text: Posidonius holds that not only precept-giving (there is nothing to prevent my using this word), but even persuasion, consolation, and encouragement, are necessary. To these he adds the investigation of causes (but I fail to see why I should not dare to call it aetiology, since the scholars who mount guard over the Latin language thus use the term as having the right to do so). He remarks that it will also be useful to illustrate each particular virtue; this science Posidonius calls ethology, while others call it characterization. It gives the signs and marks which belong to each virtue and vice, so that by them distinction may be drawn between like things. Its function is the same as that of precept. For he who utters precepts says: "If you would have self-control, act thus and so!" He who illustrates, says "The man who acts thus and so, and refrains from certain other things, possesses self-control." If you ask what the difference here is, I say that the one gives the precepts of virtue, the other its embodiment. These illustrations, or, to use a commercial term, these samples, have, I confess, a certain utility; just put them up for exhibition well recommended, and you will find men to copy them. Would you, for instance, deem it a useful thing to have evidence given you by which you may recognize a thoroughbred horse, and not be cheated in your purchase or waste your time over a low-bred animal? But how much more useful it is to know the marks of a surpassingly fine soul – marks which one may appropriate from another for oneself!