I am writing an essay on the 'goodness' of both Finny &Gene?I have found several situations where one or both are good.
My problem is that in some scenes where one character is good, the other is not. How do overcome this problem in the essay. Do I ignore the character that demonstrates negative attributes? Or do I somehow discuss these negative issues? In either case, how do I account for this in my thesis?
Are not good and bad just the proverbial "two sides of the coin"? Why not use these situations to show that Phineas and Gene act at times as foils to one another. For, it is often the case that because of Finny's goodness Gene acts in the vindictive or envious way that he does. After all, throughout the novel, Gene constantly compares and contrasts himself with Finny.
The most salient instance of Gene's measuring himself against Finny and then reacting in an immoral way is in Gene's assumption that Finny wishes to prevent him from doing well out of envy. When Finny proves Gene wrong in this theory by encouraging Gene in his studies, Gene reacts by finding this knowledge intolerable. It is after this that, out of his pettiness, Gene impulsively jounces the limb that causes Finny's tragic accident.
Concerning the essay you're writing about A Separate Peace, I suggest you alter your thought and thesis slightly.
First, well-developed characters in good fiction are usually mixtures of positive and negative personality traits, or good and bad, as you say. You seem to want to show that both are just good, since you mention wanting to ignore the character that doesn't show goodness in a particular scene. That's probably a mistake. A literary character doesn't have to be completely good. It doesn't take anything away from the character to show the negative. That makes a character more realistic.
Furthermore, just because both characters have goodness in them, doesn't mean they have to show it in the same scene. Can't you just show goodness in Gene is a few scenes, and goodness in Finny in a few different scenes?
I guess what I'm suggesting is that you really don't have a problem. Just make sure your thesis doesn't try to argue that either character is completely or totally good.
In looking at your question I would set my essay up to demonstrate the good in each character as a separate thing. For example, no human being is going to be good all the time or at the same time as someone else.
Separate your sections to include one discussing Finny's good behavior and listing times when he demonstrated goodness and how it related to Gene or another character.
Next, set-up a section for Gene that addresses what his good features are and the times when he demonstrated his goodness.
You can discuss how one may have perceived the other's behavior as negative and include that in a separate section.