Theaetetus: Certainly.
Stranger: Then we may infer that being is not, in respect of as many other things as there are; for not-being these it is itself one, and is not the other things, which are infinite in number.
Theaetetus: That is not far from the truth.
Stranger: And we must not quarrel with this result, since it is of the nature of classes to have communion with one another; and if anyone denies our present statement [viz., that being is not, etc.], let him first argue with our former conclusion [i.e., respecting the communion of ideas], and then he may proceed to argue with what follows.
Theaetetus: Nothing can be fairer.
Stranger: Let me ask you to consider a further question.
Theaetetus: What question?
Stranger: When we speak of not-being, we speak, I suppose, not of something opposed to being, but only different.
Theaetetus: What do you mean?
Stranger: When we speak of something as not great, does the expression seem to you to imply what is little any more than what is equal?
Theaetetus: Certainly not.
Stranger: The negative particles, ou and me, when prefixed to words, do not imply opposition, but only difference from the words, or more correctly from the things represented by the words, which follow them.
Theaetetus: Quite true.
Stranger: There is another point to be considered, if you do not object.
Theaetetus: What is it?
Stranger: The nature of the other appears to me to be divided into fractions like knowledge.
Theaetetus: How so?
Stranger: Knowledge, like the other, is one; and yet the various parts of knowledge have each of them their own particular name, and hence there are many arts and kinds of knowledge.
Theaetetus: Quite true.
Stranger: And is not the case the same with the parts of the other, which is also one?
Theaetetus: Very likely; but will you tell me how?
Stranger: There is some part of the other which is opposed to the beautiful?
Theaetetus: There is.
Stranger: Shall we say that this has or has not a name?
Theaetetus: It has; for whatever we call not-beautiful is other than the beautiful, not than something else.