The cause and origin of the three states is formless soul, the innermost self. The soul, the innermost self is present in the form of consciousness. Consciousness appears as waking or dream(duality) and disappears as deep sleep (non-duality). Thus it is for the seeker to know what appears as duality (waking or dream)and what disappears as non duality (deep sleep).
The body and the world exist only in duality (waking or dream). They are non-existent in non duality (deep sleep). To unfold this mystery, one has to know 'what is the mind?' and 'what is the substance of the mind?' and 'what is the source of the mind?'
Only in duality (waking) one knows that he exists, in deep sleep the objective existence is absent.
One is aware of his body and sees his body moving and thinking. But he is unaware of the fact that he and his experience of the world are within the experience of duality (waking).
One has to realize the fact that the body also moving and thinking and being in all sorts of places in the dream while it is actually lying fast asleep. The dream is reality until waking takes place. The waking also is reality until the wisdom dawns.
Existence cannot be a cause and effect at the same time, from the point of view of the dualists, but deeper self-search shows the Existent is no-two and causality can’t rise at all. Dualistic theory says that whatever was in the cause was also in the effect. They say that the gold brick, the gold medal, the gold ornaments --are in the seed--the gold. Deeper self-search reveals the fact that, if cause and effect are one what is the difference between the two?
So long as one is in the realm of duality, one has to explain how or why one thing came from another; and contradictory views are expressed. But when a Gnani show- there is no second, there is no production, and the contradictions do not arise at all, when the ultimate thing is consciousness alone. Thus consciousness is ultimate truth or Brahman.
The dualists’ arguments are based on false self (ego or waking entity) and false experience (waking or dream or universe) to show the weakness of the position of dualistic view point. They at their wits end to explain.