While hunting for a criminal who is good at hiding his face, Don asks Charlie to see which crime syndicates their suspect may be a part of. To figure it out, Charlie explains the belief propogation which takes scattered data and pulls it into a coherent image.
The company has a discussion on ethical dilemmas involving stealing in a perilous situation. They then shift into a philosophical discussion when Andy asks Michael how he knows the wall in the room is there if he's not looking at it. Michael goes into a deeper philosophical discussion by questioning the knowledge of other people and objects.