Stranger: And two of these are, as we affirm, incapable of communion with one another.
Theaetetus: Quite incapable.
Stranger: Whereas being surely has communion with both of them, for both of them are?
Theaetetus: Of course.
Stranger: That makes up three of them.
Theaetetus: To be sure.
Stranger: And each of them is other than the remaining two, but the same with itself.
Theaetetus: True.
Stranger: But then, what is the meaning of these two words, “same” and “other”? Are they two new kinds other than the three, and yet always of necessity intermingling with them, and are we to have five kinds instead of three; or when we speak of the same and other, are we unconsciously speaking of one of the three first kinds?
Theaetetus: Very likely we are.
Stranger: But, surely, motion and rest are neither the other nor the same.
Theaetetus: How is that?
Stranger: Whatever we attribute to motion and rest in common, cannot be either of them.
Theaetetus: Why not?
Stranger: Because motion would be at rest and rest in motion, for either of them, being predicated of both, will compel the other to change into the opposite of its own nature, because partaking of its opposite.
Theaetetus: Quite true.
Stranger: Yet they surely both partake of the same and of the other?
Theaetetus: Yes.
Stranger: Then we must not assert that motion, any more than rest, is either the same or the other.
Theaetetus: No; we must not.
Stranger: But are we to conceive that being and the same are identical?
Theaetetus: Possibly.
Stranger: But if they are identical, then again in saying that motion and rest have being, we should also be saying that they are the same.
Theaetetus: Which surely cannot be.
Stranger: Then being and the same cannot be one.