Death is a very controversial topic the moment you begin to ask if there is anything after the physical self is no longer working. Science does not permit the notion of ghosts, stating that despite numerous claims there is no evidence that conclusive proves their existence. People who believe in the soul or spirit claim that it is quite likely that some spirits get stuck in a go-between situation that is neither here nor there and all this is bolstered by the endless accounts of haunting and strange pictures and phenomenon that keep some people quite serious about ghosts.
The most basic feeling of ghosts is the sensation that people often perceive that they are no longer alone. Occasionally, people also report that this not quite lack of company is seen as an apparition.
There are two theories here. One suggests that the human mind if quite capable of fooling itself into seeing things. The other suggests that the human mind is powerful enough to glimpse into the other world. This mental aspect gets more complicated through scientific demonstrations that clear show that people who have gone through severe trauma, especially involving death or prolonged suffering, will often suffer from delusions that will make them see the dead. In many cases, the witness to these apparitions will keep seeing reruns of the same tragedy every time they cross the place where it occurred. Theologists have coined a phrase for this and it is "energy of history".
In 1911, Dr. Sharon Gill and Dr. Dave Oester formed the International Society of Ghost Hunters with a view to finding evidence of ghosts. Since then the society has published many accounts of reported haunting.
Those who believe in ghosts say that these are spirits who are unable to leave our world due to several reasons like unfulfilled desires, unexpected death, or simply a deep attachment with some other humans. Such spirits roam around us as ghosts. This is supportive of people who have been claiming to communicate with the dead loved ones and most religions in existence today include the concept of an immortal soul that is supposed to leave our bodies after physical death and that provides plenty of scope for the presence of ghosts.
While there is no scientific evidence of any kind of existence post-death, this has not prevented the constant emergence of haunting tales across all cultures in the world. A haunting typically takes place in old homes or places where death was traumatic.
A simple way of defining a ghost would be the spirit of a human being that continues to dwell on this planet after the body is dead. Interestingly, this notion is common throughout the world regardless of religious and cultural differences. Another common aspect is the belief that these spirits are lost and probably unaware that their bodies are dead so they stay close to what was familiar to them in their lifetimes.
Ghosts do not have any physical bodies and so they are often foggy or misty shapes, or even translucent. They are felt through their actions rather than physical presence.