Adam’s knapsack
Adam's knapsack symbolizes his uncertainty about happiness. Inside the knapsack are notebooks and other scientific study materials entailing Adam's secretive study about happiness. Despite having a close-knit family, Adam never experienced true happiness, pushing him to conduct secretive experiments on his family. One day, when Adam failed to return home with his son, the family reported the matter to the police. Investigators closely studied the contents of the knapsack and concluded that Adam wanted to know how happiness could be quantified to gauge his family's cheerfulness.
Potomac River
The Potomac River symbolizes Adam's hiking routine with his son, Eugene. The family knew that Adam was the primary caregiver for Eugene, and he always ensured his safety. The river flowed in a similar direction, representing Adam's routine until he failed to return home with his son after the morning hike. Adam's disappearance remains a mystery throughout the novel.
Eugene
Eugene is a fourteen-year-old autistic boy representing the challenges disabled children go through in society. Eugene does not talk, and most people do not understand him. Most of the time, Eugene is misunderstood by his family and friends. Consequently, people misunderstand Eugene's needs. In society, people are not keen on studying the needs of disabled kids, and they end up hurting these innocent children instead of helping them cope with their challenges.
