Fairness and Restitution
The first thing to notice about this objection is that it would apply to any reform that makes people’s lives better in the present. If we passed Medicare for All, no one from that point forward would have to pay for private health insurance premiums, co-pays, or deductibles again. Would this be unjust to everyone who had to pay through the nose for all of these things in the past?
Or think about all the states that have legalized recreational marijuana. Is this unfair to all the people in those states who had to pay fines or serve time in prison for possession in the past?
It would certainly be unfair to keep people who hadn’t finished their sentences yet in prison after legalization. (This would be the equivalent of ending tuition without providing relief for people who were still struggling to pay off their loans.) But even there it’s important to make a basic distinction. The unfairness of keeping people in prison for what was now legal would be a reason to free the prisoners. It wouldn’t be a reason to keep marijuana illegal going forward.
If a monster lives at the edge of town and makes a regular practice of eating bits and pieces of passersby, and after this goes on for years before the town finally brings in a monster hunter to put an end to it, do the people walking around with missing fingers because of past monster attacks have a legitimate complaint? In one sense they do, and in another they don’t. It was unfair to these past victims that it took the town so long to bring in the monster hunter. It’s not unfair that they’re finally taking care of the problem.
Money can’t make up for missing fingers, but it might still be reasonable to financially compensate the past victims of the negligence of the local government. But what if we sharpen the example and have the monster kill its victims instead of just eating the occasional finger? There’s no way to make restitution to the dead, but it would be (ahem) monstrous to treat that as a reason to let the monster continue to eat people now.
After any reform is passed that ends an injustice, an abstract moral case can always be made for some form of reparations for past victims of that injustice. In some cases, it might make sense to actually do this. In others, it might be impractical or even impossible. But whether it’s reasonable or possible to compensate people who have suffered in the past, that’s never a reason not to end an injustice in the present.