Plato on the Movement toward Knowledge and the Limitations of Writing: from The Seventh Letter

For everything that exists there are three instruments by which the knowledge of it is necessarily imparted; fourth, there is the knowledge itself, and, as fifth, we must count the thing itself which is known and truly exists. The first is the name, the, second the definition, the third. the image, and the fourth the knowledge. If you wish to learn what I mean, take these in the case of one instance, and so understand them in the case of all. A circle is a thing spoken of, and its name is that very word which we have just uttered. The second thing belonging to it is its definition, made up names and verbal forms. For that which has the name "round," "annular," or, "circle," might be defined as that which has the distance from its circumference to its centre everywhere equal. Third, comes that which is drawn and rubbed out again, or turned on a lathe and broken up-none of which things can happen to the circle itself-to which the other things, mentioned have reference; for it is something of a different order from them. Fourth, comes knowledge, intelligence and right opinion about these things. Under this one head we must group everything which has its existence, not in words nor in bodily shapes, but in souls-from which it is dear that it is something different from the nature of the circle itself and from the three things mentioned before. Of these things intelligence comes closest in kinship and likeness to the fifth, and the others are farther distant. 

The same applies to straight as well as to circular form, to colours, to the good, the, beautiful, the just, to all bodies whether manufactured or coming into being in the course of nature, to fire, water, and all such things, to every living being, to character in souls, and to all things done and suffered. For in the case of all these, no one, if he has not some how or other got hold of the four things first mentioned, can ever be completely a partaker of knowledge of the fifth. Further, on account of the weakness of language, these (i.e., the four) attempt to show what each thing is like, not less than what each thing is. For this reason no man of intelligence will venture to express his philosophical views in language, especially not in language that is unchangeable, which is true of that which is set down in written characters. 

Again you must learn the point which comes next. Every circle, of those which are by the act of man drawn or even turned on a lathe, is full of that which is opposite to the fifth thing. For everywhere it has contact with the straight. But the circle itself, we say, has nothing in either smaller or greater, of that which is its opposite. We say also that the name is not a thing of permanence for any of them, and that nothing prevents the things now called round from being called straight, and the straight things round; for those who make changes and call things by opposite names, nothing will be less permanent (than a name). Again with regard to the definition, if it is made up of names and verbal forms, the sameremark holds that there is no sufficiently durable permanence in it. And there is no end to the instances of the ambiguity from which each of the four suffers; but the greatest of them is that which we mentioned a little earlier, that, whereas there are two things, that which has real being, and that which is only a quality, when the soul is seeking to know, not the quality, but the essence, each of the four, presenting to the soul by word and in act that which it is not seeking (i.e., the quality), a thing open to refutation by the senses, being merely the thing presented to the soul in each particular case whether by statement or the act of showing, fills, one may say, every man with puzzlement and perplexity. 

Now in subjects in which, by reason of our defective education, we have not been accustomed even to search for the truth, but are satisfied with whatever images are presented to us, we are not held up to ridicule by one another, the questioned by questioners, who can pull to pieces and criticise the four things. But in subjects where we try to compel a man to give a clear answer about the fifth, any one of those who are capable of overthrowing an antagonist gets the better of us, and makes the man, who gives an exposition in speech or writing or in replies to questions, appear to most of his hearers to know nothing of the things on which he is attempting to write or speak; for they are sometimes not aware that it is not the mind of the writer or speaker which is proved to be at fault, but the defective nature of each of the four instruments. The process however of dealing with all of these, as the mind moves up and down to each in turn, does after much effort give birth in a well-constituted mind to knowledge of that which is well constituted. But if a man is ill-constituted by nature (as the state of the soul is naturally in the majority both in its capacity for learning and in what is called moral character)-or it may have become so by deterioration-not even Lynceus could endow such men with the power of sight. 

In one word, the man who has no natural kinship with this matter cannot be made akin to it by quickness of learning or memory; for it cannot be engendered at all in natures which are foreign to it. Therefore, if men are not by nature kinship allied to justice and all other things that are honourable, though they may be good at learning and remembering other knowledge of various kinds-or if they have the kinship but are slow learners and have no memory-none of all these will ever learn to the full the truth about virtue and vice. For both must be learnt together; and together also must be learnt, by complete and long continued study, as I said at the beginning, the true and the false about all that has real being. Aftermuch effort, as names, definitions, sights, and other data of sense, are brought into contact and friction one with another, in the course of scrutiny and kindly testing by men who proceed by question and answer without ill will, with a sudden flash there shines forth understanding about every problem, and an intelligence whose efforts reach the furthest limits of human powers. Therefore every man of worth, when dealing with matters of worth, will be far from exposing them to ill feeling and misunderstanding among men by committing them to writing. In one word, then, it may be known from this that, if one sees written treatises composed by anyone, either the laws of a lawgiver, or in any other form whatever, these are not for that man the things of most worth, if he is a man of worth, but that his treasures are laid up in the fairest spot that he possesses. But if these things were worked at by him as things of real worth, and committed to writing, then surely, not gods, but men "have themselves bereft him of his wits."