XV. "According to this reasoning," says my opponent, "you would say that you owe nothing to a physician beyond his paltry fee, nor to your teacher, because you have paid him some money; yet these persons are all held very dear, and are very much respected." In answer to this I should urge that some things are of greater value than the price which we pay for them. You buy of a physician life and good health, the value of which cannot be estimated in money; from a teacher of the liberal sciences you buy the education of a gentleman and mental culture; therefore you pay these persons the price, not of what they give us, but of their trouble in giving it; you pay them for devoting their attention to us, for disregarding their own affairs to attend to us: they receive the price, not of their se
