loseyourname said:
I think the mission of any criminal justice system is pretty straightforwardly to reduce crime.
Mission or not, it cannot be the primary
justification for punishing crime.
Not the least because there is no reason to suppose limiting punishment to those actually guilty is more effective in crime reduction than punishing a few non-guilties along with them.
To take an example:
Around 50 AD, there was a sordid murder of a Roman senator by one of his household slaves (if I remember my Tacitus right, the murderer became insanely jealous of his master for appropriating the sexual favours of a young slave in the household, a co-slave the murderer wanted for himself).
Anyway, Roman law was very harsh on this point:
The ENTIRE household of slaves should be put to death if anyone them killed their master.
The Senate debated whether this archaic law, that covered a crime they had hardly known an actual, previous instance of, should be implemented.
They chose to do so, in order to deter rebellion amongst slaves against their master.
This law, which punishes guilty and non-guilty alike must be regarded as spectacularly successful in detterring the crime covered, since it cannot have been that unusual for slaves to harbour murderous feelings towards their masters.
The law in question basically forced slaves to inform upon each other, in order to ensure their individual safety.
To punish guilty&non-guilty alike can be perfectly rational in a deterrence perspective, and has its analogue in earlier logic of war: It is better to kill off the families of rebels as well, in order to prevent bereaved, aggrieved family members from plotting revenge in the future...
Whatever "mission" we want our justice system to have, the primary
justification of it must lie within a principle in which it is clear that
only the guilty ones are to be punished.