Maybe we can find a medium who can channel him for us?
This way we get two guests at once and they can argue amongst themselves...
Dr. Novella: "So how did you get to where you are now?"
Medium: "Me? or the one?"
Dr. Novella: "...uh yes, you."
Medium: "No, I think Dr. Novella was talking to me."
Medium: "Quiet now, let me talk."
Medium: "You're a con artist; i'm not really here anyway Dr. Novella. Please just ignore 'me'."
Medium: "Sorry about that Steve, the unbelieving spirits can be tricky to handle."
Dr Novella: "...?"
Rebecca: "Uhm, this is just strange..."