Provide the theme summaries for the following conversation: 

Peter: I don’t believe in the afterlife but I’m happy to be convinced. Let’s agree on a code word now so whoever goes first can make contact and, importantly, authenticate themselves. Something a charlatan medium would never guess? I suggest ‘full bush’?
Linda: Why full bush?
Peter: Why not?
Linda: Ok, I'm in. But you know this has been done before right?
Peter: What do you mean?
Linda: Houdini. He promised if there was an afterlife, he'd find a way to send a message. If anyone was going to come back it was him
Peter: Everyone's a critic

Summary: 
Peter doesn't believe in the afterlife but he's happy to be convinced. Linda and Peter agree on a code so whoever goes first can contact the other one.