*7* Placet igitur, quoniam omnis disputatio de officio futura est, ante definire, quid sit officium; quod a Panaetio praetermissum esse miror. Omnis enim, quae [a] ratione[7] suscipitur de aliqua re institutio, debet a definitione proficisci, ut intellegatur, quid sit id, de quo disputetur....[8] [4] _et neglegendo_ A H a b, Edd.; _et in neglegendo_ B c. [5] _dilectum_ B H a b, Edd.; _delectum_ A c. [6] _sequemur_ Graevius, Edd.; _sequimur_ MSS. [7] [_a_] _ratione_ Ed.; _a ratione_ MSS.; _ratione_ Müller. [8] Cicero's definition must have followed here, something like _Omne igitur, quod ratione actum est officium appellamus_ Unger. #Statement of subject.# II. But since I have decided to write you a little now (and a great deal by and by), I wish, if possible, to begin with a matter most suited at once to your years and to my position. Although philosophy offers many problems, both important and useful, that have been fully and carefully discussed by philosophers, those teachings which have been handed down on the subject of moral duties seem to have the widest practical application. For no phase of life, whether public or private, whether in business or in the home, whether one is working on what concerns oneself alone or dealing with another, can be without its moral duty; on the discharge of such duties depends all that is morally right, and on their neglect all that is morally wrong in life. #The philosophic schools and ethical teaching.# *5* Moreover, the subject of this inquiry is the common property of all philosophers; for who would presume to call himself a philosopher, if he did not inculcate any lessons of duty? But there are some schools that distort all notions of duty by the theories they propose touching the supreme good and the supreme evil. For he who posits the supreme good as having no connection with virtue and measures it not by a moral standard but by his own interests--if he should be consistent and not rather at times over-ruled by his better nature, he could value neither friendship nor justice nor generosity; and brave he surely cannot possibly be that counts pain the supreme evil, nor temperate he that holds pleasure to be the supreme good. #Reasons for choice of subject and authorities.#