Thesis statement for position paper!

During the tutorial session with Mr. Omid, he had explained to us on what thesis statements was about and what was the criteria of a good thesis statements. According to him, our thesis statements need to be argumentative, specific and based on our personal views of the texts. We can either do our position paper based on poetry texts, short stories, novels or plays. My first thesis statement was based on the short novel, "The pearl" by John Seinbeck. I chose to talk about the evilness of the pearl that had caused the downfall of Kino's life. However, when my other classmates were presenting their thesis statements and based on the comments given by Mr.Omid, my thesis statement will definitely be rejected as the idea was already mentioned by the author so it was not really my idea. So I was like, "Arg..god help me to think of one thesis statement" Furthermore, the facts that most of my friends had already come out with their thesis statements and Mr Omid had already approved them made me even more stressful and worried. I must come out with a brilliant thesis statement soon!!!!