one may, as you often do yourselves, suppose anything for the purpose of illustration,) if, then, that culture of the vine be in the vine itself, it would, I presume, desire everything else which concerns the cultivation of the vine, to be as it has been before. But it would prefer itself to every separate part of the vine, and it would feel sure that nothing in the vine was better than itself. In like manner sense, when it has been added to nature, protects it indeed, but it also protects itself. But when reason is also added, then it is placed in a position of such predominant power, that all those first principles of nature are put under its guardianship. Therefore it does not abandon the care of those things over which it is so set, that its duty is to regulate the entire life: so that we cannot sufficiently marvel at their inconsistency. For they assert that the natural appetite, which they call ὁρμὴ, and also duty, and even virtue herself, are all protectors of those things which are according to nature. But when they wish to arrive at the chief good, they overleap everything, and leave us two tasks instead of one—namely, to choose some things and desire others, instead of including both under one head.
XV. But now you say that virtue cannot properly be established, if those things which are external to virtue have any influence on living happily. But the exact contrary is the case. For virtue cannot possibly be introduced, unless everything which it chooses and which it neglects is all referred to one general end. For if we entirely neglect ourselves, we then fall into the vices and errors of Ariston, and shall forget the principles which we have attributed to virtue itself. But if we do not neglect those things, and yet do not refer them to the chief good, we shall not be very far removed from the trivialities of Herillus. For we shall have to adopt two different plans of conduct in life: for he makes out that there are two chief goods unconnected with each other; but if they were real goods, they ought to be united; but at present they are separated, so that they never can be united. But nothing can be more perverse than this. Therefore, the fact is exactly contrary to your assertion: for virtue cannot possibly be established firmly, unless it maintains those things which are the principles of nature as having an influence on the object. For we have been looking
