"The phases are the expression of reflections. It is not enough to understand how a mirror or a pool of water works. When the glass is still, a reflection manifests itself. To see ourselves is but to give grace to the Divine for the mystery of our eyes. All men, as soon as they can comprehend themselves, understand that the person in the mirror is but a visual ghost of their shape. They do not think it real. They do not it will steal into their bedchambers. They know that, when they are gone, so too is the image. It exists only as long as they are present to observe it. In that sense, it is eternally bound to the object which it reflects.
"The dreamer must apprehend the third phase: that reflection of a reflection. Between the dreamer and his image is an area of discord. This shadow, this inference of what is not object and image but part of their reflection, is the simplest manifestation of the dream.
"In the same way that the dreamer uses his eyes to observe his image, he must not use his eyes to "see" his shadow. The worlds—observable, spiritual, and ephemeral—revolve upon a simple axis of what is and what is not. All is defined—reduced to its simplest construction—by dualities. The secret to moving between the worlds, to moving the mind past any definition is to comprehend the third reflection of any duality. What is, what is not, and what lies in the chaos between them.
"The dreamer is in the first phase as he prepares for sleep. As he falls under the influence of the moon, he enters the second phase. Most men think they are free in this phase. They think they are masters of this imaginary domain of shadow and darkness, but they are still bound by the inversion of their own identities. The dreamer—the initiate who wishes to comprehend the fullness of existence—must pass into the third phase: the realm beyond waking and identity, beyond memory and desire."
(from Safiq Al-Kahir's Book of Dreams)