Final answer:
The quote can be found on page 146 of "Turtles All the Way Down" by John Green, and it reflects the idea that thoughts are separate from one's true self.
Step-by-step explanation:
The quote "Thoughts are only thoughts. They are not you, you belong to yourself even when your thoughts don't." can be found on page 146 of the novel "Turtles All the Way Down" by John Green. In this novel, the main character, Aza, struggles with intrusive thoughts and anxiety, and this quote reflects her realization that thoughts are separate from one's true self. It emphasizes the idea that even when our thoughts may not accurately represent who we are, we still have control over our own identity.