and true reason say. Is it not thus necessary to examine into the nature of any thing? In the first place, whether that is simple or manifold about which we are desirous, both ourselves to be skilled, and to be able to make others so; and, in the next place, if it be simple, to examine the power it naturally possesses of acting on each particular thing, or of being acted upon by each particular thing? And if it possesses several species, having enumerated these, as in the case of the one, ought we not to consider this in each of them, what active and passive power they naturally have?
_Phæ._ It seems so, Socrates.
123. _Socr._ The method, then, that neglected these, would resemble the walk of a blind man. He however who proceeds by art, ought on no account to be compared either to a blind or a deaf man; but it is clear that whosoever teaches another speaking by art, should accurately shew the real nature of the things to which he will have to apply his speeches; and this surely is the soul.
_Phæ._ How not?
_Socr._ His whole endeavour, therefore, must be directed to this; for in this he attempts to produce persuasion. Is it not so?
_Phæ._ Yes.
_Socr._ It is clear, therefore, that Thrasymachus, and any one else who seriously endeavours to teach the art of rhetoric, will in the first place describe with all possible accuracy, and make it be seen whether the soul is naturally one and similar, or, like the form of the body, composed of different elements; for this we say is to make known nature.
_Phæ._ Most assuredly.
_Socr._ And, in the second place, in what respect it naturally acts or is acted upon by any thing.
124. _Phæ._ How not?
_Socr._ In the third place, having set in order the different kinds of speech and of soul, and the different manners in which these are affected, he will go through the several causes, adapting each to each, and teaching what kind of soul is necessarily persuaded, and what not persuaded, by particular kinds of speech, and for what reason.
_Phæ._ It will assuredly be best done in this way, as it seems.
_Socr._ Never then, my dear friend, will any thing that is otherwise explained or spoken, be spoken or written by art, either in any other case or in this. But the modern writers on the art of speech-making, whom you yourself have heard, are dissemblers, and conceal the very admirable knowledge they have of the soul. Until, then, they both speak and write according to this method, let us never be persuaded that they write artistically.
_Phæ._ What method is this?
_Socr._ It is not easy to mention the very words themselves; but how it is proper to write, if a man means to be as artistic as he possibly can, I am willing to tell you.
_Phæ._ Tell me then.
125. _Socr._ Since the power of speech is that of leading the soul, it is necessary that he who means to be an orator should know how many kinds of soul there are: but they are so many, and of such and such kinds; whence some men are of this character and some of that character.
These then being thus divided, there are again so many kinds of speech, each of a certain character. Now men of such a character are for this particular reason easily persuaded by certain speeches, and persons of a different character are for these reasons with difficulty persuaded. It is necessary, therefore, that he, after having sufficiently understood all this, when he afterwards perceives these very things taking place in actions, and being done, should be able to follow them rapidly by perception, otherwise he will know nothing more than the very things which he formerly heard from his preceptor. 126. But when he is sufficiently competent to say, what kind of person is persuaded by what kind of speeches, and is able, when he sees him before him, to point out to himself that this is the person and this the nature for which those speeches were formerly made now actually present before me, and to which these particular speeches are to be addressed, in order to persuade him to these particular things,—when he has acquired all this, and has learnt moreover the proper seasons for speaking and being silent, and again has made himself master of the seasonable and unseasonable occasions for brevity, plaintiveness, and vehemence, and all the other several kinds of speech which he has learnt, then his art will be beautifully and perfectly accomplished, but not before. But whoever is deficient in any of these particulars, either in speaking, or teaching, or writing, and yet asserts that he speaks by art, is overcome by the person who will not be persuaded. 127. “What then,” perhaps the writer on rhetoric will say, “does it appear to you, Phædrus and Socrates, that the art of speaking, as it is called, must be obtained in this or some other way?”
_Phæ._ It is impossible, Socrates, that it should be obtained in any other way; though it seems to be a work of no small labour.
_Socr._ You say truly. And on this account we ought to turn over all speeches again and again, and consider whether any easier and shorter way to it can be found, in order that we may not in vain go by a long and rough one, when we might have taken a short and smooth one. If, therefore, you have heard of any thing that will assist us, from Lysias or any one else, endeavour to call it to mind, and tell it me.
_Phæ._ If the endeavour were enough I should be able to do so, but just at present I cannot.
128. _Socr._ Are you willing, then, that I should repeat to you a statement which I heard from persons who take an interest in such matters?
_Phæ._ How not?
_Socr._ It is said, however, Phædrus, to be right to state even the wolf’s case.
_Phæ._ And do you do so.
_Socr._ They say, then, that there is no occasion to treat these matters so solemnly, nor to carry them back so far, by such long windings. For as we said in the beginning of our discussion, there is no need at all for one who wishes to become a competent orator to have any thing to do with the truth respecting actions just or good, or men who are such, either by nature or education. For that in courts of justice no attention whatever is paid to the truth of these things, but only to what is plausible, and that it is probability to which one who wishes to speak by art ought to apply himself. And that sometimes even facts that have actually happened must not be stated, unless they are probable, but probabilities both in accusation and defence: and, in short, that a speaker should pursue the probable, and pay no regard at all to truth.
For that when this method is observed throughout the whole speech, it constitutes the perfection of the art.
129. _Phæ._ You have described the very things, Socrates, which they say who profess to be skilled in speech-making; and I remember that we touched briefly upon this in a former part of our discussion; but this appears to be matter of the utmost consequence to those who study these things.
_Socr._ However you have thoroughly fumbled Tisias himself. Let Tisias then tell us this, whether he means any thing else by the probable than that which accords with the opinion of the multitude.
_Phæ._ What else can it be?
_Socr._ Having made, then, as it seems, this wise and artistic discovery, he has written, that if a weak but brave man should be brought to trial for having knocked down a strong and cowardly one, and for having robbed him of his clothes or any thing else, then that neither of them ought to speak the truth, but the coward should say that he was not knocked down by the brave man alone, and the latter should prove this, that they were alone, and then urge this; “How could a man like me ever attack a man like him?” But the other will not admit his own cowardice, but, in attempting to tell some other falsehood, will perhaps supply his adversary with the means of refuting him. And in other cases, such things as these are said according to art. Is it not so, Phædrus?
130. _Phæ._ How not?
_Socr._ Wonderfully clever seems to have been the inventor of this abstruse art, whether Tisias or whoever else he was, and by whatever name he delights to be called. But, my friend, shall we say to him or not?
_Phæ._ What?
_Socr._ Tisias, long since before your arrival, we happened to say, that this probability of yours derives its influence with the multitude from its resemblance to truth; and we just now concluded that in all cases he knows best how to discover resemblances who is best acquainted with the truth. So that, if you have any thing else to say about the art of speaking, we will listen to you; but if not, we shall hold to the conclusions we have lately come to, that unless a man has reckoned up the different natures of those who will have to hear him, and is able to divide things themselves into species, and to comprehend the several particulars under one general idea, he will never be skilled in the art of speaking so far as it is possible for a man to be so. 131. But this he can never acquire without great labour, which a wise man ought not to bestow for the purpose of speaking and acting amongst men, but that he may be able to speak such things as are acceptable to the gods, and act acceptably to them, to the utmost of his power. For, as wiser men than we say, Tisias, a man of understanding ought not to make it his principal study to gratify his fellow-servants, except by the way, but good masters and of good extraction. If therefore the circuit be long, wonder not; 132. for it is to be undertaken for the sake of great ends, not such as you think. And even these, as our argument proves, if any one is willing, will be best attained by those means.
_Phæ._ This appears to me, Socrates, to be very finely said, if only a man could attain to it.
_Socr._ But when one is attempting noble things, it is surely noble also to suffer whatever it may befal us to suffer.
_Phæ._ Assuredly.
_Socr._ As regards, then, the art and want of art in speaking, let this suffice.
133. _Phæ._ How should it not?
_Socr._ But as regards elegance and inelegance in writing, in what way it may be done well, and in what way inelegantly, remains to be considered. Does it not?
_Phæ._ Yes.
_Socr._ Do you know, then, how you may best please God with regard to speeches, both acting and speaking?
_Phæ._ Not at all. Do you?
_Socr._ I can tell a story I have heard of the ancients, its truth they know. But if we ourselves could discover this, do you think we should any longer pay any regard to the opinions of men?
_Phæ._ Your question is ridiculous; but relate what you say you have heard.
134. _Socr._ I have heard then, that at Naucratis, in Egypt, there was one of the ancient gods of that country, to whom was consecrated the bird, which they call Ibis; but the name of the deity himself was Theuth. That he was the first to invent numbers and arithmetic, and geometry and astronomy, and moreover draughts and dice, and especially letters, at the time when Thamus was king of all Egypt, and dwelt in the great city of the upper region which the Greeks call Egyptian Thebes, but the god they call Ammon; to him Theuth went and shewed him his arts, and told him that they ought to be distributed amongst the rest of the Egyptians. Thamus asked him what was the use of each, and as he explained it, according as he appeared to say well or ill, he either blamed or praised them. 135. Now Thamus is reported to have said many things to Theuth respecting each art, both for and against it, which it would be tedious to relate. But when they came to the letters, “This knowledge, O king,” said Theuth, “will make the Egyptians wiser, and better able to remember; for it has been invented as a medicine for memory and wisdom.” But he replied, “Most ingenious Theuth, one person is able to give birth to art, another to judge of what amount of detriment or advantage it will be to those who are to use it, and now you, as being the father of letters, out of fondness have attributed to them just the contrary effect to that which they will have. For this invention will produce forgetfulness in the minds of those who learn it through the neglect of memory, for that through trusting to writing, they will remember outwardly by means of foreign marks, and not inwardly by means of their own faculties. So that you have not discovered a medicine for memory, but for recollection. And you are providing for your disciples the appearance and not the reality of wisdom. For hearing many things through your means without instruction, they will appear to know a great deal, although they are for the most part ignorant, and will become troublesome associates, through thinking themselves wise instead of being so.”
136. _Phæ._ Socrates, you easily make Egyptian and any other country’s tales you please.
_Socr._ But, my friend, those who dwell in the temple of Dodonæan Jupiter said that the first prophetic words issued from an oak. It was sufficient for the men of those days, seeing they were not wise like you moderns, in their simplicity, to listen to an oak and a stone, if only they spoke the truth: and does it make any difference to you, forsooth, who the speaker is, and to what country he belongs? For you do not consider that only, whether the case is so or otherwise.
_Phæ._ You have very properly reproved me; and the case with regard to letters appears to me just as the Theban says.
137. _Socr._ He therefore, who thinks to leave an art in writing, and again, he who receives it, as if something clear and solid would result from the writing, must be full of simplicity, and in reality ignorant of the prophecy of Ammon, since he thinks that written words are of further value than to remind one who already knows the subject of which the writings treat.
_Phæ._ Most correct.
_Socr._ For writing, indeed, Phædrus, has this inconvenience, and truly resembles painting. For its productions stand out as if they were alive, but, if you ask them any question, they observe a solemn silence. And so it is with written discourses; you would think that they spoke as though they possessed some wisdom, but if you ask them about any thing they say, from a desire to understand it, they give only one and the self-same answer. And when it is once written, every discourse is tossed about every where, equally among those who understand it, and among those whom it in no wise concerns, and it knows not to whom it ought to speak, and to whom not. And when it is ill-treated and unjustly reviled, it always needs its father to help it; for, of itself, it can neither defend nor help itself.
138. _Phæ._ This, too, you have said most correctly.
_Socr._ But what? shall we consider another discourse, this one’s legitimate brother, in what manner it is produced, and how far better and more powerful it naturally is than this?
_Phæ._ What is that, and how do you say it is produced?
_Socr._ That which is written with science in the learner’s soul, which is able to defend itself, and knows before whom it ought to speak and be silent.
_Phæ._ You mean the discourse of a man endued with knowledge that has life and soul, of which the written may be justly called an image.
_Socr._ Assuredly. But tell me this. Would an intelligent husbandman, who has seeds that he cares for and which he wishes to be fruitful, seriously sow them in summer-time in the gardens of Adonis, and rejoice at seeing them growing up beautifully within eight days, or would he do this, if he did it at all, for the sake of sport or pastime; but the seed which he treats seriously, availing himself of the husbandman’s skill and sowing it in its proper soil, would he be content that what he has sown shall come to maturity in the eighth month?
139. _Phæ._ Just so, Socrates, he would do the one seriously, and the other, as you say, for amusement.
_Socr._ But shall we say that he who possesses a knowledge of what is just, beautiful and good, shews less intelligence than a husbandman in the management of his own seeds?
_Phæ._ By no means.
_Socr._ He will not, then, seriously write them in water, sowing them with ink by means of a pen, with words that are unable to defend themselves by speech, and unable adequately to teach the truth.
_Phæ._ In all probability he will not.
_Socr._ Surely not. But, as it seems, he will sow and write, when he does write, in the gardens of letters for the sake of diversion, treasuring up memoranda for himself, when he comes to the forgetfulness of old age, and for all who are going on the same track, and he will be delighted at seeing them in their tender growth, and while other men pursue other diversions, refreshing themselves with banquets, and other pleasures akin to these, he, as it appears, instead of these, will pass his time in the diversions I have mentioned.
140. _Phæ._ You speak of a very noble in comparison of a mean diversion, Socrates, when a man is able to divert himself with discourses, telling stories about justice and the other things you mention.
_Socr._ It is so indeed, my dear Phædrus. But, in my opinion, a far more noble employment results from this, when a man availing himself of dialectic art, on meeting with a congenial soul, plants and sows scientific discourses which are able to aid both themselves and him that planted them, and are not unfruitful but contain seed within themselves, from whence others springing up in other minds are able to make this seed immortal, and make their possessor happy as far as it is possible for man to be so.
_Phæ._ This that you mention is far more noble.
_Socr._ Now then, Phædrus, since this is agreed on, we are able to determine our former questions.
_Phæ._ What are they?
_Socr._ Those which, in our desire to consider them, led us to the present point: namely, that we might examine into the reproach cast on Lysias for writing speeches, and then speeches themselves, which are written by art or without art. Now that which is artistic and that which is not appears to me to have been tolerably well explained.
141. _Phæ._ It appears so. But remind me of it again, in what way.
_Socr._ Before a man knows the truth of each subject on which he speaks or writes, and is able to define the whole of a thing, and when he has defined it again knows how to divide it into species until he comes to the indivisible; and in like manner, having distinguished the nature of the soul, and having found out what kind of speech is adapted to the nature of each, he so disposes and adorns his speech, applying to a soul of varied powers speeches that are various and all-harmonious, and simple ones to a simple soul, before this is done, he will not be able to manage speech with art, as far as it might be done, either for the purpose of teaching or persuading, as the whole of our former argument has proved.
_Phæ._ This is exactly how it appeared.
142. _Socr._ But what as to its being honourable or disgraceful to speak and write speeches, and under what circumstances it may be called a reproach or not, has not what we have said a little before sufficed to prove?
_Phæ._ What was that?
_Socr._ That if either Lysias, or any one else, has ever written, or shall hereafter write, privately or publicly, writing a state document in proposing a law, and thinks that there is in it great stability and clearness, this is a reproach to the writer, whether any one says so or not. For to be utterly ignorant of what is just and unjust, evil and good, cannot be otherwise than truly disgraceful, though the whole mass of mankind should unite in its praise.
143. _Phæ._ Certainly not.
_Socr._ But he who thinks that in a written discourse, on whatever subject, there must necessarily be much that is sportive, and that no discourse, in prose or verse, deserving of much study, has ever been written or spoken, as those declamations used to be spoken without discrimination and instructive method, for the sake of persuasion, but that in truth the best of them were for the purpose of reminding those who already know, but that only in discourses taught and spoken for the sake of instruction, and really written in the soul about things just, and beautiful, and good, there is found what is clear and perfect and worthy of study; and that such discourses ought to be called as it were their author’s legitimate offspring; first of all that which is in himself, if it is there by his own invention, then any children or brothers of the former that have at the same time worthily sprung up in the souls of others; whoever thinks thus and dismisses all others, that man, Phædrus, appears to be such a one as you and I should pray that we might become.
144. _Phæ._ I, for my part, entirely wish and pray for what you mention.
_Socr._ Be we then content with having thus far amused ourselves with the subject of speeches; and do you go and tell Lysias that we, having descended to the fountain of the nymphs, have heard words which charged us to tell Lysias and any one else who composes speeches, and Homer and any one else who is in the habit of composing poetry, epic or lyric[133], and thirdly, Solon and whosoever commits political discourses to writing under the name of laws, if they composed their works knowing how the truth stands, and able to defend them when brought to account for what they have written, and being themselves capable by speaking to shew that their writings are poor, then they ought not to be named from these works, but from those to which they have seriously applied themselves.
----- Footnote 133: Ψιλὴν ἢ ἐν ᾠδῇ, without music or with.
----- 145. _Phæ._ What name, then, do you assign them?
_Socr._ To call them wise, Phædrus, appears to me to be a great matter, and proper for God alone; but lovers of wisdom, or some such name, would suit them better, and be in better taste.
_Phæ._ And it would be nothing out of the way.
_Socr._ Him, therefore, who has nothing more valuable than what he has written, by turning it upwards and downwards for a long time, patching and clipping it bit by bit, may you not justly designate a poet, or a compiler of speeches, or a writer of laws?
_Phæ._ How not?
_Socr._ Tell this, then, to your friend.
_Phæ._ But you? what will you do? For we must not pass over your friend.
_Socr._ Whom do you mean?
146. _Phæ._ The beautiful Isocrates. What news will you take him, Socrates? what shall we say he is?
_Socr._ Isocrates is still young, Phædrus; but what I prophesy of him I am willing to say.
_Phæ._ What?
_Socr._ He appears to me to have better natural endowments than to be compared with the speeches of Lysias, and moreover to be endued with a nobler disposition, so that it would not be at all wonderful if, as he advances in age, he should in this very pursuit of speech-making, to which he is now applying himself, surpass all who have ever attempted speeches, as if they were boys, and besides, if he should not be content with this, that a more divine impulse may lead him to greater things; for, my friend, there is a natural love of wisdom in the mind of the man. This message, then, I will take from the gods of this spot to Isocrates my favourite, and do you take the other to Lysias as yours.
147. _Phæ._ This shall be done. But let us depart, since the heat has become less oppressive.
_Socr._ Ought we not to go after we have prayed to these gods?
_Phæ._ How not?
_Socr._ O beloved Pan, and all ye other gods of this place, grant me to become beautiful in the inner man, and that whatever outward things I have may be at peace with those within. May I deem the wise man rich, and may I have such a portion of gold as none but a prudent man can either bear or employ.
Do we need any thing else, Phædrus? for myself I have prayed enough.
_Phæ._ Make the same prayer for me, too; for the possessions of friends are common.
_Socr._ Let us depart.
INTRODUCTION TO THE THEÆTETUS.
Theodorus, a famous geometrician of Cyrene and a follower of Protagoras, is represented to have met Socrates at Athens, and to have been asked by him whether among his pupils there were any who promised to become eminent. Theodorus particularizes one above all the rest, who, while he is speaking, is seen approaching. His name is Theætetus. Socrates, having heard him so highly spoken of by Theodorus, at once opens upon the subject which he wishes to discuss, and asks What science is.
Theætetus, in answer, enumerates several particular sciences, but is soon led to understand that the question is not, how many sciences there are, but what science itself is; and by an instance in point shews that he does so. Still he doubts his own ability to answer the question proposed, but is at length induced to make the attempt by Socrates pleasantly describing himself as inheriting his own mother’s skill in midwifery, by which he is able to bring to the birth and deliver the mental conceptions of those whose souls are pregnant with ideas[134].
----- Theætetus, then, first of all says that science is nothing else than perception. This, Socrates observes, is the opinion of Protagoras, differently expressed; for he said, that man is the measure of all things, in other words that all things are such as they appear to each person. In order to examine the truth of this doctrine Socrates begins by stating it more fully. Protagoras asserts that nothing exists of itself, nor can any thing be designated by any quality, for what we call great will, in reference to something else, be also small, and what we call heavy, light, and so on, so that nothing ever exists but is always becoming. Consequently all things spring from motion, and the relation that they bear to each other. Thus, with respect to colour, it does not actually exist, it is neither in the object seen nor in the eye itself, but results from the application of the eye to the object, and so is the intermediate production of both. Again if you compare six with four they appear to be half as many again, but if with twelve, only the half, whence it appears that the same number is at one time great, at another small, which would not be the case if numbers had a fixed and determined magnitude. The principle then on which all things depend is this, That the universe is nothing but motion, of which there are two species, the one active, the other passive, by the union of which that which is perceivable and perception itself consist. Thus when the eye and a corresponding object, meeting together, produce whiteness and its connate perception, the eye sees, and becomes not vision, but a seeing eye, and the object itself becomes not whiteness but white: so that nothing is essentially one, but is always being produced by something else, and therefore the word “being” must be entirely done away with.
But here it may be objected that the perceptions produced in persons who dream, or are diseased or mad, are utterly false, and so far are the things that appear to them from existing, that none of them have any real existence at all; how then can it be said that perception is science, and that things which appear to every one are to that person what they appear to be? The answer is, that the things which appear are most certainly true to the percipient; just as if wine appears bitter to a sick person, to him it is certainly bitter; and again with regard to dreams, there is no certain way of distinguishing a state of being awake from dreaming; and as the object perceived and the percipient exist or are produced by relation to each other, neither exists or is produced of itself, but the object perceived does exist in relation to the percipient and to him is true, so that he has a scientific knowledge of what he perceives[135].
----- Socrates then proposes to examine the correctness of Protagoras’s theory. If what he says is true, a pig or any other creature that possesses perception will be the measure of all things, as well as a man, and man himself will be equal in wisdom to the gods. To which Protagoras is supposed to answer, that the gods are not to be brought into the question at all, for that it does not appear whether they exist or not; and as to brute creatures, it would be strange if every man did not excel them in wisdom, and besides no argument deduced from them can be conclusive but rests only on probability, which cannot be allowed in a discussion respecting science. Well then, when we hear barbarians speak, whose language we have not learnt, are we to say that we both hear and know what they say? to which the answer is, that we both hear and know the sounds, but not the meaning of the words. Again it is objected, if perception is science, a person may remember a thing and not know it, for instance he may obtain a knowledge of a thing by seeing it, and then shut his eyes, in that case he remembers it, but does not see it, but inasmuch as sight is perception and perception knowledge, he cannot know it, because he does not see it, and yet he remembers it; which is absurd. But Protagoras will not admit this conclusion, but will say that memory is very different from perception, and that the things which we appear to remember are not the same as those that we formerly perceived. Still, though all things are as they appear to each person, it must be admitted that there is such a thing as wisdom and a wise man, and he is wise who changes the aspect of objects to another, and causes things that appear and are evil to any one, to appear and be good; just as a physician by means of medicine changes the habit of the body from bad to good[136].
----- Thus far Socrates had carried on the discussion with Theætetus, adducing the answers which Protagoras himself would have given to the objections brought against his theory, but expressing no opinion of his own. He now persuades Theodorus to advocate the cause of Protagoras, and himself undertakes to refute it. Protagoras, then, maintains that what appears to each person exists to him to whom it appears; now all men think themselves in some respects wiser than others, and others wiser than themselves, so that all admit that there is wisdom and ignorance among themselves. Now is not wisdom true opinion, and ignorance false opinion?
If so, some men form false opinions, and yet that could not be if man is the measure of all things. Again, according to his doctrine, the same thing will be both true and false; for instance, Protagoras’s own theory will be true to himself, but false to all who do not agree with him, and by how many more they are to whom it does not appear to be true than those to whom it does so appear, by so much the more it is not than it is: and so in admitting that the opinion of those who differ from him is true he admits that his own opinion is false. Moreover, in political matters Protagoras will admit that things honourable and base, just and unjust, are such to each city as each city considers them; but he will allow that one counsellor excels another, and that all laws are not equally expedient, though the city that enacts them thinks them so[137].
----- The mention of political matters leads Socrates to interrupt the course of the argument, and to contrast the life of a politician with that of a philosopher, in which he shews how far more exalted are the views of the latter than of the former. The digression, however, has this connexion with the subject in hand, that it exposes the utter worthlessness of political expediency, which depends on appearances only, and vindicates the aspirations of philosophers, who devote themselves to the contemplation of wisdom and true virtue[138].
----- To return, then, to the original subject. Those who maintain that whatever appears to each person exists to him to whom it appears, persist that what a city enacts as appearing just to itself is just to that city as long as it continues in force; but in enacting laws the real object is to make them as advantageous to itself as possible, but what is advantageous regards also the future, for laws are enacted that they may be advantageous for the future. But if man is the measure of all things, he must also contain within himself the criterion of things about to happen; yet it will be admitted, in a variety of instances that are adduced, that a person who is skilled is better able to judge of the future than one who is unskilled: and Protagoras himself can judge beforehand better than any private person what arguments are likely to be available in a court of justice, so that not every man, but the wise man only, is the true measure of things[139].
----- This part of the argument being brought to a close, Socrates next proposes to consider the essence that is said to consist in motion, a doctrine which the followers of Heraclitus were then advocating very strenuously. Now there are two species of motion, removal and change; the former is when a thing passes from one place to another, the latter a change of quality, as when a thing becomes black from white, or hard from soft; and all things must undergo both kinds of motion, otherwise the same thing would be both in motion and at rest at the same time, and in that case it would not be more correct to say that all things are in motion than that they are at rest. Since then every thing must be continually undergoing a process of change at the same time that it is in motion, there can be nothing fixed and certain, so that perception cannot be science, for, as all things are in motion; perception itself, which results from the relation between the object and the percipient, must be in a constant state of motion and change[140].
----- Theætetus now resumes the argument, and though it would seem that Protagoras’s doctrine had been already sufficiently refuted, yet Socrates resolves to try it by one more test. Each sense has its peculiar perception, and such things as are perceived by one faculty cannot be perceived by another; for instance, what is perceived by hearing cannot be perceived by sight, and what is perceived by sight cannot be perceived by hearing; yet we can form a notion of them both together, and observe what properties they have in common, and how they differ: this, however, is not done by the senses, but by the soul itself, for children as soon as they are born are able to perceive by the bodily organs, but only arrive, with much labour and difficulty, at the power of comparing things with each other, and so obtain a knowledge of them, whence again it follows that perception and science are not the same[141].
----- The first definition of science attempted by Theætetus being thus overthrown, Socrates again asks him, What science is. To which he answers that it appears to be true judgment. Socrates however thinks proper first to enquire whether there is such a thing as false judgment.
People, he says, must either know or not know things about which they form judgments. Now false judgments are formed, when a person thinks