The universe appears as the waking or the dream (duality) and disappears as the invisible Soul in deep sleep (nonduality).+

The Soul is the Self. The Soul is present in the form of consciousness. Consciousness is the substance and the witness of the dualistic illusion. 

The dualistic illusion is present in the form of the mind. The mind is present in the form of the universe. \

The universe appears as the waking or the dream (duality) and disappears as the invisible  Soul in deep sleep (nonduality).

The one which is aware of the coming and going, of the three states is neither the waking entity nor the dream entity, but the formless, timeless, and spaceless Soul, which is present in the form of consciousness.

When the Soul wakes up from the sleep of ignorance and the midst of dualistic illusion and remains in its own awareness then it is called the Atmic–awareness.

It is foolish to limit the consciousness only to the physical body because the consciousness pervades everything and everywhere in all three states. 

Thus, the Soul, the  ‘Self’ has nothing to do with the three states because the three states are an illusion created out of the consciousness.

If the three states are an illusion created out of the consciousness, then the experience of birth, life, death, and world which is experienced as a reality within the waking experience is an illusion created out of the consciousness. 

Without the illusion, only the fullness of the consciousness prevails as the ultimate reality.

From the standpoint of the  unborn  Soul, the ‘Self’:-

There is nothing to accept,

Nothing to reject,

Nothing to hold on to,

Nothing to let go of,

Nothing to grasp,

Nothing to spurn,

Nothing to embrace

, 

Nothing to relinquish,

Nothing to dissolve

The world in which we exist is a dualistic illusion. The dualistic illusion is created out of a single stuff. That single stuff is the Soul, which is present in the form of consciousness. Thus, consciousness alone is real because there is no second thing that exists other than consciousness. This is the truth. :~Santthosh Kumaar