SOCRATES: Let us assume these two principles, and also a third, which is compounded out of them; but I fear that I am ridiculously clumsy at these processes of division and enumeration.
PROTARCHUS: What do you mean, my good friend?
SOCRATES: I say that a fourth class is still wanted.
PROTARCHUS: What will that be?
SOCRATES: Find the cause of the third or compound, and add this as a fourth class to the three others.
PROTARCHUS: And would you like to have a fifth class or cause of resolution as well as a cause of composition?
SOCRATES: Not, I think, at present; but if I want a fifth at some future time you shall allow me to have it.
PROTARCHUS: Certainly.
SOCRATES: Let us begin with the first three; and as we find two out of the three greatly divided and dispersed, let us endeavour to reunite them, and see how in each of them there is a one and many.
PROTARCHUS: If you would explain to me a little more about them, perhaps I might be able to follow you.