What is the main conflict in Stoner by John Williams?

William Stoner is born into a farming family in rural Missouri in the late 1800s. He attends University and falls in love with English literature. He becomes a professor and teaches for decades through numerous personal and political struggles until his death. In his early life, Stoner knew only the farm and had scarcely traveled more than several miles away from it. When he is twenty he goes to the University of Missouri to study agriculture but winds up changing majors when he falls in love with English. Before his graduation, one of his teachers, Archer Sloane, sensing his love for literature, suggests that Stoner continue his studies and obtain his doctoral degree and Stoner accepts. Two of his friends, David Masters and Gordon Finch, leave the university to enlist and fight in World War I. They urge that he come along, but he decides against it after consulting with Sloane, who argues that armed conflict is antithetical to the creative, civilizing work of the intellectual. David Masters is killed in combat.