Disillusionment and the search for meaning are two of the central themes in The Sun Also Rises by Ernest Hemingway. The main characters are members of the Lost Generation, a group of American expatriates living abroad, making art and trying to find meaning in life. Each character has their own way of doing that: Jake obsesses about money, for instance, and tries to distract himself from his impotence. In Jake's disillusionment, however, there is the faint hope of rebirth or transformation.
The title itself conveys one of the themes of "The Sun Also Rises." Taken from the Book of Ecclesiastes, the passage is believed to have been written by King Solomon, who himself was disillusioned with life and found it meaningless at the end:
The sun also riseth, and the sun goeth down, and hasteth to his place where he arose.
The characters in Hemingway's novel are ones whom Gertrude Stein names "the lost generation": those who died in the war lost their lives, those who lived lost their purpose. After the disillusionment of World War I life has become meaningless; the sun rises and sets and nothing meaningful changes. Thus, Hemingway's novel challenges the American Dream in this disillusionment with progress and regeneration.
A prevalent theme, then, is The Meaning of Life. The characters must reject the heroic life as they have seen that it mainly leads to death. The romantic life, as embraced by Cohn is rejected, too, as Brett says, "He is not one of us." Others feel that the essence of life is mangaing one's money. Unfortunately, several of the characters are not able to do this, either. To keep his mind off his impotence, Jakes tabulates everything in life: "You could get your money's worth." Another thing Jack has paid for is the literature of Turgenieff that he reads; from this literature he gleans from the effort of reading, an effort that he can utilize to recover from the war. In the nihilist philosophy of Hemingway himself, his characters must find their own meaning in life; they must create their own existences and not rely upon any promises that the rising sun may hold.
Much like in T.S. Eliot's long poem The Waste Land, which also was written in the modernist period and reflects the lingering cultural influence of the massive deaths of World War I, one of the major themes in Hemingway's novel The Sun Also Rises is disillusionment and the faint hope for transformation and rebirth.
Many of the symbols in the novel -- from the fizzling firecrackers that fail to launch in the air at the Spanish fiesta to the raised police baton in Paris at the novel's end -- are connected to the idea of sexual potency. The main character, Jake Barnes, is suffering from a war wound that prevents him from having sexual relations with woman, and these consequences of his wound are probably the source of much of the conflict in the novel. One of the most pastoral scenes in the novel (Ch. 12) involves men spending time together and alone in nature, away from the bustle of the city.
The novel's themes also include religion and the meaning of life, gender roles and relations, expatriates and tourists, work and recreation, passion (aficion), and many others.