Many years ago, I watched a chat on tv of Jack Nicholson telling of his somewhat weird telephone calls with Harry Dean Stanton. The calls were often late at night and lasted for maybe an hour or two. Now what impressed me the most was that the calls were not constant talking. He said that they were not scared of silence or what tv people call dead air. They often went many minutes without either of them saying a thing. I would love if I could do that, but I can't. So after watching the movie, I think Jack was talking to Lucky and imagine that much of the dialogue was very near the dialogue between Jack and Harry. If you were paying attention, the character Lucky picks up the phone late at night and calls an unidentified person and shares a new take on his discovery of the moment. That was Jack on the other end of the line.