So now your saying that ghosts are real. On what grounds though? Maybe you've striked something but what you said doesn't necesseraly mean that it is for real. Maybe, from what you said, the ghosts are simply figments of our imagination when we transition from wake to sleep. Usually when someone says they see a ghost it's when they are either sitting or laying down, watching tv, reading a book or falling asleep. Each way is a good method of going to sleep so maybe they are just overly tired.
But lets say ghosts are real. I still do not believe they can be psychical since they can supposedly pass through walls. Of course there is no proof of such a thing being true since i am taking such ideas out of movies, books etc. But lets say they can pass through walls, that there shows you that it can't be psychical, unless of course the ghost has some kind of trait similar to light. But light also has physical properties in which ghosts do not.
To truly find out the properties of a ghost you need to answer the following questions:
1. Does it emit, reflect or absorb light?
2. Does it pass through walls?
3. What color is this ghost?
4. Is it visible, and when is it usually witnessed?
5. The shape, size and "texture" of the ghost.
6. If the ghost can make sounds, if so what kind of sounds?
etc etc etc.