does keller do paul more harm than good?

I think that Keller helps Paul in many ways. He also develops in his understanding of Keller's life and, consequentially, his understanding of the world. He goes from making immature jokes about Keller being a war criminal in hiding, to having a deep respect for his professor and what he has endured. Through knowing Keller, Paul comes to learn more about the cruelties of the world. He also matures in his perspective on his relationship with Keller, realizing more and more the impact Keller has had on his life.