Kitap 1
1255b
for they assume that just as from a man springs a man and from brutes a brute, so also from good parents comes a good son but as a matter of fact nature frequently while intending to do this is unable to bring it about.
1255b
It is clear therefore that there is some reason for this dispute, and that in some instances it is not the case that one set are slaves and the other freemen by nature; and also that in some instances such a distinction does exist, when slavery for the one and mastership for the other are advantageous and just, and it is proper for the one party to be governed and for the other to govern by the form of government for which they are by nature fitted, and therefore by the exercise of mastership, while to govern badly is to govern disadvantageously for both parties (for the same thing is advantageous for a part and for the whole body or the whole soul, and the slave is a part of the master—he is, as it were, a part of the body, alive but yet separated from it; hence there is a certain community of interest and friendship between slave and master in cases when they have been qualified by nature for those positions, although when they do not hold them in that way but by law and by constraint of force the opposite is the case).
