When Travelers leave their bodies and attempt to enter one of the Realms, they must first encounter the four barriers. Both the barriers and the realms are best described as alternative worlds—separate from our reality, but still connected to it. None of the four barriers are inhabited and all of them must be overcome in order to reach other realms. The four barriers consist of: 

1. A world with no vegetation

2. A vast ocean 

3. A sky

4. And a world that perpetually burns down—only to reconstitute itself and burn again. 

Once a Traveler finds the “passageway” out of a particular barrier, he/she can instantly pass through again on future journeys. 

In 500 B.C., the Greek philosopher Empedocles stated that the world was made up four elements—earth, water, air, and fire. A generation later, Aristotle took this idea and used it to create a system of natural philosophy. He believed that matter was a blend of the four elements and that an imbalance caused both chemical reactions and illness.

Recent archaeological excavations in Sicily have revealed that Empedocles was a seer and prophet who had a large group of followers. It seems clear that he was a Traveler who encountered the four barriers and used this experience to create a theory of existence.