Regarding the ghost thing, I assume it wasn't the case here, but it could be a life-or-death situation... see this video (I don't want to spoil it so I won't say more): https://www.ted.com/talks/carrie_poppy_a_scientific_approach...
Edit: added spoiler warning
Edit: I have now added a spoiler warning to my original comment (I hadn't thought about this possibility, sorry)
I habitually avoid videos on the internet, and with the summary, I was able to at least get the gist of the video, whereas otherwise, I would have never watched it.
Even TED talks? :(