I am simply pointing out what the history of ethics shows all too clearly—how much our thinking has been shaped by what our stages omit to mention. The Greek philosophers never really raised the problem of slavery till towards the end of their speech, and then few of them did so with conviction. This happened even though it lay right in the path of their enquiries into political justice and the value of the individual soul. Christianity did raise that problem, because its class background was different and because the world in the Christian era was already in turmoil, so that men were not presented with the narcotic of a happy stability. But Christianity itself did not, until quite recently, raise the problem o the morality of punishment, and particularly of eternal punishment. This failure to raise central questions was not, in either case, complete. Once can find very intelligent and penetrating criticisms of slavery occurring from time to time in Greek writings—even in Aristotle’s defence of that institution. But they are mostly like Rawls’ remark here. They conclude that “this should be investigated some day”. The same thing happens with Christian writings concerning punishment, except that the consideration, “this is a great mystery”, acts as an even more powerful paralytic to though. Not much more powerful, however. Natural inertia, when it coincides with vested interest or the illusion of vested interest, is as strong as gravitation.

Mary Midgley, ‘Duties concerning islands’, Encounter, vol. 60, no. 2 (February 1983), pp. 36-43.