The quote "They are mad; they are fools," spoken by the Dog-man in H.G. Wells' "The Island of Doctor Moreau," captures a significant theme of the novel concerning the nature of sanity and morality. The Dog-man, a creature that embodies both human and animal traits, reflects the complex dynamics of the characters on the island and their descent into madness. This commentary on sanity raises questions about what it means to be civilized versus being primal.