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

Sokrates refutes this assumption. Dilemma. Either false opinion is impossible, or else a man may know what he does not know.

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

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 meaning113 — 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

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.

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

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

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

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 elements124 — or give explanation.

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

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

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 λόγος 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

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 λόγος 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 (λόγος) 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

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

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

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

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 investigation136 (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

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