I've seen/heard enough things dead sober that I am convinced that ghosts exist, in one format or another. It may not be what we think, though, typically as ghosts. It could perhaps be some sort of quantum imprint. I'm open to a variety of possible causes and explanations - none of which are necessarily mutually exclusive - but I don't think there's any question that what we know as ghosts in terms of the associated manifestations are real.
Any place with a great deal of history, particularly castles, dungeons, etc. seems to have this type of thing go on, where perfectly boring, sober, intelligent, skeptical people witness ghosts all the time. I don't think it matters much whether or not the Sabbath guys were sober or not at the time, I'm sure they saw what they saw, it's commonplace.
