I've read through
this story about the ghosts that haunt the survivors of the Fukushima tsunami and reactor shutdown. It seems a genuine reaction to terrible loss on a (thankfully) rare scale.
It is beautiful, and sad, and makes you think of how people react to grief, in ways they don't even understand. Their unconscious minds are operating at a furious rate even when they're numb and shocked.
The monks' and priests' approach, of allowing people to mourn in acceptable ways, is very thoughtful and shows how they coped with a sudden demand for their spiritual services.
BBC is starting a sort of Five Year Plan of WWI commemmoration, and kicked off with Paxman surveying how WWI changed Britain.
He remarked on the growth of spiritualists and mediums during the war and post-war. People who lost loved ones in the war preferred to commune with the spirits, and joined clubs of them.
Or perhaps not seeing their folks come back, and not knowing the outcome made it harder to cope with (as with in the tsunami - so many people simply disappeared).
Fortunately we don't have to cope with communal mass loss like this very often. But maybe ghosts really do appear when your ancestors are included in your life so fully, and when extended families are the norm.
I'm not convinced that ghosts exist. But I am certain that living people have experiences with their memory of their friends and family members, that are utterly real, and meaningful. There are just too many accounts of them, in all cultures, for them to be ignored - they must be an artifact of how our brains work.