Is it possible that ghosts and spirits exist and would there be a scientific explaination for that?

Question: Is it possible that ghosts and spirits exist and would there be a scientific explaination for that?
- Keywords:
  ghost,
  scientific,
  spirit
Asked by libslytherin to Mike, Pip, Tianfu, Tim, Tom on 29 Jun 2012.
- Tom Lister answered on 29 Jun 2012:
  
  It is possible, but I don’t think they exist. If they did exist, there would be a scientific explanation (we would just have to think of one).
- Tim Stephens answered on 30 Jun 2012:
  
  I don’t believe in those kind of things. They may exist, but I don’t believe that there’s been any evidence of them found yet.

Question: Is it possible that ghosts and spirits exist and would there be a scientific explaination for that?