Ideas about death, souls and afterlife existence are often intertwined with religious or spiritual beliefs—in other words, belief in the supernatural. But are spiritual forces present or observable in this world? Do they exist? Can they be observed, defined, categorised? Are friendly ghosts and vengeful spirits lingering in haunted houses real, are the paranormal investigators you see on television really fighting an evil spirit as they claim, or are all these ghost sightings a hoax that can be disproven with scientific evidence?