The afterlife is the realm of thoughts. This Earthly life is as well, but the material world so preoccupies people that they focus on it rather than on their thoughts. Actually, however, in all of humankind on this side of the veil and the other side, thoughts are the basis of existence.
People in the afterlife mature spiritually and go into more enlightened spheres of living solely by changing their thinking. Those people who are earthbound are not able to change their thinking to release themselves from the Earth, so they may wander on it for centuries, unable to communicate but unwilling to change their thinking.
However, people who learn about life, God, compassion, loving, and other people become more spiritually mature and rise into other spheres of existence. They do so because of changes in thought.