How we cite our quotes: (Chapter.Paragraph)
Quote #4
There was not another human being within half a billion miles.
And yet, in one very real sense, he was not alone. Before he could be safe, he must be lonelier still. (28.25)
Hal figures isolation will be safe…and David Bowman comes to the same conclusion. One thing about being isolated, you know no one will kill you. People (or, in this case, computers) are dangerous.
Quote #5
During the last three months, David Bowman had adapted himself so completely to his solitary way of life that he found it hard to remember any other existence. He had passed beyond despair and beyond hope, and had settled down to a largely automatic routine…(33.1)
In isolation, Bowman has become computer-like. It's like he's merged with Hal. Or as if the novel tends to view humans like computers, and enjoys watching them run through routines.
Quote #6
It if had been alive, it would have felt excitement, but such an emotion was wholly beyond its powers…It had waited three million years; it was prepared to wait for eternity. (38.7)
The Star Gate feels nothing—so why imagine it as feeling something? The suggestion is that it's a kind of computer, like Hal, similarly singularly focused on its mission. The purposeful isolation is meant to be eerie and impressive.