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another, or goes round in the same place, is not that what is called
Theod. Yes.
Soc. Here then we have one kind of motion. But when a thing,
remaining on the same spot, grows old, or becomes black from being
white, or hard from being soft, or undergoes any other change, may not
this be properly called motion of another kind?
Theod. I think so.
Soc. Say rather that it must be so. Of motion then there are these
two kinds, "change," and "motion in place."
Theod. You are right.
Soc. And now, having made this distinction, let us address ourselves
to those who say that all is motion, and ask them whether all things
according to them have the two kinds of motion, and are changed as
well as move in place, or is one thing moved in both ways, and another
in one only?
Theod. Indeed, I do not know what to answer; but I think they
would say that all things are moved in both ways.
Soc. Yes, comrade; for, if not, they would have to say that the same
things are in motion and at rest, and there would be no more truth
in saying that all things are in motion, than that all things are at
Theod. To be sure.
Soc. And if they are to be in motion, and nothing is to be devoid of
motion, all things must always have every sort of motion?
Theod. Most true.
Soc. Consider a further point: did we not understand them to explain
the generation of heat, whiteness, or anything else, in some such
manner as the following:-were they not saying that each of them is
moving between the agent and the patient, together with a
perception, and that the patient ceases to be a perceiving power and
becomes a percipient, and the agent a quale instead of a quality? I
suspect that quality may appear a strange and uncouth term to you, and
that you do not understand the abstract expression. Then I will take
concrete instances: I mean to say that the producing power or agent
becomes neither heat nor whiteness but hot and white, and the like
of other things. For I must repeat what I said before, that neither
the agent nor patient have any absolute existence, but when they
come together and generate sensations and their objects, the one
becomes a thing a certain quality, and the other a percipient. You
Theod. Of course.
Soc. We may leave the details of their theory unexamined, but we
must not forget to ask them the only question with which we are
concerned: Are all things in motion and flux?
Theod. Yes, they will reply.
Soc. And they are moved in both those ways which we distinguished,
that is to Way, they move in place and are also changed?
Theod. Of course, if the motion is to be perfect.
Soc. If they only moved in place and were not changed, we should
be able to say what is the nature of the things which are in motion
and flux.
Theod. Exactly.
Soc. But now, since not even white continues to flow white, and
whiteness itself is a flux or change which is passing into another
colour, and is never to be caught standing still, can the name of
any colour be rightly used at all?
Theod. How is that possible, Socrates, either in the case of this or
of any other quality-if while we are using the word the object is
escaping in the flux?
Soc. And what would you say of perceptions, such as sight and
hearing, or any other kind of perception? Is there any stopping in the
act of seeing and hearing?
Theod. Certainly not, if all things are in motion.

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