Before revision: Its proponents hold that if human infants, the senile , the comatose, and the cognitively disabled have direct moral status, non-human animals must have a similar status, since there is no known morally relevant characteristic that those marginal-case humans have that animals lack.
After revision: Its proponents hold that if human infants, senile people , the comatose, and cognitively disabled people have direct moral status, non-human animals must have a similar status, since there is no known morally relevant characteristic that those marginal-case humans have that animals lack.