Maupassant was strongly influenced by the pessimistic philosophy of the German philosopher Arthur Schopenhauer. He declared that Schopenhauer had "stamped mankind with the seal of his disdain and disenchantment... He has upset belief, hope, poetry, fantasy, destroyed aspirations, ravaged confidence, killed love, overthrown the idealistic cult of womanhood, murdered the illusions of the heart, and altogether performed the most gigantic sceptical operation ever carried out. He has riddled everything with his mockery, and drained everything dry."
Maupassant was also strongly influenced by the famous French realist Gustave Flaubert, who was his uncle (and thought by some to be his father). Flaubert's best-known work is the novel "Madame Bovary," in which some of Maupassant's favorite themes can be seen. Flaubert tutored his young nephew vigorously over a long period of time and would not let him publish until he felt satisfied with his work. Flaubert was also cynical and pessimistic about human nature, and this influence can also be seen in Maupassant's style. Maupassant turned out to be a much better writer than Flaubert because the younger man had more talent and more love of life.
Maupassant contracted syphilis as a result of his many romantic liaisons and his later writings show a nihilism and despair which are not seen in his earlier stories. His weird story titled "The Horla" shows his deteriorating mental condition. He published nearly four hundred short stories in his lifetime as well as five novels and a great deal of nonfiction.