I've got this theory.
Some people say they've seen apparitions in clothes from long ago and they'll say they walked through walls etc. My theory is that what they see is some sort of time-slip; not the spirit of a dead person but a sort of photographic image of a moment in time past, superimposed on the present. A case in point is the Romans at York. Several visitors to the museum are said to have seen Roman soldiers marching along in the basement but all, sort of, cut off at the knees. They've found out that the original Roman road was about 2 feet lower than the floor of the basement that's built on it, so they're marching on the road and you can't see their feet.
Doesn't explain my disappearing lady in the church though.
