The compilation video below (used in my class on story structure and complied by Chris Huntley) really illustrates the philosophical conflict between the Main Character and the Influence Character, which is the heart of your story’s message.
Once you have viewed the video, note that one says “we’re just alike” and the other says, “we’re nothing alike.” How can they be so blind to the other character’s point of view? Because it is like one saying, “we’re alike because we are both fruit” and the other saying, “we’re nothing alike because you are an apple and I am an orange.”
You see, they are BOTH right, depending on the context. So the real philosophical argument is actually over which of the two contexts is the most truthful or the best way of looking at their relationship and by extension of looking at life. THAT is the theme of the whole story, and the message is which way you, the author, “proves” is best.