David Ketterer

If, at its most exalted level, apocalyptic literature is religious,
the concerns of such a literature, at its most popular level, find
expression in the gothic mode and especially in science fiction.
Clearly, the introduction of the other, the _outré_, whether in
terms of supernatural manifestations or creatures from outer space, is
going to upset man's conception of his own situation and prompt him to
relate his existence to a broader framework. It is the particular
function of all worthwhile science fiction to explore the philosophic
consequences of any radical disorientation.