 A second problem is an arbitrary distinction between severely cognitively impaired humans and members of other similarly cognitively sophisticated species, were they to exist, who have analogous severe cognitive impairments. Imagine, for example, a cognitively sophisticated biological species of “Martians,” which has some severely cognitively impaired members. Even if an impaired Martian and an impaired human have similarly limited cognitive capacities, and even though they bear the same metaphysical relation to members of their species (they are both tokens of a biological type whose unimpaired members are cognitively sophisticated), this account nevertheless treats them as having a different moral status. This is unacceptably arbitrary.