SOCRATES: And may not the same be said of madness and other disorders? the
difference is only that the times are not equal.

THEAETETUS: Certainly.

SOCRATES: And is truth or falsehood to be determined by duration of time?

THEAETETUS: That would be in many ways ridiculous.

SOCRATES: But can you certainly determine by any other means which of
these opinions is true?

THEAETETUS: I do not think that I can.

SOCRATES: Listen, then, to a statement of the other side of the argument,
which is made by the champions of appearance. They would say, as I
imagine--Can that which is wholly other than something, have the same
quality as that from which it differs? and observe, Theaetetus, that the
word 'other' means not 'partially,' but 'wholly other.'

THEAETETUS: Certainly, putting the question as you do, that which is
wholly other cannot either potentially or in any other way be the same.

SOCRATES: And must therefore be admitted to be unlike?

THEAETETUS: True.

SOCRATES: If, then, anything happens to become like or unlike itself or
another, when it becomes like we call it the same--when unlike, other?