“I am highly optimistic about the prospects for progress in normative ethics. It is evident to me that great progress has already been made since I entered the field in the early 1980s. Unlike many other disciplines in the humanities and social sciences, which in recent years were seduced by bad French philosophy into a lot of silly “post-modern” theorizing that has exposed them to derision and reduced them to irrelevance, analytic philosophy is flourishing.”
— Jeff McMahan, “Normative Ethics: 5 Questions”

“The Ethics of Killing is full to bursting with … thought-experiments, or ‘cases’ as McMahan calls them…. These cases are devised rather than created, modified rather than rewritten, analysed rather than entered into; they invite precisely the epithets with which McMahan’s book has been greeted – ‘novel and ingenious’, Peter Singer tells us on the dust-jacket, rather than, say, ‘wise and insightful’.
— Stephen Mulhall, “Fearful Thoughts”

“There is no document of civilization which is not at the same time a document of barbarism.”
— Walter Benjamin, “Theses on the Philosophy of History”

Eva Feder Kittay on the normative ethics of Singer and McMahan:

Peter Singer focuses on infants who are severely disabled, especially those with severe mental retardation (not those who are beyond the stage of infancy however), while Jeff McMahan considers the congenitally severely mentally retarded (hence- forth CSMR) of any age. …

In his book The Ethics of Killing McMahan makes the argument that it is less bad to kill a CSMR person than to kill ‘one of us’. In the most provoking of Singer’s books, Should the Baby Live? he and co-author Helga Kuhse state quite baldly: ‘We think that some infants with severe disabilities should be killed’ (1985).

…

Since I wrote the article in which I counter McMahan’s claims and arguments, I experienced one of the most profound learning experiences of my life. My daughter now lives in a group home with five other people who are all considered to be severely mentally retarded, and have been so since birth. Two of her housemates lost their fathers within the period of a month. One, a young woman diagnosed with Brett’s syndrome, would be found sitting with tears streaming down her face after she was told that her father was extremely ill and would die. In the case of the other, a young man who invariably greets me with a huge smile, I myself witnessed the howling, wailing grief minutes after his mother and sister informed him of the death of his father. He waited till they left before he began his heart-wrenching sobbing. They most likely left not knowing what he had understood, and only learned of his response when they later spoke to the staff. It is not unreasonable, in the case of this young man, that he held back his grief to spare his mother and sister. We are speaking here of the capacity to understand the very abstract concept of death, the death of a beloved person. So much for cavalier claims that the severely retarded cannot form profound attachments.

McMahan has other characterizations of the CSMR. In EOK, he sometimes speaks of them having the capacities of a chimp, in other places maintains that they have psychological capacities equivalent to that of a dog.

Eva Feder Kittay, “The Ethics of Philosophizing: Ideal Theory and the Exclusion of People with Severe Cognitive Disabilities”