Cleinias:  What do you mean?

Athenian:  I mean this:  when one thing changes another, and that another, of such will there be any primary changing element?  How can a thing which is moved by another ever be the beginning of change?  Impossible.  But when the self-moved changes other, and that again other, and thus thousands upon tens of thousands of bodies are set in motion, must not the beginning of all this motion be the change of the self-moving principle?

Cleinias:  Very true, and I quite agree.

Athenian:  Or, to put the question in another way, making answer to ourselves:  If, as most of these philosophers have the audacity to affirm, all things were at rest in one mass, which of the above-mentioned principles of motion would first spring up among them?

Cleinias:  Clearly the self-moving; for there could be no change in them arising out of any external cause; the change must first take place in themselves.

Athenian:  Then we must say that self-motion being the origin of all motions, and the first which arises among things at rest as well as among things in motion, is the eldest and mightiest principle of change, and that which is changed by another and yet moves other is second.

Cleinias:  Quite true.

Athenian:  At this stage of the argument let us put a question.

Cleinias:  What question?

Athenian:  If we were to see this power existing in any earthy, watery, or fiery substance, simple or compound—­how should we describe it?

Cleinias:  You mean to ask whether we should call such a self-moving power life?

Athenian:  I do.

Cleinias:  Certainly we should.

Athenian:  And when we see soul in anything, must we not do the same—­must we not admit that this is life?

Cleinias:  We must.

Athenian:  And now, I beseech you, reflect—­you would admit that we have a threefold knowledge of things?

Cleinias:  What do you mean?

Athenian:  I mean that we know the essence, and that we know the definition of the essence, and the name—­these are the three; and there are two questions which may be raised about anything.

Cleinias:  How two?

Athenian:  Sometimes a person may give the name and ask the definition; or he may give the definition and ask the name.  I may illustrate what I mean in this way.

Cleinias:  How?

Athenian:  Number like some other things is capable of being divided into equal parts; when thus divided, number is named ‘even,’ and the definition of the name ‘even’ is ‘number divisible into two equal parts’?

Cleinias:  True.

Athenian:  I mean, that when we are asked about the definition and give the name, or when we are asked about the name and give the definition—­in either case, whether we give name or definition, we speak of the same thing, calling ‘even’ the number which is divided into two equal parts.