Toward the end of the story "Cathedral," the blind man asks the narrator to describe a cathedral. Why is the narrator unable to do so? What does his inability to do so reveal about himself?

At the end of the story "Cathedral" by Raymond Carver, the narrator is sitting with Robert, who is blind. They are watching TV together, and a program comes on which focuses on cathedrals. Suddenly, the protagonist (who is not given a name) asks Robert,

Something has occurred to me. Do you have any idea what a cathedral is? What they look like, that is? Do you follow me? If somebody says cathedral to you, do you have any notion what they’re talking about? Do you know the difference between that and a Baptist church, say?

He suddenly realizes that Robert's view of the world is generally limited to what other people tell him. Robert explains,

"I know they took hundreds of workers fifty or a hundred years to build," he said. "I just heard the man say that, of course. I know generations of the same families worked on a cathedral. I heard him say that, too."

Then, he admits that his understanding of cathedrals is very limited, and he asks the protagonist to describe a cathedral to him. The protagonist realizes how incapable he is of putting his ideas into words:

I stared hard at the shot of the cathedral on the TV. How could I even begin to describe it? . . . I stared some more at the cathedral before the picture flipped off into the countryside. There was no use.

No matter how hard he tries, he cannot put the idea of a cathedral into words. As he continues to wonder why he cannot put it into words, he explains:

"You’ll have to forgive me," I said. "But I can’t tell you what a cathedral looks like. It just isn’t in me to do it. I can’t do any more than I’ve done." The blind man sat very still, his head down, as he listened to me. I said, "The truth is, cathedrals don’t mean anything special to me. Nothing. Cathedrals. They’re something to look at on late-night TV. That’s all they are.”

Robert then asks the protagonist to draw a cathedral with him to give him a better idea of what a cathedral looks like. Though the protagonist does not understand why they are doing this together, Robert reassures him:

"Go ahead, bub, draw," he said. "Draw. You’ll see. I’ll follow along with you. It’ll be okay. Just begin now like I’m telling you. You’ll see. Draw," the blind man said.

Ironically, the blind man tells the man with sight that he will come to "see" (understand).
The story ends with the reader unsure if the protagonist ever truly gains anything from this experience. Different readers can come to different conclusions. I would suggest that the narrator is reminded of how little he sees and understands of the world and that he is reminded of his own figurative blindness. He also comes to realize that he cares about very little in his life. (This was the reason that he gave for being unable to describe the cathedrals; he did not care about them.) Robert asks him to close his eyes as they finish drawing:

"Close your eyes now," the blind man said to me. I did it. I closed them just like he said. "Are they closed?" he said. "Don’t fudge." "They’re closed," I said. "Keep them that way," he said. He said, "Don’t stop now. Draw." 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.

It is when the protagonist closes his eyes and becomes momentarily blind that he starts to see and understand Robert; he begins to empathize with the blind man and seems to grow in his desire to get to know him.