Come, now let them teach us, or rather do so yourself, (for who is better able?) in what way you proceed from these principles, and prove that to live honourably (for that is the meaning of living according to virtue, or in a manner suitable to nature) is the chief good; and in what manner, or in what place, you on a sudden get rid of the body, and leave all those things which, as they are according to nature, are out of our own power; and, lastly, how you get rid of duty itself.
I ask, therefore, how it is that all these recommendations, having proceeded from nature, are suddenly abandoned by wisdom? But if it were not the chief good of man that we were inquiring into, but only that of some animal, and if he were nothing except mind (for we may make such a supposition as that, in order more easily to discover the truth), still this chief good of yours would not belong to that mind. For it would wish for good health, for freedom from pain; it would also desire the preservation of itself, and the guardianship of these qualities, and it would appoint as its own end to live according to nature, which is, as I have said, to have those things which are according to nature, either all of them, or most of them, and all the most important ones. For whatever kind of animal you make him out, it is necessary, even though he be incorporeal, as we are supposing him, still that there must be in the mind something like those qualities which exist in the body; so that the chief good cannot possibly be defined in any other manner but that which I have mentioned.
But Chrysippus, when explaining the differences between living creatures, says, that some excel in their bodies, others in their minds, some in both. And then he argues thatthere ought to be a separate chief good for each description of creature. But as he had placed man in such a class that he attributed to him excellence of mind, he determined that his chief good was not that he appeared to excel in mind, but that he appeared to be nothing else but mind.