e to give an
account of themselves. They admit the existence of a mortal living
creature, which is a body containing a soul, and to this they would not
refuse to attribute qualities--wisdom, folly, justice and injustice. The
soul, as they say, has a kind of body, but they do not like to assert
of these qualities of the soul, either that they are corporeal, or that
they have no existence; at this point they begin to make distinctions.
'Sons of earth,' we say to them, 'if both visible and invisible
qualities exist, what is the common nature which is attributed to them
by the term "being" or "existence"?' And, as they are incapable of
answering this question, we may as well reply for them, that being is
the power of doing or suffering. Then we turn to the friends of ideas:
to them we say, 'You distinguish becoming from being?' 'Yes,' they will
reply. 'And in becoming you participate through the bodily senses, and
in being, by thought and the mind?' 'Yes.' And you mean by the word
'participation' a power of doing or suffering? To this they answer--I
am acquainted with them, Theaetetus, and know their ways better than you
do--that being can neither do nor suffer, though becoming may. And we
rejoin: Does not the soul know? And is not 'being' known? And are not
'knowing' and 'being known' active and passive? That which is known is
affected by knowledge, and therefore is in motion. And, indeed, how
can we imagine that perfect being is a mere everlasting form, devoid of
motion and soul? for there can be no thought without soul, nor can soul
be devoid of motion. But neither can thought or mind be devoid of some
principle of rest or stability. And as children say entreatingly,
'Give us both,' so the philosopher must include both the moveable and
immoveable in his idea of being. And yet, alas! he and we are in the
same difficulty with which we reproached the dualists; for motion and
rest are contradictions--how then can they both exist? Does he who
affirms this mean to say that motion is rest, or rest motion? 'No; he
means to assert the existence of some third thing, different from them
both, which neither rests nor moves.' But how can there be anything
which neither rests nor moves? Here is a second difficulty about being,
quite as great as that about not-being. And we may hope that any light
which is thrown upon the one may extend to the other.

Leaving them for the present, let us enquire what we mean by giving many
names to the