We all have a very clear idea of what a ghost looks like: a pale apparition that looks something like old man Wilkins from the fairground with a sheet draped over his head. But this description rarely if ever fits what is experienced in claimed paranormal encounters. What exactly do we mean when we talk about ghosts?
The most common understanding is that they are phantoms or visions of dead people glimpsed by the living. This is often understood to present some kind of afterlife, some way in which human consciousness or presence can persist after death. On the other hand it may instead suggest that there is communication not across the boundary of life and death but rather across time, that it is possible for those in the present to get a glimpse of some moment in the past, or vice versa. Certainly stories in which are visited by phantoms of the living, visions of relatives and friends in moments of distress or danger, suggest that such communication might be possible across space, if not time.
Some of these ideas might be related to current evolving theories of the quantum brain and the implicatons of quantum physics when applied to consciousness. There is even some implication that consciousness may persist beyond the physical brain, providing another possible explanation for life after death.
Quantum physics also implies the many worlds theory of multiple universes, splintering off at each moment of subatomic decision. Rather than glimpses of the past, could what we call hauntings be glimpses of another, alternate universe alongside our own?
Equally the multiple dimensions that apparently comprise our own universe culd provide yet another explanation: what might a fifth dimensional event look like to us – could it have a side-effect on the fabric of space time that might look like a haunting to us, down here in our three dimensions? Could these phenomena even be attempts at cross-dimensional communication?
Of course, traditional religion and ancient cultures might suggest that they are communication from a very different kind of being: from spirits or what the monotheisms might call demons. But the answer might equally lie closer to home. It has been suggested that it may be that some places have a unique sensitivity. That a place may be able to ‘record’ the events that take place there, ‘recordings’ that will then replay to human witnesses under the right conditions, as ghosts.
And even more simply it may just be that some places are intrinsically ‘haunted’, that they have some property, a peculiarity of electro-magnetic field, or subterreanean running water or a particular geography, that has an effect on the human mind, that affects our senses in away that we call ghostly.
What remains is that many of these possible explanations are open to scientific enquiry that might one day be able to answer the question: ‘What is a ghost?’