[Thrasymachus] And how am I to convince you, he said, if you are not already convinced by what I have just said; what more can I do for you? Would you have me put the proof bodily into your souls?

Heaven forbid! I said; I would only ask you to be consistent; or, if you change, change openly and let there be no deception. For I must remark, Thrasymachus, if you will recall what was previously said, that although you began by defining the true physician in an exact sense, you did not observe a like exact- ness when speaking of the shepherd; you thought that the shepherd as a shepherd tends the sheep not with a view to their own good, but like a mere diner or banqueter with a view to the pleasures of the table; or, again, as a trader for sale in the market, and not as a shepherd. Yet surely the art of the shep- herd is concerned only with the good of his subjects; he has only to provide the best for them, since the perfection of the art is already insured whenever all the requirements of it are satis- fied. And that was what I was saying just now about the ruler. I conceived that the art of the ruler, considered as a ruler, whether in a State or in private life, could only regard the good of his flock or subjects; whereas you seem to think that the rulers in States, that is to say, the true rulers, like being in authority.

Think! Nay, I am sure of it.

Then why in the case of lesser offices do men never take them willingly without payment, unless under the idea that they govern for the advantage not of themselves but of others? Let me ask you a question: Are not the several arts different, by reason of their each having a separate function? And, my dear illustrious friend, do say what you think, that we may make a little progress.

Yes, that is the difference, he replied.

And each art gives us a particular good and not merely a general one--medicine, for example, gives us health; naviga- tion, safety at sea, and so on?

Yes, he said.

And the art of payment has the special function of giving pay: but we do not confuse this with other arts, any more than the art of the pilot is to be confused with the art of medicine, because the health of the pilot may be improved by a sea voy- age. You would not be inclined to say, would you? that navi- gation is the art of medicine, at least if we are to adopt your exact use of language?

Certainly not.

Or because a man is in good health when he receives pay you would not say that the art of payment is medicine?

I should not.

Nor would you say that medicine is the art of receiving pay because a man takes fees when he is engaged in healing?

Certainly not.

And we have admitted, I said, that the good of each art is specially confined to the art?

Yes.

Then, if there be any good which all artists have in common, that is to be attributed to something of which they all have the common use?

True, he replied.

And when the artist is benefited by receiving pay the ad- vantage is gained by an additional use of the art of pay, which is not the art professed by him?

He gave a reluctant assent to this.

Then the pay is not derived by the several artists from their respective arts. But the truth is, that while the art of medicine gives health, and the art of the builder builds a house, another art attends them which is the art of pay. The various arts may be doing their own business and benefiting that over which they preside, but would the artist receive any benefit from his art unless he were paid as well?

I suppose not.