Ion: The charioteer, clearly.
Socrates: And will the reason be that this is his art, or will there be any other reason?
Ion: No, that will be the reason.
Socrates: And every art is appointed by God to have knowledge of a certain work; for that which we know by the art of the pilot we do not know by the art of medicine?
Ion: Certainly not.
Socrates: Nor do we know by the art of the carpenter that which we know by the art of medicine?
Ion: Certainly not.
Socrates: And this is true of all the arts;—that which we know with one art we do not know with the other? But let me ask a prior question: You admit that there are differences of arts?
Ion: Yes.
Socrates: You would argue, as I should, that when one art is of one kind of knowledge and another of another, they are different?
Ion: Yes.
Socrates: Yes, surely; for if the subject of knowledge were the same, there would be no meaning in saying that the arts were different—if they both gave the same knowledge. For example, I know that here are five fingers, and you know the same. And if I were to ask whether I and you became acquainted with this fact by the help of the same art of arithmetic, you would acknowledge that we did?
Ion: Yes.
Socrates: Tell me, then, what I was intending to ask you—whether this holds universally? Must the same art have the same subject of knowledge, and different arts other subjects of knowledge?
Ion: That is my opinion, Socrates.
Socrates: Then he who has no knowledge of a particular art will have no right judgment of the sayings and doings of that art?
Ion: Very true.
Socrates: Then which will be a better judge of the lines which you were reciting from Homer, you or the charioteer?
Ion: The charioteer.
Socrates: Why, yes, because you are a rhapsode and not a charioteer.
Ion: Yes.
Socrates: And the art of the rhapsode is different from that of the charioteer?
Ion: Yes.
Socrates: And if a different knowledge, then a knowledge of different matters?
Ion: True.