* The Nature of Innocence and its Loss: The story centers around Gene's journey from a naive, idealistic boy to a more complex, disillusioned young man. He loses his innocence through his rivalry with Finny, his guilt over the accident, and the realization of the destructive nature of war. The novel suggests that innocence is a fragile thing, easily lost in the face of the complexities of life and human nature.
* The Power of Friendship: Despite their rivalry and the tragic events that unfold, Gene and Finny share a deep and profound friendship. The novel argues that friendship can be a powerful force, capable of both love and destruction.
* The Psychological Effects of War: Although the war is not directly experienced by the boys at Devon, it looms large in the background, casting a shadow over their lives and influencing their choices. The novel suggests that the psychological effects of war can be profound, even for those who do not directly participate in the fighting.
* The Importance of Self-Discovery: Gene's journey is one of self-discovery. Through his relationship with Finny, his encounter with the realities of war, and his struggle with guilt and responsibility, Gene begins to understand himself and his place in the world. The novel argues that self-discovery is a crucial part of growing up and finding meaning in life.
Ultimately, *A Separate Peace* doesn't offer a simple, straightforward thesis statement. Instead, it explores these complex themes through the lens of a coming-of-age story, leaving readers to draw their own conclusions about the nature of innocence, friendship, war, and the human condition.