But it is not difficult to perceive that those who maintain the contrary opinion have some reason on their side; for a man may become a slave two different ways; for he may be so by law also, and this law is a certain compact, by which whatsoever is taken in battle is adjudged to be the property of the conquerors: but many persons who are conversant in law call in question this pretended right, and say that it would be hard that a man should be compelled by violence to be the slave and subject of another who had the power to compel him, and was his superior in strength; and upon this subject, even of those who are wise, some think one way and some another; but the cause of this doubt and variety of opinions arises from hence, that great abilities, when accompanied with proper means, are generally able to succeed by force: for victory is always owing to a superiority in some advantageous circumstances; so that it seems that force never prevails but in consequence of great abilities. But still the dispute concerning the justice of it remains; for some persons think, that justice consists in benevolence, others think it just that the powerful should govern: in the midst of these contrary opinions, there are no reasons sufficient to convince us, that the right of being master and governor ought not to be placed with those who have the greatest abilities. Some persons, entirely resting upon the right which the law gives (for that which is legal is in some respects just), insist upon it that slavery occasioned by war is just, not that they say it is wholly so, for it may happen that the principle upon which the wars were commenced is unjust; moreover no one will say that a man who is unworthily in slavery is therefore a slave; for if so, men of the noblest families might happen to be slaves, and the descendants of slaves, if they should chance to be taken prisoners in war and sold: to avoid this difficulty they say that such persons should not be called slaves, but barbarians only should; but when they say this, they do nothing more than inquire who is a slave by nature, which was what we at first said; for we must acknowledge that there are some persons who, wherever they are, must necessarily be slaves, but others in no situation; thus also it is with those of noble descent: it is not only in their own country that they are Esteemed as such, but everywhere, but the barbarians are respected on this account at home only; as if nobility and freedom were of two sorts, the one universal, the other not so. Thus says the Helen of Theodectes:

Those who express sentiments like these, shew only that they distinguish the slave and the freeman, the noble and the ignoble from each other by their virtues and their [1255b] vices; for they think it reasonable, that as a man begets a man, and a beast a beast, so from a good man, a good man should be descended; and this is what nature desires to do, but frequently cannot accomplish it. It is evident then that this doubt has some reason in it, and that these persons are not slaves, and those freemen, by the appointment of nature; and also that in some instances it is sufficiently clear, that it is advantageous to both parties for this man to be a slave, and that to be a master, and that it is right and just, that some should be governed, and others govern, in the manner that nature intended; of which sort of government is that which a master exercises over a slave. But to govern ill is disadvantageous to both; for the same thing is useful to the part and to the whole, to the body and to the soul; but the slave is as it were a part of the master, as if he were an animated part of his body, though separate. For which reason a mutual utility and friendship may subsist between the master and the slave, I mean when they are placed by nature in that relation to each other, for the contrary takes place amongst those who are reduced to slavery by the law, or by conquest.