The key events in the formation of Jake’s character occur long before the novel’s action begins. As a soldier in World War I, Jake is wounded. Although he does not say so directly, there are numerous moments in the novel when he implies that, as a result of his injury, he has lost the ability to have sex. Jake’s narration is characterized by subtlety and implication. He prefers to hint at things rather than state them outright, especially when they concern the war or his injury. Early in the novel, for example one must read the text very closely to grasp the true nature of Jake’s wound; it is only later, when Jake goes fishing with Bill, that he speaks more openly about his impotence.
Jake’s physical malady has profound psychological consequences. He seems quite insecure about his masculinity. The fact that Brett, the love of his life, refuses to enter into a relationship with him compounds this problem. Jake, with typical subtlety, suggests that she does not want to because it would mean giving up sexual intercourse. Jake’s hostility toward Robert Cohn is perhaps rooted in his own feelings of inadequacy. In many ways, Jake is a typical member of what poet Gertrude Stein called the “lost generation,” the generation of men and women whose experiences in World War I undermined their belief in justice, morality, manhood, and love. Without these ideals to rely on, the Lost Generation lived an aimless, immoral existence, devoid of true emotion and characterized by casual interpersonal cruelty. Part of Jake’s character represents the Lost Generation and its unfortunate position: he wanders through Paris, going from bar to bar and drinking heavily at each, his life filled with purposeless debauchery. He demonstrates the capacity to be extremely cruel, especially toward Cohn. His insecurities about his masculinity are typical of the anxieties that many members of the Lost Generation felt.
Yet, in some important ways, Jake differs from those around him. He seems aware of the fruitlessness of the Lost Generation’s way of life. He tells Cohn in Chapter II: “You can’t get away from yourself by moving from one place to another.” Moreover, he recognizes the frequent cruelty of the behavior in which he and his friends engage. Most important, perhaps, he acknowledges, if only indirectly, the pain that his war injury and his unrequited love for Brett cause him. However, though Jake does perceive the problems in his life, he seems either unwilling or unable to remedy them. Though he understands the dilemma of the Lost Generation, he remains trapped within it.