Do Catholics believe in ghosts? Absolutely! Ghosts, defined as disembodied, human spirits (as opposed to angels), are one of the ways we know about purgatory (though it is also revealed by God). Jacobus de Voragine’s Golden Legend, coming out of the great thirteenth century, became one of the most popular books of the Middle Ages. You can think of it as an earlier version of Butler’s Lives of the Saints. We tend to think of a legend as something fictitious, but legenda simply meant something to be read. Some do accuse Voragine, however, of indulging in things we would consider legendary (which may have contributed to the modern meaning of the word). …

http://www.ncregister.com/blog/staudt/eyewitness-accounts-of-encounters-with-ghosts-from-purgatory1