Normally, the characteristics of something tells us what it is. Does this help explain what are ghosts? Let's take a look
Anatomy of a ghost
Ghosts can appear solid or like a mist. They can be transparent or opaque. They can appear to be totally unaware of our presence or they can interact with us. They may be recognisable as to whom they were in life or they can be totally unknown. They may appear at a particular time and / or date to a particular sort of person such as a child or female, or they may appear any time to anyone. They may appear to be human or animal or even a mode of transport. They may make us feel calm or they may frighten us. And they can be experienced by any of the five senses with the exception of taste. A ghost may also be sensed rather than seen. A ghost may be visible to one person and totally invisible to another person standing beside the observer. So the characteristics of a phantom just seems to tell us that a ghost can appear in many different guises.
So what are ghosts according to some popular theories?
Are ghosts demons?
Some religious people will tell you that ghosts are 'demons' or 'fallen angels' who's purpose is to keep you from God! The argument is that the dead are either, 'at rest' awaiting 'Final Judgement', or have gone to Heaven or the other place. So, according to this theory, as ghosts cannot be the spirits of the dead then they must be demons.
Are ghosts souls that are 'stuck'?
There are those who believe that a ghost is the spirit of a person who has died but who is unable to, 'move into the light', for some reason. Perhaps they have had an addiction that they continue to try and 'feed' in death. So, for example, they may hang around bars or brothels that they frequented in life. Or maybe they feel guilt for some crime they have committed and they are afraid that they will be judged and found guilty and spend eternity in Hell. This, I believe is one answer to the question, 'what are ghosts'
Can ghosts be residual hauntings?
This idea was popularised as the 'Stone Tape Theory', which states that an event of an emotional nature can be somehow recorded in the fabric of a building or object or in rocks and this is then 'played back' to anyone who is sensitive. Rather like a video tape. I personally believe that many ghosts, such as the Roman ghosts of York are of this nature. However, a recording is always the same, it never changes. if the actions of a ghost change or if it interacts with those who see it then it cannot possibly be a recording.
Are ghosts lost spirits?
When Ghost hunter, the late Hans Holzer was asked during an interview, 'What are ghosts?', he answered, 'A ghost is a human being who has passed out of the physical body, usually in a traumatic state and is not aware of his true condition'. This may explain some appearances but for example, what are ghosts of those who have had their head chopped off. I cannot believe that they are unaware that they are dead? And what is a ghost that appears not as human but as the phantom of an animal. No, this certainly is not the complete answer.
Are ghosts an illusion?
Some people, who do not believe in ghosts, think that they are misinterpretations of natural phenomena. Having seen a tree in a local cemetery give off a great cloud of pollen that looked suspiciously like some pictures I have seen of 'ghosts', I can understand this idea.
Indeed, it has been proved that, in certain situations infrasound and strong magnetic fields can make a person feel that they are in the presence of the supernatural. However, this explanation does not explain how several people can see and describe exactly the same phantom at different times or ghosts that give a message.
Are ghosts created by the mind?
There are those who think that some ghosts are a thought-form. Indeed, strong enough thought, either of an individual or a group, can under certain situations, create what appears to be a physical form. The explorer Alexandra David-Neel relates how, by sustained concentration, she was able to create the image of a jolly, fat monk that was visible, not only to herself but others in her party as well.
Perhaps, thought-forms could explain phenomena such as the reoccurring battle of Edgehill where the 'ghost' of those who survived appeared alongside that of those who died.
Conclusion?
So, have we answered the question, what are ghosts? Well no, not really. I think that this is because we are considering several different phenomena that we lump together under the title 'ghost'.