ion that some classes
mingle with one another, and others not.

STRANGER: That such a communion of kinds is according to nature, we had
already proved before we arrived at this part of our discussion.

THEAETETUS: Certainly.

STRANGER: Let us proceed, then. May we not say that motion is other than
the other, having been also proved by us to be other than the same and
other than rest?

THEAETETUS: That is certain.

STRANGER: Then, according to this view, motion is other and also not
other?

THEAETETUS: True.

STRANGER: What is the next step? Shall we say that motion is other than
the three and not other than the fourth,--for we agreed that there
are five classes about and in the sphere of which we proposed to make
enquiry?

THEAETETUS: Surely we cannot admit that the number is less than it
appeared to be just now.

STRANGER: Then we may without fear contend that motion is other than
being?

THEAETETUS: Without the least fear.

STRANGER: The plain result is that motion, since it partakes of being,
really is and also is not?

THEAETETUS: Nothing can be plainer.

STRANGER: Then not-being necessarily exists in the case of motion and of
every class; for the nature of the other entering into them all, makes
each of them other than being, and so non-existent; and therefore of all
of them, in like manner, we may truly say that they are not; and again,
inasmuch as they partake of being, that they are and are existent.

THEAETETUS: So we may assume.

STRANGER: Every class, then, has plurality of being and infinity of
not-being.

THEAETETUS: So we must infer.

STRANGER: And being itself may be said to be other than the other kinds.

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 any one
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