Matter-of-fact
Do Androids Dream of Electric Sheep? takes place in a future where mankind lives among the stars, spread out across the vast, unknown landscapes of extraterrestrial planets. But the tone of the novel is very down-to-earth. The omniscient narrator discusses the weird happenings of Mercerism and renegade androids as though he were chatting it up with us over a cup of coffee. You know, just another day, after work, talking about humanoid constructs hiding among the people of Earth. NBD.
The character's dialogue also feels like real people speaking—even when they aren't technically people or, for that matter, real.
Chew this example over:
"You're not Polokov, you're Kadalyi," Rick said.
"Don't you mean that the other way around? You're a bit confused."
"I mean you're Polokov, the android; you're not from the Soviet Police." Rick, with his toe, pressed the emergency button on the floor of his car. (8.72-74)
Now, Dick's novel didn't need to add Rick's flub. From the technical perspective of storytelling, it doesn't alter the plot at all, since it doesn't not affect the outcome of Polokov's scuffle with Rick. But the flub makes Rick pop off the page, all the more human. We've all had those moments, haven't we?
It's these small details—whether provided by the narrator or the characters—that provide the story's tone with an everyday quality. Truly the novel is just another day in the future.