Paranoia, in some respects, I think, is a modern-day development of an ancient, archaic sense that animals still have-quarry-type animals-that they're being watched .... I say paranoia is an atavistic sense. It's a lingering sense, that we had long ago, when we were - our ancestors were - very vulnerable to predators, and this sense tells them they're being watched. And they're being watched probably by something that's going to get them ....
And often my characters have this feeling.
But what really I've done is, I have atavised their society. That although it's set in the future, in many ways they're living-there is a retrogressive quality in their lives, you know? They're living like our ancestors did. I mean, the hardware is in the future, the scenery's in the future, but the situations are really from the past.
- Philip K. Dick in an interview, 1974.