Reality vs. memory
Gene often shows how memory can be tinged by feelings that change how reality is perceived and recalled. This is especially evident when he looks for a tree by the river that has a special meaning to him. "It had loomed in my memory as a huge lone spike dominating the riverbank, forbidding as an artillery piece, high as a beanstalk," he says, his similes characterizing the tree as a great, forbidding mass (5). Yet, when he sees it, he finds it "absolutely smaller, shrunken with age," and nothing like the great giant he had remembered. Perhaps the tree had actually shrunk since Gene's time; but this is a more apt example how things can be obscured or emphasized in the memory via emotional factors, and a good introduction of the theme of memory versus reality. Gene remembers his old campus in one way, yet when he visits, he finds it quite different; this happens often, as things can seem less imposing or important when revisited, yet be so huge in one's memory.
Rebellion vs. conformity
Gene and Finny are a great example of this theme in action; Gene is naturally a rule-abiding person, and Finny has an absolute disregard for rules. This difference is also represented in the differences between the summer session and the fall session. Finny himself embodies both of those, as he is