I consider the Exotic an indispensable element of the kind of stories that I am looking for. In a fine post on the subject, Rampant Coyote uses the phrase “lurid spectacle”, which I believe he got from Lester Dent.
To sum up a surprisingly deep concept in as few words as I can manage, the Exotic is That Which Does Not Belong Here. (I am using Here in the sense of “in this story”–frequently it is the setting which is Exotic, so actually it’s the characters who do not belong there.)
The critical linchpin of the Exotic in the sense that I mean it, as opposed to simply being strange for the sake of being strange is that there must be a clear sense that the other things do belong. There has to be an established zeitgeist, characters who are suited to the metaphysic of the story universe, objects that fit into this world, an expected course of events. Without establishing the reader’s understanding of what is right, there is no shock in encountering what is wrong.
The Exotic need not be supernatural or otherwise counterfactual, but it is intrinsically unnatural–that is to say, against the natural order of things. This presupposes a metaphysical authority–which doesn’t mean a theological authority (much less a God), simply a self-evident standard of right and wrong which the protagonist believes and the reader is willing to accept at least for the duration of the story.
Nor is the Exotic necessarily evil in an objective moral sense. It is dangerous, and the intrusion of the unnatural into the character’s world should be the conflict that drives the story, but the Exotic element may be entirely amoral, like a storm or a virus.
This may sound confusing (it’s clearer in my head than the words I’m getting down) so let me try some examples.
The hero is a cab driver. He picks up a woman who has been injured and is being pursued. If her pursuers are ordinary criminals that wouldn’t be Exotic in my sense (criminals are an unpleasant but real part of the natural order). An Exotic pursuer would be outside of the driver’s ordinary frame of reference–a cult that believes the escaping woman to be an alien spy, for example, or the woman’s formerly conjoined twin who wishes to kidnap her sister in order to sow them back together.
The hero is a cop in a small seaside town. During a hurricane he becomes involved in a struggle with criminals. That in itself wouldn’t be Exotic, what would make it so is if they were the descendants of a group of Japanese soldiers who went into hiding during World War Two and are intending to invade the US mainland for the Emperor.
The hero is a private detective investigating the theft of jewelry for an insurance company. He finds that the policyholder faked the theft–not Exotic in itself, but it would become so if the policyholder was hypnotized to steal her own jewelry and give it to the hypnotist.
These are examples just off the top of my head, and I’m still not sure that I have a handle on what I mean. I invite discussion on this topic–that would help me to clarify my thoughts.