Suppose you are a parapsychologist and you decide to create an imaginary ghost, which will help prove your theory that "ghosts" are really some kind of psychokinetic Jungian construct, put together by a collective unconscious? Now, further suppose that you succeed in your experiment and this ghost seems to start acting of its own accord. Does this make the ghost real or a construct of its creators?
This is the basic hypothesis of David Ambrose's "Superstition", and the horrors that follow are based on the struggle between the wills of the group that created an imaginary ghost, and the will of the imaginary ghost that seems to think that he is real. As one of the characters observes, this leads to certain "incompatibilities" which, somehow, have to be resolved. Either the ghost must die, or its creators must.
Readers of this book who know their SF will be irresistibly reminded of Ursula Le Guin's "Lathe of Heaven" rather than the more obvious candidate when it comes to shifting perceptions of reality -- Philip K Dick. There is, though, one moment that also has echoes of an incident in "The Man In The High Castle".
Superstition is more, therefore, than your average UK horror shocker involving the supernatural. It poses fundamental questions about the natures of reality and time, of cause and effect. And, in a fashion, it comes up with possible answers. Ambrose can also write with admirable fluidity, which made this an easy book to read in a day and a hard one to put down without doing so.
Notwithstanding this, most of the characters come across as channels for the plot rather than individuals in their own right. We have the stereotypical rich philanthropist, sleight-of-hand "mediums", love affair between the two leading characters, and so on. None of them ever really jump off the page and have the reader saying "Yes, I know this person, they seem real to me".
Curiously, the most real character is the imaginary ghost. Was this perhaps deliberate on Ambrose's part, or am I giving him too much credit?