Ghosts are officially largely ignored in the world of the Beast - of Western power since Roman times. They go beneath the radar of science and official knowledge. Descartes was the philosopher whose ideology ensured this. He put it about successfully that if you cannot find true facts by repeatable experiments they aren't worthy to be regarded as true facts - or at least for geeky people that is how Descartes gets interpreted. Of course knowledge exceeds science and includes humanities so not all are so geeky. Many believe ghosts do exist. So ghosts get ignored when official knowledge excludes experience in preference to experiment but unofficially and in societies not so controlled by Cartesianism (Descartes' followers) but subject to other influences like Locke favouring experience the possibility or fact of ghosts is accepted. Ghosts can be a plague though when the powerful sorcerers of ages past exist as ghosts and wander the Earth and don't easilly get driven away. Jesus took them on though and have His followers power to do the same using their faith and His powerful name for invocation against them.
