How we cite our quotes: In consultation with my editor, we decided (against standard practice) to go with page numbers—since The Sunset Limited is one long act and it would be unwieldy and impractical to number all the lines.
Quote #7
WHITE: […] Everything you do closes a door somewhere ahead of you. And finally there is only one door left.
BLACK: That's a dark world, Professor. (131)
White is saying that the longer you live, the fewer escape routes you have from the meaninglessness of it all. At some point, you finally only have one escape route: death.
Quote #8
WHITE: […] Well, here's my news, Reverend. I yearn for the darkness. I pray for the death. Real death. If I thought that in death I would meet the people I've known in life I dont know what I'd do. That would be the ultimate horror. The ultimate despair. If I had to meet my mother again and start all of that all over, only this time without the prospect of death to look forward to? Well. That would be the final nightmare. Kafka on wheels. (135)
White sees any kind of prolonged human interaction as agony. He doesn't want to relate to anyone, or share their pain, not even when it comes to his own mother. His desire is for what he imagines is the perfect isolation of death—perfect because there's not even a person there to be isolated, since that person won't exist anymore.
Quote #9
WHITE: […] You cant be one of the dead because what has no existence can have no community. No community. My heart warms just thinking about it. Silence. Blackness. Aloneness. Peace. And all of it only a heartbeat away. (136)
To get technical, it's debatable whether the annihilation White imagines would really be peaceful. You know, because he won't exist then. In point of fact, it wouldn't be peaceful because it wouldn't be anything at all. For someone who loves logic, it kind of falls apart sometimes when he's waxing romantic about dearh.