The generation that came of age during World War I is often called the "Lost Generation," a phrase popularized by Gertrude Stein and Hemingway. This phrase refers to those who had experienced the horrific devastation of global war and, as a result, could not find meaning in life anymore, feeling adrift in a world without values. Frederic can be seen as typifying this sense of being lost. Although he is an officer in the army, he is often seen as passive. In the opening chapters, little is revealed about him except that he spends his time drinking with his fellow officers and going to brothels. When he describes troop movements, he seems to be outside the action. He naively thinks that as an ambulance supervisor, he is protected from being hurt. Others also seem trapped in this feeling of being lost. For example, his friend Rinaldi does valued work as a surgeon and is constantly improving his skills with all of the battlefield wounds, but the stress of repairing broken bodies makes him increasing bitter and desperate. Subsequently, he only finding temporary pleasures in alcohol and sex with prostitutes.

Opposed to this life of negation is Catherine Barkley.