"Some persons hold that, while it is proper for the lawgiver to encourage and exhort men to virtue on moral grounds, in the expectation that those who have had a virtuous moral upbringing will respond, yet he is bound to impose chastisement and penalties on the disobedient and ill-conditioned, and to banish the incorrigible out of the state altogether. For (they argue) although the virtuous man, who guides his life by moral ideals, will be obedient to reason, the base, whose desires are fixed on pleasure, must be chastised by pain, like a beast of burden."