In the final chapter of his novel John Knowles's narrator, Gene Forrester concludes from his return to Devon School,
Because it seemed clear that wars were not made by generations and their special stupidities, but that wars were made instead by something ignorant in the human heart.
Only Phineas never was afraid, only Phineas never hated anyone. Other people experienced this fearful shock somewhere, this sighting of the enemy, and so began an obsessive labor of defense, began to parry the menace they saw facing them by developing a particular frame of mind.
Certainly, much hatred is born of fear and envy and a sense of inferiority, and it is this truth that Gene realizes upon his return in order to retrace his life at Devon School. Confronting the the superiority of athleticism and popularity and joie de vivre in the person of Phineas, Gene fears the competition that Finny presents him. He also feels that Phineas is jealous of his academic success, and fears that Finny takes him from his studies at night to participate in the Secret Suicide Society in order to keep him from good grades. But, when Finny encourages him one night to study rather than join in the society's activities, Gene realizes that Finny has never envied him. Instead of being relieved, however, Gene finds this knowledge intolerable as it points to his own inferiority of character. Then, Gene becomes envious of Finny,who is "too unusual for rivalry." And, it is in this state of envy, that Gene jounces the limb, causing Finny to fall and break his leg; it is because of that "something ignorant in his heart" that Gene harms his good friend, Phineas, with whom he wages his private war.