STRANGER: There are many accomplished men, Socrates, who say, believing themselves to speak wisely, that the art of measurement is universal, and has to do with all things. And this means what we are now saying; for all things which come within the province of art do certainly in some sense partake of measure. But these persons, because they are not accustomed to distinguish classes according to real forms, jumble together two widely different things, relation to one another, and to a standard, under the idea that they are the same, and also fall into the converse error of dividing other things not according to their real parts. Whereas the right way is, if a man has first seen the unity of things, to go on with the enquiry and not desist until he has found all the differences contained in it which form distinct classes; nor again should he be able to rest contented with the manifold diversities which are seen in a multitude of things until he has comprehended all of them that have any affinity within the bounds of one similarity and embraced them within the reality of a single kind. But we have said enough on this head, and also of excess and defect; we have only to bear in mind that two divisions of the art of measurement have been discovered which are concerned with them, and not forget what they are. YOUNG SOCRATES: We will not forget. STRANGER: And now that this discussion is completed, let us go on to consider another question, which concerns not this argument only but the conduct of such arguments in general. YOUNG SOCRATES: What is this new question? STRANGER: Take the case of a child who is engaged in learning his letters: when he is asked what letters make up a word, should we say that the question is intended to improve his grammatical knowledge of that particular word, or of all words? YOUNG SOCRATES: Clearly, in order that he may have a better knowledge of all words. STRANGER: And is our enquiry about the Statesman intended only to improve our knowledge of politics, or our power of reasoning generally? YOUNG SOCRATES: Clearly, as in the former example, the purpose is general. STRANGER: Still less would any rational man seek to analyse the notion of weaving for its own sake. But people seem to forget that some things have sensible images, which are readily known, and can be easily pointed out when any one desires to answer an enquirer without any trouble or argument; whereas the greatest and highest truths have no outward image of themselves visible to man, which he who wishes to satisfy the soul of the enquirer can adapt to the eye of sense (compare Phaedr.), and therefore we ought to train ourselves to give and accept a rational account of them; for immaterial things, which are the noblest and greatest, are shown only in thought and idea, and in no other way, and all that we are now saying is said for the sake of them. Moreover, there is always less difficulty in fixing the mind on small matters than on great.