Before you can open the can of worms that is “ghosts” which would imply life after death and the existence of souls or spirits one would have to refute a variety of much simpler explanations for these reports such as normal and admittedly confusing and frightening waking/dream states, hallucinations caused by drugs, mental illness, brain damage, poisons, etc., and simply people lying for attention.

Unless there is real evidence of something unknown to science, for which scientists would be beating down your door to examine because it would make their career, then you have no reason to call anything a ghost and to do so would be intellectually dishonest given the examples of actual phenomenon that I just mentioned that explain everything about ghosts without requiring ghosts.

You can read more about the common explanations for the erroneously assumed supernatural in Carl Sagan’s book “The Demon-Haunted World: Science as a Candle in the Dark” http://www.amazon.com/gp/product/0345409469?ie=UTF8&tag=yahans01-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=0345409469“

Ghosts are not real. People lie for attention and there eye witnesses are either fulled by a trick or there in on it.

Choose NM’s answer. He/she is absolutely correct, and I also implore you to read “Demon Haunted World”- it will give you even more information on this topic.