I’m curious what the context of that sentence is. There’s a tragic irony to being unable to believe in a philosophy that assigns meaning to life when you hate life.
The context is that his neighbor, who is the only person in real life who treats him kindly, believes in God. The speech is him telling the reader that he doesn’t have the heart to tell her that God is a myth perpetuated for generations and that he’s so much better off. And it’s at least a couple paragraphs long, just ranting to the reader about how enlightened he is and how dumb his kind neighbor is.