How does Gene learn about friendship, jealousy, hatred, and war in John Knowles's A Separate Peace?
Gene learns about friendship and jealousy during his escapades with Phineas during the summer session of school before their senior year and throughout the following year. He compares himself to Finny so much that he becomes paranoid that his best friend is out to get him. As a result, he contributes to Finny breaking his leg; and, it is after this point that Gene realizes his darker self. As he comes to terms with his friend, he learns how to be a better friend himself. As far as war and hatred are concerned, though, Gene learns about these two topics mostly through Leper's mental breakdown and his dismissal from the military. Leper's jealousy turned to hatred as he felt that he couldn't measure up to other men his age or in the military. Leper later testifies against Gene about how Finny's leg broke in a very malicious way. Other than that, Gene learns about the war through his own service in the military, but never went overseas to fight because the war ended before his training was complete.