The demand for reparations for the evils of slavery is often met with the argument that present-day white people are not morally responsible for the sufferings of black people under slavery. That is true, so far as it goes—no one now living is an agent of past injustices committed before they were born. That would require backwards causation! But this response misses the point of the demand for reparations. Suppose your parents stole from their neighbor’s family—they broke into their house and burgled it, taking everything that have, even cleaning out their bank account. Suppose the neighbors suffered great financial damage from this theft, from which they never recovered, which blighted their children’s lives. Meanwhile, the thieves prospered on their theft and gave their children every advantage. The result is that you are doing very well in life, but the children of the neighbors are not. Now those impoverished children ask for reparations: they want their parents’ assets back, which were wrongfully taken. They ask you to provide those reparations. It will be to no avail for you to insist that you are not responsible for the sins of your parents—you didn’t commit the burglary and subsequent financial ruin. That is no doubt true, but not to the point—which is that you benefited unjustly from the crimes of your parents. You owe the neighbor’s children the good things that would have been theirs were it not for the theft of their assets. You are benefitting from the theft from their family, and you need to give something back. It is irrelevant that you didn’t commit the original crime; you are benefitting from the ill-gotten gains of that crime, and you need to make amends. Suppose there is a particular vase that was stolen from the neighbor’s house and is now in your possession. The neighbor’s children now ask for that vase back. They have every right to it, even though you didn’t personally take it. You ought to give it back. This is entirely obvious.
Now observe that slavery is (among other things) labor theft: slaves have their labor forcibly taken from them without proper compensation. That labor builds wealth for the slave owners, which they pass on to their children, and so on down the generations. Meanwhile, the children of the slaves suffer the impoverishment resulting from slavery—notably the lack of wealth accumulation. They are victims of economic exploitation, which is a type of theft. Therefore they have the right to reparations. Roughly, those reparations should be calculated according to what the stolen labor would have been worth under non-slavery conditions. None of this depends on the claim that the current beneficiaries of past slavery are responsible for what their forefathers did in order to acquire their wealth; it is, rather, a point about theft and the just allocation of assets. You steal from a person if you exploit them and forcibly take the fruits of their labor. If the slave owners had first stolen the material assets of their victims and only then subjected them to conditions of forced labor, we would all agree that their descendants have a claim on reparations for the initial theft—but the same logic applies to labor theft. Hence the demand for reparations is morally just. It is a further question of how the reparations should be computed and distributed, and whether they would have desirable consequences.