To this I answered: "Since indeed you wish to learn from me if there is any good or evil in nature or in act, or whether it is not rather that men, prejudiced by custom, think some things to be good, and others to be evil, forasmuch as they have made a division among themselves of common things, which ought, as you say, to be as common as the air and the sunshine; I think that I ought not to bring before you any statements from any other quarter than from those studies in which you are well versed, and which you support, so that what I say you will receive without hesitation. You assign certain boundaries of all the elements and the heavenly bodies, and these, you say, meet in some without hurt, as in marriages; but in others they are hurtfully united, as in adulteries. And you say that some things are general to all, but other things do not belong to all, and are not general. But not to make a long discussion, I shall speak briefly of the matter. The earth which is dry is in need of the addition and admixture of water, that it may be able to produce fruits, without which man cannot live: this is therefore a legitimate conjunction. On the contrary if the cold of hoar-frost be mixed with the earth, or heat with the water, a conjunction of this sort produces corruption; and this, in such things, is adultery."