How does Robert help us to understand Bub in "Cathedral"?
The narrator of this short story by Carver is presented as a character who is extremely isolated. Even though he is married, it is acknowledged that this marriage is under strain and he is unable to openly and honestly express himself and how he feels to his wife. What is fascinating about the character of Robert, however, is that he helps those around him to see themselves better and to grow in self-knowledge--something that is ironic given his own blindness. He has already done this with the narrator's wife through their earlier friendship together, and in the course of this short story he does it with Robert. Note how his request that the narrator draws a cathedral with Robert's hand on top of his triggers an epiphany in the reader:
So we kept on with it. His fingers rode my fingers as my hand went over the paper. It was like nothing else in my life up to now.
Robert encourages the narrator to engage in a creative activity, and as a result causes the narrator to experience an epiphany that allows him to truly "see" himself for who he is. The value of Robert therefore is as a kind of catalyst in terms of the impact he has on those characters around him. He helps the reader understand that the narrator is a very isolated individual lacking in self-knowledge, and he challenges this state by helping move the narrator on in his understanding of himself and life.