The Illustrated Guide to Criminal Law
Chapter 5: The Three “R”s 
Page 4: Civilized Punishment

If we were consistent with these ostensibly civilized reasons for punishment, it would not make sense to say “This crime will get you 5 years in prison.”

Instead, such a “civilized” sentence would be purely INDEFINITE:

Your punishment would last until it wasn’t needed any more—potentially lasting FOREVER.

Skeleton chained to wall of dungeon

But this is hardly a civilized thing to do. That’s the stuff of medieval DUNGEONS and tyrants’ gulags, not something we associate with modern JUSTICE.