There is a very broad theory that society gets the right to hang, as the individual gets the right to defend himself. Suppose she does; there are certain principles which limit this right. Society has got the murderer within four walls; he never can do any more harm. Has society any need to take that man's life to protect itself? If any society has only the right that the individual has, she has no right to inflict the penalty of death, because she can effectually restrain the individual from ever again committing his offence.