If we recognize that the soul is separate from the physical body, and that there are also vital and mental sheaths that are independent of the physical body, the question arises as to what happens to the soul upon dissolution of its tie to the physical body. It is a common experience and built into our language “the soul departed….” to describe death. People throughout time from different cultures around the world have developed their own explanations for the location of the soul after death. Whether we look at the Tibetan Book of the Dead, which describes an intermediate location called the “bardo”, or the ancient Greek concept of the soul going into the “underworld” there to reside, based on various criteria, or to be washed in the waters of lethe (the river that eliminates past life memories) in preparation for returning to birth, we see the concept enunciated that the soul can go somewhere else, reside independent of the body for a time, and then prepare and return to a new birth in a new body.
Despite the signature strength of the mental development in Man, it would not be likely that the soul would reside in a mental world or plane, as it is separate from the mental being, as well as the vital being that it forms for its own evolutionary purposes.
Sri Aurobindo provides some guidance on the issue of how the soul’s location and focus is to be understood in the post-death environment: “For the post-mortal state of the soul must correspond in some way to the development of the being on earth, since this after-life is not a free upward return from a temporary downward deviation into mortality, but a normal recurrent circumstance which intervenes to help out the process of a difficult spiritual evolution in the physical existence. There is a relation which the human being in his evolution on earth develops with higher planes of existence, and that must have a predominant effect on his internatal dwelling in these planes; it must determine his direction after death and determine too the place, period and character of his self-experience there.”
Clearly the impulsion of the karmic forces at work through the life of the individual will provide the determining direction and focus for the next steps of the soul’s evolutionary path through time.
Sri Aurobindo, The Life Divine, Book 2, Part 2, Chapter 22, Rebirth and Other Worlds; Karma, the Soul and Immortality