It begins with an allegory suggestive of the premise of the science-fiction novel A Canticle for Leibowitz: a world where all sciences have been dismantled quickly and completely. MacIntyre asks what the sciences would look like if they were re-assembled from the remnants of scientific knowledge that survived the catastrophe. He claims that the new sciences, though superficially similar to the old, would in fact be devoid of real scientific content, because the key suppositions and attitudes would not be present. "The hypothesis which I wish to advance," he continues, "is that in the actual world which we inhabit the language of morality is in the same state of grave disorder as the language of natural science in the imaginary world which I described.
https://en.wikipedia.org/wiki/After_Virtue