You may not know that Game of Thrones scribe George R.R. Martin wrote short stories back into the early 70s, and one of them, "A Song for Lya," won the Hugo award for Best Novella in 1975. I see it online here or get a Kindle version for a couple of bucks.
The story has to do with our essential, existential isolation as referred to in the Wittgenstein episode. It's about a husband-wife couple who are psychics of various sorts and so can overcome (for brief periods, at least) some of the isolation that they pityingly describe the rest of us as stuck in. They're put on assignment to investigate an alien race where every one of them allows a parasite to kill and eat them when they hit age 40. Well, it turns out that this parasite enables a sort of group mind, allowing an everlasting unity and bliss much more profound than even the psychics can have with each other, such that turning oneself over to the parasite may be rational: it may fulfill the goal of all human religious endeavor, which is to get rid of this existential aloneness.
So, it's a pretty thought-provoking, interestingly written story, though on the depressing side (and, as I experienced the audio version,hearing the male narrator gush on and on in the female psychic Lyanna's voice about love and oneness was a bit much for me). It raises one of the usual kinds of objections to utilitarianism and other theories of value: "Look! Here's what your value system should applaud! Yet letting your brain get eaten by alien fungus is gross! You'd better rethink things!"
Specifically, it challenges those that characterize us as fundamentally oriented to need God or seek after oneness out of existential angst; Martin opines that for humans, yes, that's an urge, but we also have this opposing urge in favor of self-assertion and pushing others away. Maybe, as Freud thought, our innate desires are really contradictory such that happiness of the sort we'd dream about simply isn't an option; the best we can hope for is some degree of satisfaction and sublimation of the rest.
It did occur to me that Martin's model of the psyche, where we all have these uncounted layers such that even a psychic couldn't penetrate all of them, maybe be faulty. I think one of Wittgenstein's points is that we're just not in a position to say whether there are such parts of ourselves that are in principle not available to anyone else. It's not like all this stuff is going on that a psychic (if there were such a thing) could then open up and look at, but rather that it's the exposure and potential exposure to the public (i.e. I could say something I'm thinking) that makes something a thought in the way we understand it. I'm still not sure how I feel about that.