all inquiry about duty. Thus, after we have got rid of the opinions of the rest, as there can be no other, this doctrine of the ancients must inevitably prevail.
IX. Therefore, after the fashion of the ancients, which the Stoics also adopt, let us make this beginning:—Every animal loves itself, and as soon as it is born labours to preserve itself, because this is the first desire given to it by nature, to regulate its whole life, to preserve itself, and to be so disposed as it best may in accordance with nature. At the beginning it has such a confused and uncertain kind of organization that it can only just take care of itself, whatever it is; but it does not understand either what it is, or what its powers are, or what its nature is. But when it has advanced a little, and begins to perceive how far anything touches it, or has reference to it, then it begins gradually to improve, and to comprehend itself, and to understand for what cause it has that appetite of the mind which I have spoken of; and begins also to desire those things which it feels to be suited to its nature, and to keep off the contrary. Therefore, in the case of every animal, what it wishes is placed in that thing which is adapted to its nature. And so the chief good is to live according to nature, with the best disposition and the most suitable to nature that can be engendered.
But since every animal has his own peculiar nature, it is plain that the object of each must be to have his nature satisfied. For there is no hindrance to there being some things in common to all other animals, and some common both to men and beasts, since the nature of all is common. But that highest and chief good and evil which we are in search of, is distributed and divided among the different kinds of animals, each having its own peculiar good and evil, adapted to that end which the nature of each class of animal requires. Wherefore, when we say that the chief good to all animals is to live according to nature, this must be understood as if we said that they had all the same chief good. But as it may truly be said to be common to all arts to be conversant about some science, and that there is a separate science belonging to each art, so we may say that it is common to all animals to live according to nature, but that there are different natures; so that the horse has by nature one chief good, the ox another, man another; and yet in all there is one common end; and
