What details in Cathedral make clear of the narrator's attitude

The narrator's attitude does shift from beginning to the end of the story. In the beginning he narrator is detached from his life. He has issues with himself, his marriage, and his wife's relationship with Robert. What Robert sees and teaches the narrator is to see this transcendent reality. Robert senses a depth in reality that confuses the narrator. Even before they sit together to draw the cathedral, Robert has begun to affect the narrator. It's nothing particular, he says, but nevertheless the narrator finds himself realizing that he does enjoy company, and then feeling compelled to explore the limits of Robert's sight, and to help the blind man visualize a cathedral.