I. He who first compared the arts to our senses seems to me to have especially alluded to the power which they both exhibit of dealing with objects of completely contrary qualities. In this respect they coincide; but they differ in respect of the use and purpose of the object of which they take cognisance. Our senses are influenced indifferently by things white or black, sweet or bitter, soft or hard, for the proper function of each sense is merely to receive all these impressions and to convey them to the mind. But the arts, which have been invented in order to cultivate the qualities proper to their own nature and to eschew those which are foreign to it, view some with especial favour, as partaking of their own essence, and avoid others as mere untoward accidents. Thus the art of medicine deals with diseases and the art of music deals with discord merely with a view to produce their respective opposites; while self-control, justice and wisdom, which are the most perfect of all arts, because they decide not only what is honourable, righteous and useful but likewise what is hurtful, shameful, and unjust, do not praise innocency which prides itself upon inexperience of evil, but think it to be folly and ignorance of what all who intend to live as becomes them ought to know. The ancient Spartans at their feasts used to compel their helots to drink a large quantity of wine, and then brought them into the banqueting-hall, in order to show the young Spartans what drunkenness was like. I think that to instruct one class of men by the ruin of another is neither humane nor politic, yet I conceive that it may be useful to insert among my Parallel Lives some examples of men who have been careless of their own reputation, and who have used their great place and power only to make themselves notorious for evil. The description of such men's lives is not indeed an agreeable task, or a pleasant mode of employing my leisure, still, as Ismenias the Theban, when instructing his scholars how to play the flute, used to say, "Thus you should play;" and again, "Thus you should not play," while Antigenides even thought that the young would take more pleasure in listening to good flute-players, if they had first heard bad ones, so I think that we shall be more inclined both to admire and to imitate the lives of good men, if we are well acquainted with those of bad ones. This book, then, will contain the lives of Demetrius, surnamed the City-taker, and of Antonius the Triumvir, men who bear signal witness to the truth of Plato's remark, that great men have great vices as well as great virtues. Both alike loved passionately, drank deep, and fought bravely; both were freehanded, extravagant and arrogant. Fortune served them both alike, not only in their lives, for each of them had great successes and great disasters, each won great empire and lost it again, each unexpectedly fell and rose again; but also in their deaths, as the