"There are a lot of things that humans can't explain but that doesn't mean that they're supernatural," he said. "Something I can't explain doesn't necessarily equal ghost."
Sometimes it's simply more work and investigation that separates the explained from the unexplained, he added.
"It's not that things that are explainable are of a different category, it's just something someone has put more time and research into it," he said.
And ghosts, Radford pointed out, are far more deep-seeded that other kinds of paranormal phenomena.
"Ghosts are wrapped up in a religious world view," he said. "Virtually every culture has a belief in ghosts."
Though the ghosts of movies and television shows are often frightening goblins or chilling demons, Radford said that for many ghosts are dead loved ones or spirit guides. As long as people believe in an after-life, there's room for a belief in ghosts.
So what of the reports of ghosts haunting the house of Mark Twain, who himself was thought to be interested in the spiritual movement and the stuff of séances? What of claims that Twain's daughter Susy, who died in the house at age 24, continues to roam the halls?
In September, Hawes and Wilson traveled to the historic home to investigate the reports from Scappaticci, other staff and visitors. They unloaded their technology and spent about a week trying to explore the claims.
And what did they find?
Well... they couldn't quite say.
Though they may be able to stretch the laws of reality, they're still beholden to the laws of reality television.
Hawes said their findings won't be revealed until the episode airs later in the season. But, he teased, "there's just a lot of great stuff coming out... People will be really happy."