An expression used in the book Stranger in a Strange Land by Robert Heinlein. It means “to understand so thoroughly that the observer becomes a part of the observed—to merge, blend, intermarry, lose identity in group experience. It means almost everything that we mean by religion, philosophy, and science—and it means as little to us (because of our Earthly assumptions) as color means to a blind man.” It is a popular term used by the Church of All Worlds meaning to understand something completely and absolutely.