A great deal of our lives are spent walking in the light of the dayworld, where we identify with the Ego. The Ego is necessary to our survival in waking life. We function in the world of space and time via the Ego. It is three-dimensional, Apollonian, and Herculean. It is our waking Ego. This self, however, has a very special companion. The waking-Ego is shadowed by our dream-Ego, the person we identify with in our dreams. The dream-Ego is a shadow-Ego, or so we say. Is there any reason, short of our dayworld bias, that causes us to think of our waking-Ego as a more genuine self, and the shadow-Ego as the lesser, more inferior self? Is this dayworld merely the shadow of the underworld and our waking-Ego the shadow of our underworld-Ego? In my opinion, these two modes of presence, dayworld and underworld, shadow each other perfectly. Because we are so thoroughly identified with our dayworld-Ego, we critically need to become more familiar with our underworld-Ego by journeying down into Hades, boarding Charon's ferry, and making our way across the Styx, past Cerberus, and into the realm of the Dead.
"Entering the underworld" refers to a transition from the material to the psychical point of view (James Hillman, The Dream and the Underworld, p. 51).
Night, by Mikalojus Konstantinas Čiurlionis, Public Domain
The underworld is the realm of the Dead because Death is the ultimate unconsciousness. Those who die do not cease to be; we in the dayworld simply become unconscious of them. They will always exist. We may not be aware of them, but this doesn't preclude their existence. What is most crucial is that the underworld is the realm of Soul. The more we become familiar with it, the more Soul we accumulate. Soul and Death are intertwined like the serpents on the caduceus. Nightly, we travel downward, where we play out stories that are as old as the human species. Instead of trying to grab the shadowy figures we meet and drag them back up into the light of the dayworld (by trying to interpret our dreams so they make some kind of sense), it is in our best interest to remain there with them for a time and learn what they have to say. As we learn to recognize the archetypal motifs in our dreams, we come to know that life and death, dayworld and underworld, are two sides of the same coin. This is underworld epistemology.
The shadows of our dayworld Egos are very valuable. We tend to think of Hades in terms of a miserable Christian Hell, but it is not that at all. Hades is as much the god of wealth and plenty as he is the god of the realm of the dead. He is often depicted holding the cornucopia, or Horn of Plenty, symbolizing nourishment and abundance. This displays the value of shades in the underworld, the same shades we come in contact with every night. These figures are considered gods in many cultures. Our shadow-Egos are interpreted by these cultures as gods.
The dayworld Ego loves literalizations and ratiocinations; it loves to disparage imagination, intuition, and myth. The underworld-Ego thrives on metaphor, darkness, mystery, and perplexity. When you meet someone who tries to be totally logical and rational all the time, you can bet that person has not accumulated much Soul, if any.