Physicist Tom Campbell spoke about his experiences exploring different realms of consciousness. He worked with Robert Monroe in the early 1970s, helping establish Monroe's laboratory for the study of consciousness, and develop the Hemi-Sync technology, used to attain specific altered states.
Learning to have out-of-body experiences (OBEs) was the doorway that led Campbell to further explorations into non-physical realms. The non-physical realms have greater variety and fewer constraints than the physical world we are familiar with, he explained. He has made trips to the probable future, and said that humanity still exists a thousand years from now.
Beliefs and expectations surrounding the out-of-body experience can hold people back, he said, adding that the mind's intent can be a powerful tool for moving into non-physical realms. In his book series, 'My Big TOE,' TOE is an acronym for "Theory of Everything," and he uses his knowledge gleaned from the non-physical realms to expound on life, purpose, physics and evolution.