"The irrationality of the "appeal to Nature" is illustrated by a simple thought-experiment. Imagine, fancifully, if starvation, disease, parasitism, disembowelling, asphyxiation and being eaten alive were not endemic to the living world — or such miseries have already been abolished and replaced by an earthly paradise. Would anyone propose there is ethical case for (re)introducing them? Even proposing such a thought-experiment can sound faintly ridiculous."