The satiric novel Gulliverās Travels (1726) by Jonathan Swift contrasts the rational, communal, and benevolent Houyhnhnms with the brutish, greedy Yahoos. The Houyhnhnms, a race of horses, have no words for deception or evil. The humanoid Yahoos are described as filthy and selfish. In the bookās ending, the narrator Lemuel Gulliver must leave the Houyhnhnms. He returns to England, so disgusted with humanity that he avoids his family and buys horses and converses with them instead.
Gulliverās own proud identification with these horses and his disdain for his fellow humans indicate that he too has become imbalanced and that human beings are simply incapable of aspiring to the perfect rationality of the Houyhnhnms.