1Every inquiry about duty is twofold: one kind concerns the supreme good, the other lies in the precepts by which the conduct of life can be shaped in every respect. 1Of the former kind these are examples: whether all duties are absolute, whether one duty is greater than another, and questions of the same kind. 1But as for the duties whose precepts are handed down, although they concern the supreme good, this is less apparent, because they seem to look more to the ordering of everyday life; 1and it is these that I must explain in these books. 1There is also another division of duty. 8For a duty is called both 'middle' and 'perfect'.
8Perfect duty we may call, I think, 'right', since the Greeks call it katorthoma, while this ordinary duty they call kathekon. 8And they define these terms in such a way that they define what is right as perfect duty; 8middle duty, on the other hand, they say is that for whose performance a plausible reason can be given. 9Threefold, then, as Panaetius thinks, is the deliberation involved in reaching a decision. 9For people are uncertain whether the thing that falls under deliberation is honourable or shameful to do; 9and in considering this their minds are often pulled apart towards opposing opinions. 9Then again they inquire or take counsel whether the thing they are deliberating about conduces or not to the convenience and pleasure of life, to means and abundance of goods, to wealth, to power, by which they may be able to help both themselves and their own; 9all of which deliberation falls under the reckoning of advantage.
9The third kind of uncertainty is when what seems advantageous seems to conflict with the honourable; 9for when advantage seems to snatch the mind towards itself, and the honourable, on the other hand, to call it back to itself, the result is that the mind is torn in deliberating and brings with it a double-edged anxiety of thought. 10In this division, although to leave something out is the greatest fault in dividing, two points have been passed over; 10for people commonly deliberate not only whether a thing is honourable or shameful, but also, when two honourable things are put forward, which is the more honourable, and likewise, when two advantageous things are put forward, which is the more advantageous.
10Thus the scheme which he thought threefold is found to need dividing into five parts. 10First, then, we must discuss the honourable, but in two ways; then in the same way the advantageous; afterwards the comparison between them.