According to certain schools of yogic philosophy, Self-realization is achieved when a yogi transcends the three realms of existence. These are the material world, the astral world and, finally, the causal world. The causal world is the realm beyond the material and astral worlds. It is the world of thoughts and ideation, where consciousness resides once it has transcended the other two.
Once a yogi’s consciousness enters the causal world, they have no need for a gross physical body and become beings of pure light. They have understood that both the physical and astral worlds are simply manifestations of thoughts within the causal world. It is said that someone who has entered the causal world can use their thoughts to do anything someone in the physical world can do. They are only limited by thought itself.