Rav Aryeh Handler has a beautiful take on a chassidic story:
Rabbi Issachar of Welboraz was visited by the soul of a dead man whom he ad known before as an honorable man. When the soul came, it asked Rav Issachar for help - his wife has died and he needs money in order to remarry. The Tzaddik asked him: "Do you not know that you are no longer alive - rather you are wandering in the world of Tohu [עולם התוהו]?" When the should did not believe the Rebbe, he lived the coat of the dead man and showed him that he is wearing burial shrouds. When the soul went away, Rav Issachar's son asked: "If this is so, perhaps I am also in the world of Tohu?" His father answered: "If one is aware that there is a world of Tohu, then they can never be wondering in it."
This story has two levels. The first is the surface level. We have a man who has died but thinks he is still alive. He is looking for financial help so he can wed a wife. The desire to marry is really the strongest expression of our desire to be bound. The bond of marriage with a woman, flesh and blood, can give purpose to the connection of the dead to the world of the living. The dead man is trying to anchor himself to a world to which he really has no connection.
The Tzaddik tries to place the dead man in his proper place. He explains to him that he is no longer living. The sense of life that he has is counterfeit. As proof, he exposes to the dead man the shrouds he is wearing. The dead man sees, and as it seems, understands and departs.
Here, however, starts the second level of the story. The Rebbe explains to the dead man not only that he is dead but that he is wondering in the "world of Tohu." In this second layer of the story, this "world of Tohu" becomes a topic that disturbs the Rebbe's son.
The dead man is convinced that he is alive, but in reality he is wondering in the world of the abyss, תוהו:
בראשית ברא אלקים את השמים ואת הארץ והארץ היתה תוהו ובוהו
In the beginning God created the heaven and the earth. Now the earth was unformed and void
The commentators explain the two terms of Tohu and Bohu in the following manner: The world before creation was in a state of Tohu, nothingness. It was empty of anything. It had no point to which one could relate - no good content. The whole essence of the "world of Tohu" is the emptiness. After this stage, came the turn of the built world. Into the emptiness of the world came the content of all existence. Thus its name, Bohu - that is to say Bo Hu. Bo - in it - exists all of reality. The story takes this term which is applicable to the creation of the world and applies it to the state of man's soul. There are people who live in the world of Tohu. They have no ability to connect to reality. They have no ambition in any direction. Inner emptiness encompasses them.
The dead man who comes to Rav Issachar is not necessarily actually dead. He is a character from the world of Tohu. His inner world has become empty. He lost his anchor in reality. This individual is asking for help in clinging to reality - to marry a woman. In truth, however, marriage will accomplish a thing if the person himself is empty inside. His life has no meaning. He has no ambitions and is disconnected.
Rav Issachar explains to this "dead man" that his real problem is the inner emptiness. That he is empty to the point that he is not even aware of his emptiness. He thinks he is still alive but has no critical tools with which to relate to his self. He must be shown his shrouds in order to prove to him his disconnect from reality.
When Rav Issachar's son sees the "dead man" and his condition, he begins to fear that he might also be in the same place but is not aware just as the dead man was not aware. His father's answer is what bring him back his confidence: someone who knows that emptiness exists does not become empty. The whole structure of the world is based on the contradiction between Tohu and Bohu. Only through sensing the emptiness and the lacking can we appreciate the significance of existence and reality.
A person who is aware of the "existence" of Tohu. Who understands the significance of Tohu. He knows that the Tohu might be in his soul - but through his fear of the Tohu, he becomes motivated to productive living. His ability to sense destruction and inaction is what gives him the ability to get satisfaction out of building and creating. Someone who is aware of the world of Tohu - can not live in it.