Moral Uncertainty and Distributive Sufficiency

According to the sufficiency principle, distributive justice requires that everyone have some sufficient level of resources or well-being, but inequalities above this threshold have no moral significance. This paper defends a version of the sufficiency principle as the appropriate response to moral uncertainty about distributive justice. Assuming that the appropriate response to moral uncertainty is to maximize expected choiceworthiness, and given a reasonable distribution of credence in some familiar views about distributive justice (including libertarianism, sufficientarianism, and egalitarianism), a version of the sufficiency principle strikes the optimal balance between the competing moral risks posed by implementing these views. In particular, it avoids the moral risk posed by views like Nozick’s libertarianism, which forbid redistributive taxation even for the sake of helping to provide for people’s basic needs: failing to do the latter, if it turns out that justice does require it, would be very morally wrong. This “uncertainty argument” has the advantage of minimizing reliance on controversial intuitions about distributive justice, helps to specifying a non-arbitrary threshold for sufficiency, and shows that the substantive moral implications of moral uncertainty are not limited to high-stakes applied ethics issues such as abortion and vegetarianism but instead extend to an issue at the heart of political philosophy.