Watch-dogs

To keep watch-dogs, who, from want of discipline or hunger, or some evil habit or other, would turn upon the sheep and worry them, and behave not like dogs but wolves, would be a foul and monstrous thing in a shepherd?

Truly monstrous, he said.

And therefore every care must be taken that our auxiliaries, being stronger than our citizens, may not grow to be too much for them and become savage tyrants instead of friends and allies?

Yes, great care should be taken.

And would not a really good education furnish the best safeguard?

But they are well-educated already, he replied.

I cannot be so confident, my dear Glaucon, I said; I am much more certain that they ought to be, and that true education, whatever that may be, will have the greatest tendency to civilize and humanize them in their relations to one another, and to those who are under their protection.