When aggregate wealth is increasing, the condition of those at the bottom of society, and in the world, can improve, even while the distance between them and the better off does not diminish, or even grows. Where such improvement occurs (and it has occurred, on a substantial scale, for many disadvantaged groups), egalitarian justice does not cease to demand equality, but that demand can seem shrill, and even dangerous, if the worse off are steadily growing better off, even though they are not catching up with those above them. When, however, progress must give way to regress, when average material living standards must fall, then poor people and poor nations can no longer hope to approach the levels of amenity which are now enjoyed by the world’s well off. Sharply falling average standards mean that settling for limitless improvement, instead of equality, ceases to be an option, and huge disparities of wealth become correspondingly more intolerable, from a moral point of view.
G. A. Cohen, If You’re an Egalitarian, How Come You’re So Rich?, Cambridge, Massachusetts, 2000, pp. 113-114