andy013

Do you think that punishment can be justified if it acts as a deterrent?

In a classroom, for example, if a student misbehaves and is punished, it may dissuade pupils from misbehaving in the future. From a utilitarian standpoint, it is ethical to penalise misbehaving students even if they do not deserve it, because most students are better off in a school with rules.

Even if there is no free will or deservingness, punishment can be justified if it improves society by deterring crime. This seems to go beyond the idea that prisons are just quarantine zones that keep dangerous people away from those they could harm.

Punishing a car will never change it's behaviour. Threat of punishment can deter humans from certain behaviours. You don't need free will for deterrents or incentives to influence your decisions.