Cohen can babble all he wants about how one ought to treat fellow citizens in a communist society like relatives. (225)
But none of the problems plaguing socialist egalitarianism afflict the family.
The incentive problem is overcome, because the husband and wife love each other with intense, personal, and intelligent charity-love. Their wills are intertwined: such love is marked, as St. Thomas teaches, by union, mutual indwelling (of souls), ecstasy, and zeal (in acting for the sake of the beloved). Each spouse considers, nay, feels the welfare of the other to be as important as their own. They have no general duty to sacrifice for each other, because they are to a great extent one heart not just one flesh.
The computation problem is overcome, because a typical household economy is technologically exceedingly simple.
I will even grant to him that if one could treat citizens like relatives, then it would have to be done. Imagine a society of paradise, a communion of saints in which “there is no loss of individuality, yet such an interdependence that the saints are ‘members one of another,’ not only sharing the same blessings and exchanging good offices and prayers, but also partaking of the same corporate life…” Imagine further that the omniscient Jesus is the chief central planner for whom the computation problem is not an obstacle. Then, if there is any sort of production going on in paradise, it could well be perfectly efficient socialism.
(It’s a rather grotesque example, though, and I don’t actually think that’s how the heaven / paradise system works.)
Cohen may regret that earth is not heaven; he may even insist that “justice” calls for earth to be heaven; but as he himself fully realizes, reality and facts of life can make justice unattainable.