I grew up in a family that believed in ghosts. My mother believed in them, my sister often claimed to be harassed by them, and my father - well, he laughed at ghosts but shivered when no one was looking. I, on the other hand, wanted to talk to one.
There are lots of stories about the dead communicating with the living, the bible notwithstanding. Ghosts have been with us (humanity, I mean) since time immemorial, antedating all organized philosophical systems - even Catholic dogma. I suppose you could say that the belief that something of us survives death is one of the oldest philosophies. If nothing else, it is certainly the most persistent. Myself, i think that ghosts are a trick of the mind - some deep corner of our psyche that tries to tell us something using the form and voice that will best grab our attention.
Remember, our minds are complex affairs. There are levels of awareness that we are not attuned to. Like dogs being able to hear sounds in the ultra-frequencies, or sharks being able to detect the bio-electrical fields of other fish, or dolphins being able to paint a sonar-picture of their environment, humans definitely have the potential (at least!) to tune in to the world in extra-sensory ways. The mind, therefore, would be operating on at least two levels: the sensory level where the input is primarily from the five senses; and the the meta-level where the input is extrasensory. I think the sense of being looked at (when you 'feel' someone watching you) or 'women's intuition' are very common examples of the mind operating on the meta-level.
This partitioned mind works like this: the sensory mind allows us to function in our ordinary environment, reacting to normal sensory stimulus, and operating according to strict logical rules; the meta-mind, on the other hand, responds to a whole different set of stimule and operates on totally different rules - analogous to what IQ testers call 'lateral thinking.' These two minds don't always interact, probably because we are so bombarded with ordinary sensory perception that we don't 'hear' the meta-mind.
Sometimes, however, like in emergencies or potentially life-threatening situations, the meta-mind throws an override switch that basically grabs our attention, either pushing the sensory mind into the background, or enhancing it to a fantastic degree, typically with an adrenalin spike thrown into the deal.
Naturally, since this is pretty exhausting physically, the meta-mind probably can't do this alot. So, for other situations less drastic, the meta-mind finds some other way to 'talk' to the sensory mind without panicking it. Enter, GHOSTS.
Ghosts are meta-mind creations that act like messengers: delivering information generated by the meta-mind to the sensory mind in a way that attracts the sensory mind's attention. Sometimes, the messenger will be a departed love one, sometimes it can be something from our worst nightmares. The sensory mind -- not knowing what else to do -- interprets the messenger as a ghost. Now this can either scare you or inspire warm and fuzzy feelings of nostalgia or 'ay! naalala nya ako!' The bottom line is that the message was sent and, with any luck, understood.
So, maybe, the chance to ‘communicate with the dearly departed’ is not really something to be afraid of, but something to be welcomed as link between the world we are aware of and an inner awareness that isn’t cluttered by the world. God knows that with all the crap going on in our daily lives, we all need to be reminded that some things are just as important -- like keeping in touch with old friends or family, or forgiving someone for whatever wrong they did you, or just being thankful that you're alive.