hem; they are always
carrying about with them an adversary, like the wonderful ventriloquist,
Eurycles, who out of their own bellies audibly contradicts them.

THEAETETUS: Precisely so; a very true and exact illustration.

STRANGER: And now, if we suppose that all things have the power of
communion with one another--what will follow?

THEAETETUS: Even I can solve that riddle.

STRANGER: How?

THEAETETUS: Why, because motion itself would be at rest, and rest again
in motion, if they could be attributed to one another.

STRANGER: But this is utterly impossible.

THEAETETUS: Of course.

STRANGER: Then only the third hypothesis remains.

THEAETETUS: True.

STRANGER: For, surely, either all things have communion with all; or
nothing with any other thing; or some things communicate with some
things and others not.

THEAETETUS: Certainly.

STRANGER: And two out of these three suppositions have been found to be
impossible.

THEAETETUS: Yes.

STRANGER: Every one then, who desires to answer truly, will adopt the
third and remaining hypothesis of the communion of some with some.

THEAETETUS: Quite true.

STRANGER: This communion of some with some may be illustrated by the
case of letters; for some letters do not fit each other, while others
do.

THEAETETUS: Of course.

STRANGER: And the vowels, especially, are a sort of bond which pervades
all the other letters, so that without a vowel one consonant cannot be
joined to another.

THEAETETUS: True.

STRANGER: But does every one know what letters will unite with what? Or
is art required in order to do so?

THEAETETUS: Art is required.

STRANGER: What art?

THEAETETUS: The art of grammar.

STRANGER: And is not this also true of sounds high and low?--Is not he
who has the art to know what sounds mingle, a musician, and he who is
ignorant, not a musician?

THEAETETUS: Yes.

STRANGER: And we shall find this to be generally true of art or the
absence of art.

THEAETETUS: Of course.

STRANGER: And as classes are admitted by us in like manner to be some of
them capable and others incapable of intermixture, must not he who would
rightly show what kinds will unite and what will not, proceed by the
help of science in the path of argument? And will he not ask if the
connecting links are universal, and so capable of intermixture with all
things; and again, in divisions, whether there are not other universal
classes, which make them possible?

THEAETETUS