In Ian McEwan's novel "Sweet Tooth," the author emphasizes the importance of a strong bond between the writer and the reader. He suggests that there exists an unwritten agreement where the writer must maintain the integrity of the fictional world and its characters, ensuring they are consistent and believable. This commitment to coherence is crucial for fostering trust with the audience.

McEwan argues that every element of the story must be as authentic as real life, and authors should avoid altering the narrative capriciously. This dedication to creating a solid and reliable universe allows readers to become fully immersed, reinforcing the mutual reliance that characterizes the reading experience.