Human uses of mammals that "one is well advised to study the behaviour rather than attempting to get at any underlying emotion". Charles Darwin however had accepted the idea of emotion in animals, writing his 1872 book "The Expression of the Emotions in Man and Animals" on the subject. Darwin believed that mammals had social, mental and moral lives. In "The Descent of Man" (1871), he wrote: "There is no fundamental difference between man and the higher mammals in their mental faculties." Biologists remained wary of the idea, even for the great apes, but this led to serious difficulties, as Donald O. Hebb explained
The Man in the Moone la Lune" (1657); Cyrano's traveller actually meets Gonsales, who is still on the Moon, "degraded to the status of pet monkey". It was one of the inspirations for what has been called the first science fiction text in the Americas, "Syzygies and Lunar Quadratures Aligned to the Meridian of Mérida of the Yucatán by an Anctitone or Inhabitant of the Moon ..." by Manuel Antonio de Rivas (1775). The Laputan language of Jonathan Swift, who was a distant relation of Godwin's, may have been influenced by "The Man in the Moone", either directly or through Cyrano de Bergerac. "The Man