Averroes' Paraphrase of Plato's Republic

for example, the part capable of science is more excellent in the Greeks; in the Gauls and other such nations, irascibility is more present. And indeed, this place is of an excellent question: when wherever that part addicted to science flourishes, there also the virtues are more appropriate and more excellent, and that by natural excellence. However, whatever the matter may be, it is so arranged in the greater part of the nations that virtues of this kind are dispensed and spread through those nations, especially in this fifth and fourth region (others call it a climate), which are more temperate than the rest. And this seems to make for Plato, who says that men can be possessed of such virtues if they have been educated and engaged in them from their tender years, as they say, from the fingernails. Once these years have passed, however, if they have excluded these virtues, no hope is left for them any longer. Therefore, neither rebuke nor punishment will have any momentum for those who are already of more advanced age and were not educated in industrious administration. Sometimes it is necessary that this be done by forcibly taking away their children, who may be instructed in virtues. Nor is it impossible that virtue may be acquired to some extent by very many whose youth has passed, and this primarily, even if they have not been educated in that institution which is most nearly related to virtue. If not even that happens for them, then it is necessary that one of these two things happens to them: namely, that they be killed or that they be enslaved. And they should be in the Republic almost in the place of irrational animals.
individually, there is no way but rebuke