How can I write a strong thesis statement for an essay on Cathedral by Raymond Carver? I would like to start off with how judgmental the narrator...

The narrator judges the blind man because he is uncomfortable with having a blind stranger in his home. And since the blind man has a past relationship with is wife, the narrator is also jealous. Note that his wife says that he (the narrator) does not have any friends. The narrator also mentions that he smokes marijuana every night until he can't stay awake and that he and his wife never go to bed at...

The narrator judges the blind man because he is uncomfortable with having a blind stranger in his home. And since the blind man has a past relationship with is wife, the narrator is also jealous. Note that his wife says that he (the narrator) does not have any friends. The narrator also mentions that he smokes marijuana every night until he can't stay awake and that he and his wife never go to bed at the same time. So, we might presume that the narrator is in a rut. When the blind man asks him about spiritual matters, the narrator says he does not believe in anything. There is nothing to indicate what the narrator believes in or what he thinks about life. He expresses a nihilist attitude in this way. 

So, consider this idea that judging a man for an inability to "see" is the narrator's projection about his own inability to see meaning and/or spirituality in his own life.

The narrator mistrusts the blind man. He seems generally uncomfortable about a man who cannot "see" things. However, the narrator does not believe in spirituality and/or religion. He does not believe in what he cannot "see." In closing his eyes and drawing the cathedral with the blind man, they both are able to "see" it. This is a revelation for the narrator. And since the cathedral is a religious symbol, there is a metaphorical indication that the narrator is finally able to "see" (understand) something he cannot actually see. In other words, he gets a taste of what it is like to be blind but he also gets an idea of what it is like to believe in something he can't see. They share a common experience of seeing something without their eyes. For a nihilist and a man who's just lost his wife, drawing the cathedral is, in a way, an exercise in finding meaning, and this meaning is perhaps spiritual.