In many ways, Peter Pan is a playful story about the innocence of childhood, but the symbolism of Peter's shadow—which can be detached from the rest of him, a flat and uninteresting piece of matter in the shape of its former owner—can be interpreted rather darkly. J. M. Barrie's novel opens with the declaration that "all children except one grow up" and states that "growing up is the beginning of the end." It has long been suggested that Peter Pan and his lost boys—"babies who fell out of their prams"—are in fact the spirits of dead children gone to a Neverland in which they will never grow up. In this interpretation, then, Peter's shadow, albeit described with a light touch in the story, would seem to represent his physical body or physical life, tied to the earth. It is a "shadow" of the whole person he is in the same way that a corpse is only a thing in the shape of a deceased person, and our memories of a person who has passed on are only a shadow of who that person truly was. It is particularly notable that Peter becomes distressed when he realizes his shadow is detached from him, attempts to reattach it with soap, and then behaves—after Wendy has sewn it back on—as if he was able to reunite himself with it easily, a rejection of the true facts of the matter. It is as if Peter does not want to face the reality that he and his shadow are no longer naturally attached to each other.
J. M. Barrie himself never grew taller than five feet, and, in many ways, Peter Pan is often thought to be his avatar, but Barrie was also strongly influenced by the death of his older brother, David, in a skating accident in childhood. So, Peter can be seen to represent not only the continued physical childishness of Barrie, but also those children suspended in a perpetual Neverland of the mind, never achieving adult understanding of the world because of their untimely deaths.