That's ridiculousness. When I see an apparition I will believe there is something that needs further investigation. How do you get from seeing something to dead people haunt the living. Its an absurd leap. There are a whole host of things you would have to rule out first. I would sooner believe it was a gaseous alien than a ghost. That's like saying when you see Pen and Teller live in Vegas you will believe in magic. Why would I jump to the supernatural when I haven't bothered to rule out the natural.