Justice demands identity; similarity, however close, will not answer.

Though a mother could not tell her twin sons apart, it would not make it any more just to punish one for the other's sins." "Then you don't believe in the punishment of crime ?" said Henry.
"Most emphatically I do," replied the doctor; "only I don't believe in calling it justice or ascribing it a moral significance.

The punishment of criminals is a matter of public policy and expediency, precisely like measures for the suppression of nuisances or the prevention of epidemics.
It is needful to restrain those who by crime have revealed their likelihood to commit further crimes, and to furnish by their punishment a motive to deter others from crime." "And to deter the criminal himself after his release," added Henry.
"I included him in the word 'others,'" said the doctor.

"The man who is punished is other from the man who did the act, and after punishment he is still other." "Really, doctor," observed Henry, "I don't see that a man who fully believes your theory is in any need of your process for obliterating his sins.

He won't think of blaming himself for them any way." "True," said the doctor, "perfectly true.