Suppose that a bank robber fleeing from police drops a bag of cash on your door step. Are you allowed to keep it? It seems not. You may be innocent of any wrongdoing, and yet you still have to return the money to its rightful owners.
Suppose your mother robs a bank, promptly dies and leaves her wealth, including the stolen money to you. Again, it seems the bank can recover that money. It didn’t rightly belong to your mother, and so he could not rightly pass it on to you.
For practical reasons, we might cut off the period of recovery, so if the bank discovers that your mother robbed them only after you have died and left the money to your children, we might say that it’s been too long or there too many steps between the wrongdoing and the beneficiary. But in principle, it doesn’t seem to matter; this may be easier to see if we talk about a tangible good, say a painting, instead of a liquid asset like cash. Paintings stolen by the Nazis during WWII that can be definitively traced to a last rightful owner are still returned to that owner’s lawful heirs, even if those heirs are multiple generations removed.
Suppose now that your mother kidnaps an incredible artist, forces him to create valuable works of arts, which she then sells. Let’s ask the same questions:
Can the artist recover from your mother the value of the artworks? That seems like the minimum that he is owed.
Can the artist recover from you if your mother dies and leaves you the proceeds? It seems yes (to see this, consider again the case where the paintings themselves are inherited).
We can also look at the other side: suppose the artist died before he could recover from your mother, could the artists children or rightful heirs recover the paintings or the revenue from their sale from your mother? It seems yes: your mother owes the painter, and that credit passes to the painter’s heirs.
Perhaps you can see where this is going. A person kidnapped, forced to labor; a kidnapper, who benefits from the forced labor; the descendants of each, who are still connected in a credit/debt relationship.
This is an argument for a type of reparations for slavery, and I think that it works. Note that it is specific in its application: a specific heir has a claim against another specific heir. The same argument does not seem to support a more general form of reparations, though some of the reasoning may play a part in such an argument.
I’m fairly confident that it wouldn’t work in practice for a number of reasons. But in principle it does: the heirs of the slaver benefit from the theft of the slave’s labor, and the slave’s heirs are deprived of benefit that should have been a part of their inheritance.
Under many conceptions of property rights, this type of reparations for slavery is justified.