Why does Darl burn down the barn?

Darl burns down the barn in William Faulkner's "As I Lay Dying" as a desperate act to liberate his mother, Addie Bundren, from what he perceives as an unworthy burial. He believes that by destroying the barn, he is also releasing the family's struggles and the burden of their journey to fulfill Addie's last wish. This act reflects Darl's complex mental state and deep connection to his mother's death, highlighting themes of isolation and existential despair within the novel. Ultimately, it serves as a pivotal moment that underscores the family's disintegration.