings will the definition of Cognition hold.]

When you say (continues Sokrates) that knowledge is true opinion coupled with rational explanation, you may mean by _rational explanation_ one of three things. 1. The power of enunciating the opinion in clear and appropriate words. This every one learns to do, who is not dumb or an idiot: so that in this sense true opinion will always carry with it rational explanation.--2. The power of describing the thing in question by its component elements. Thus Hesiod says that there are a hundred distinct wooden pieces in a waggon: you and I do not know nor can we describe them all: we can distinguish only the more obvious fractions--the wheels, the axle, the body, the yoke, &c. Accordingly, we cannot be said to know a waggon: we have only a true opinion about it. Such is the second sense of [Greek: lo/gos] or rational explanation. But neither in this sense will the proposition hold--That knowledge is right opinion coupled with rational explanation. For suppose that a man can enumerate, spell, and write correctly, all the syllables of the name _Theætêtus_--which would fulfil the conditions of this definition: yet, if he mistakes and spells wrongly in any other name, such as _Theodôrus_, you will not give him credit for knowledge. You will say that he writes _Theætêtus_ correctly, by virtue of right opinion simply. It is therefore possible to have right opinion coupled with rational explanation, in this second sense also,--yet without possessing knowledge.[127]

[Footnote 127: Plato, Theæt. p. 207-208 B. [Greek: e)/stin a)/ra meta\ lo/gou o)rthê\ do/xa, ê(\n ou)/pô dei= _e)pistê/mên_ kalei=n.]]

[Side-note: Third meaning. To assign some mark, whereby the thing to be explained differs from everything else. The definition will not hold. For rational explanation, in this sense, is already included in true opinion.]

3. A third meaning of this same word [Greek: lo/gos] or rational explanation, is, that in which it is most commonly understood-To be able to assign some mark whereby the thing to be explained differs from every thing else--to differentiate the thing.[128] Persons, who understand the word in this way, affirm, that so long as you only seize what the thing has in common with other things, you have only a _true opinion_ concerning it: but when you seize what it has peculiar and characteristic, you then possess _knowledge_ of it. Such is their view: but though it seems plausible at first sight (says Sokrates), it will not bear close scrutiny. For in order to have a true opinion about any thing, I must have in my mind not only what it possesses in common with other things, but what it possesses peculiar to itself also. Thus if I have a true opinion about Theætêtus, I must have in my mind not only the attributes which belong to him in common with other men, but also those which belong to him specially and exclusively. Rational explanation ([Greek: lo/gos]) in this sense is already comprehended in true opinion, and is an essential ingredient in it--not any new element superadded. It will not serve therefore as a distinction between true opinion and knowledge.[129]

[Footnote 128: Plato, Theætêt. p. 208 C. [Greek: O(/per a)\n oi( polloi\ ei)/poien, to\ e)/chein ti sêmei=on ei)pei=n ô(=| tô=n a(pa/ntôn diaphe/rei to\ e)rôtêthe/n.]]

[Footnote 129: Plato, Theætêt. p. 209.]

[Side-note: Conclusion of the dialogue--Summing up by Sokrates--Value of the result, although purely negative.]

Such is the result (continues Sokrates) of our researches concerning knowledge. We have found that it is neither sensible perception--nor true opinion--nor true opinion along with rational explanation. But what it is, we have not found. Are we still pregnant with any other answer, Theætêtus, or have we brought forth all that is to come?--_I_ have brought forth (replies Theætêtus) more than I had within me, through your furtherance. Well (rejoins Sokrates)--and my obstetric science has pronounced all your offspring to be mere wind, unworthy of being preserved![130] If hereafter you should again become pregnant, your offspring will be all the better for our recent investigation. If on the other hand you should always remain barren, you will be more amiable and less vexatious to your companions--by having a just estimate of yourself and by not believing yourself to know what you really do not know.[131]

[Footnote 130: Plato, Theætêt. p. 210 B. [Greek: ou)kou=n tau=ta me\n a(/panta ê( maieutikê\ ê(mi=n te/chnê a)nemiai=a/ phêsi gegenê=sthai kai\ ou)k a)/xia trophê=s?]]

[Footnote 131: Plato, Theæt. p. 210 C. [Greek: e)a/n te gi/gnê| (e)gku/môn), beltio/nôn e)/sei plê/rês dia\ tê\n nu=n e)xe/tasin; e)a/n te keno\s ê)=s, ê(=tton e)/sei baru\s toi=s sunou=si kai\ ê(merô/teros, sôphro/nôs ou)k oi)o/menos ei)de/nai a(\ mê\ oi)=stha.]

Compare also an earlier passage in the dialogue, p. 187 B.]

* * * * *

[Side-note: Remarks on the dialogue. View of Plato. False persuasion of knowledge removed. Importance of such removal.]

The concluding observations of this elaborate dialogue deserve particular attention as illustrating Plato's point of view, at the time when he composed the Theætêtus. After a long debate, set forth with all the charm of Plato's style, no result is attained. Three different explanations of knowledge have been rejected as untenable.[132] No other can be found; nor is any suggestion offered, showing in what quarter we are to look for the true one. What then is the purpose or value of the dialogue? Many persons would pronounce it to be a mere piece of useless ingenuity and elegance: but such is not the opinion of Plato himself. Sufficient gain (in his view) will have been ensured, if Theætêtus has acquired a greater power of testing any fresh explanation which he may attempt of this difficult subject: or even if he should attempt none such, by his being disabused, at all events, of the false persuasion of knowing where he is really ignorant. Such false persuasion of knowledge (Plato here intimates) renders a man vexatious to associates; while a right estimate of his own knowledge and ignorance fosters gentleness and moderation of character. In this view, false persuasion of knowledge is an ethical defect, productive of positive mischief in a man's intercourse with others: the removal of it improves his character, even though no ulterior step towards real and positive knowledge be made. The important thing is, that he should acquire the power of testing and verifying all opinions, old as well as new. This, which is the only guarantee against the delusive self-satisfaction of sham knowledge, must be firmly established in the mind before it is possible to aspire effectively to positive and assured knowledge. The negative arm of philosophy is in its application prior to the positive, and indispensable, as the single protection against error and false persuasion of knowledge. Sokrates is here depicted as one in whom the negative vein is spontaneous and abundant, even to a pitch of discomfort--as one complaining bitterly, that objections thrust themselves upon him, unsought and unwelcome, against conclusions which he had himself just previously taken pains to prove at length.[133]

[Footnote 132: I have already observed, however, that in one passage of the interrogation carried on by Sokrates (p. 201 A-B, where he is distinguishing between persuasion and teaching) he unconsciously admits the identity between knowledge and sensible perception.]

[Footnote 133: See the emphatic passage, p. 195 B-C.]

[Side-note: Formation of the testing or verifying power in men's minds, value of the Theætêtus, as it exhibits Sokrates demolishing his own suggestions.]

To form in men's minds this testing or verifying power, is one main purpose in Plato's dialogues of Search--and in some of them the predominant purpose; as he himself announces it to be in the Theætêtus. I have already made the same remark before, and I repeat it here; since it is absolutely necessary for appreciating these dialogues of Search in their true bearing and value. To one who does not take account of the negative arm of philosophy, as an auxiliary without which the positive arm will strike at random--half of the Platonic dialogues will teach nothing, and will even appear as enigmas--the Theætêtus among the foremost. Plato excites and strengthens the interior mental wakefulness of the hearer, to judge respecting all affirmative theories, whether coming from himself or from others. This purpose is well served by the manner in which Sokrates more than once in this dialogue first announces, proves, and builds up a theory--then unexpectedly changes his front, disproves, and demolishes it. We are taught that it is not difficult to find a certain stock of affirmative argument which makes the theory look well from a distance: we must inspect closely, and make sure that there are no counter-arguments in the background.[134] The way in which Sokrates pulls to pieces his own theories, is farther instructive, as it illustrates the exhortation previously addressed by him to Theætêtus--not to take offence when his answers were canvassed and shown to be inadmissible.[135]

[Footnote 134: Plato, Theætêt. p. 208 E.]

[Footnote 135: Plato, Theætêt. p. 151 C.]

[Side-note: Comparison of the Philosopher with the Rhetor. The Rhetor is enslaved to the opinions of auditors.]

A portion of the dialogue to which I have not yet adverted, illustrates this anxiety for the preliminary training of the ratiocinative power, as an indispensable qualification for any special research. "We have plenty of leisure for investigation[136] (says Sokrates). We are not tied to time, nor compelled to march briefly and directly towards some positive result. Engaged as we are in investigating philosophical truth, we stand in pointed contrast with politicians and rhetors in the public assembly or dikastery. We are like freemen; they, like slaves. They have before them the Dikasts, as their masters, to whose temper and approbation they are constrained to adapt themselves. They are also in presence of antagonists, ready to entrap and confute them. The personal interests, sometimes even the life, of an individual are at stake; so that every thing must be sacrificed to the purpose of obtaining a verdict. Men brought up in these habits become sharp in observation and emphatic in expression; but merely with a view to win the assent and approbation of the master before them, as to the case in hand. No free aspirations or spontaneous enlargement can have place in their minds. They become careless of true and sound reasoning--slaves to the sentiment of those whom they address--and adepts in crooked artifice which they take for wisdom.[137]

[Footnote 136: Plato, Theæt. p. 155. [Greek: ô(s pa/nu pollê\n scholê\n a)/gontes, pa/lin e)panaskepso/metha], &c.; also p. 172.]

[Footnote 137: Plato, Theætêt. p. 172-173.

I give only an abstract of this eloquent passage, not an exact translation. Steinhart (Einleitung zum Theætêt. p. 37) calls it "a sublime Hymn" (einen erhabenen Hymnus). It is a fine piece of poetry or rhetoric, and shows that Plato was by nature quite as rhetorical as the rhetors whom he depreciates--though he had also, besides, other lofty intellectual peculiarities of his own, beyond these rivals.]

[Side-note: The Philosopher is master of his own debates.]

Of all this (continues Sokrates) the genuine philosopher is the reverse. He neither possesses, nor cares to possess, the accomplishments of the lawyer and politician. He takes no interest in the current talk of the city; nor in the scandals afloat against individual persons. He does not share in the common ardour for acquiring power or money; nor does he account potentates either happier or more estimable for possessing them. Being ignorant and incompetent in the affairs of citizenship as well as of common life, he has no taste for club-meetings or joviality. His mind, despising the particular and the practical, is absorbed in constant theoretical research respecting universals. He spares no labour in investigating--What is man in general? and what are the attributes, active and passive, which distinguish man from other things? He will be overthrown and humiliated before the Dikastery by a clever rhetor. But if this opponent chooses to ascend out of the region of speciality, and the particular ground of injustice alleged by A against B--into the general question, What is justice or injustice? Wherein do they differ from each other or from other things? What constitutes happiness and misery? How is the one to be attained and the other avoided?--If the rhetor will meet the philosopher on this elevated ground, then he will find himself put to shame and proved to be incompetent, in spite of all the acute stratagems of his petty mind.[138] He will look like a child and become ashamed of himself:[139] but the philosopher is noway ashamed of his incompetence for slavish pursuits, while he is passing a life of freedom and leisure among his own dialectics.[140]

[Footnote 138: Plato, Theæt. pp. 175-176.]

[Footnote 139: Plato, Theæt. p. 177 B.]

[Footnote 140: Plato, Theæt. p. 175 E.]

[Side-note: Purpose of dialogue to qualify for a life of philosophical Search.]

In these words of Sokrates we read a contrast between practice and theory--one of the most eloquent passages in the dialogues--wherein Plato throws overboard the ordinary concerns and purposes both of public and private life, admitting that true philosophers are unfit for them. The passage, while it teaches us caution in receiving his criticisms on the defects of actual statesmen and men of action, informs us at the same time that he regarded philosophy as the only true business of life--the single pursuit worthy to occupy a freeman.[141] This throws light on the purpose of many of his dialogues. He intends to qualify the mind for a life of philosophical research, and with this view to bestow preliminary systematic training on the ratiocinative power. To announce at once his own positive conclusions with their reasons, (as I remarked before) is not his main purpose. A pupil who, having got all these by heart, supposed himself to have completed his course of philosophy, so that nothing farther remained to be done, would fall very short of the Platonic exigency. The life of the philosopher--as Plato here conceives it--is a perpetual search after truth, by dialectic debate and mutual cross-examination between two minds, aiding each other to disembroil that confusion and inconsistency which grows up naturally in the ordinary mind. For such a life a man becomes rather disqualified than prepared, by swallowing an early dose of authoritative dogmas and proofs dictated by his teacher. The two essential requisites for it are, that he should acquire a self-acting ratiocinative power, and an earnest, untiring, interest in the dialectic process. Both these aids Plato's negative dialogues are well calculated to afford: and when we thus look at his purpose, we shall see clearly that it did not require the presentation of any positive result.

[Footnote 141: Plato, Sophistês, p. 253 C: [Greek: ê( tô=n e)leuthe/rôn e)pistê/mê].]

[Side-note: Difficulties of the Theætêtus are not solved in any other Dialogue.]

The course of this dialogue--the Theætêtus--has been already described as an assemblage of successive perplexities without any solution. But what deserves farther notice is--That the perplexities, as they are not solved in this dialogue, so they are not solved in any other dialogue. The view taken by Schleiermacher and other critics--that Plato lays out the difficulties in one anterior dialogue, in order to furnish the solution in another posterior--is not borne out by the facts. In the Theætêtus, many objections are propounded against the doctrine, That Opinion is sometimes true, sometimes false. Sokrates shows that false opinion is an impossibility: either therefore all opinions are true, or no opinion is either true or false. If we turn to the Sophistês, we shall find this same question discussed by the Eleatic Stranger who conducts the debate. He there treats the doctrine--That false opinion is an impossibility and that no opinion could be false--as one which had long embarrassed himself, and which formed the favourite subterfuge of the impostors whom he calls Sophists. He then states that this doctrine of the Sophists was founded on the Parmenidean dictum--That Non-Ens was an impossible supposition. Refuting the dictum of Parmenides (by a course of reasoning which I shall examine elsewhere), he arrives at the conclusion--That Non-Ens exists in a certain fashion, as well as Ens: That false opinions are possible: That there may be false opinions as well as true. But what deserves most notice here, in illustration of Plato's manner, is--that though the Sophistês[142] is announced as a continuation of the Theætêtus (carried on by the same speakers, with the addition of the Eleate), yet the objections taken by Sokrates in the Theætêtus against the possibility of false opinion, are not even noticed in the Sophistês--much less removed. Other objections to it are propounded and dealt with: but not those objections which had arrested the march of Sokrates in the Theætêtus.[143] Sokrates and Theætêtus hear the Eleatic Stranger discussing this same matter in the Sophistês, yet neither of them allude to those objections against his conclusion which had appeared to both of them irresistible in the preceding dialogue known as Theætêtus. Nor are the objections refuted in any other of the Platonic dialogues.

[Footnote 142: See the end of the Theætêtus and the opening of the Sophistês. Note, moreover, that the Politikus makes reference not only to the Sophistês, but also to the Theætêtus (pp. 258 A, 266 D, 284 B, 286 B).]