based on an ancient Tibetan buddhist practice called Chod. It's a great book for anyone who wants to work with inner voices, archetypes, etc. Your friend sounds very creative. If he has aspergers then this is probably part of his personality that he may have developed as a way of coping with his isolation and some early trauma related to dealing with an alien world. It's probably hard to let go of such imaginary friends given they are such a strong part of his personality. It's a point of reference that he can return to when life becomes uncertain. There are a few different perspectives on reality. There is the physical reality. Without getting into philosophy too much, this is the straightforward idea that there are things, objects if you like, and we interact with them physically. Our bodies are part of this physical reality. Our brains, responsible (among other things) for making sense out of information our senses collect, throw away and manipulate a lot of that information so that we don't go insane from perpetual information overload. Therefore, we have an internal "psychological reality" that is not an exact representation of the physical reality. Our thoughts, beliefs, values and generally all kinds of mental patterns and habits arise out of this psychological reality. All the things that go through your psychological reality eventually crystallize into what we might call a "symbolic reality" ? in this, we attribute meanings to things we have observed and connect things together and