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 voyage. You would not be inclined to say, would you, that navigation 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 say 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 advantage 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. But does he therefore confer no benefit when he works for nothing? Certainly, he confers a benefit. Then now, Thrasymachus, there is no longer any doubt that neither arts nor governments provide for their own interests; but, as we were before saying, they rule and provide for the interests of their subjects who are the weaker and not the stronger --to their good they attend and not to the good of the superior. And this is the reason, my dear Thrasymachus, why, as I was just now say...
