Only through deeper analysis the three states, one becomes aware of the existence of the formless witness.

Those that want to prove existence of formless witness; it is only in its presence, for it is awareness, that proof can be given. It is a pre-condition without which one cannot talk of proof.  The formless witness is the substance and witness of the waking experience, which contains man, and his experience of the world.  Without the waking experience man and his experience are absent. The three states are transient in nature.  Thus there must be a knower of the three states which appear and disappear in succession.

Only through deeper analysis the three states, one becomes aware of the existence of  the  formless witness. 

v  How does one see the dream?

 The dream is witnessed without the physical eyes.  So it was not the waking entity, which witnessed the dream. The waking entity and the waking world was absent in the dream. If the dream world were without the witness, it is impossible to witness the dream. Therefore there must be a witness of the dream. This same witness is witnesses the waking experience as a whole. And also the deep sleep.  Thus the formless witness has to be mentally grasped by constant reflecting on the subject.

The gross waking experience is merged into the mental experience in the sense that when it is analysed, it is found to exist inseparably in and as the mind alone.  All "spiritual" planes are really mental.

The existence of the three states is the proof of the Formless witness. The moment one becomes aware of the witness of the dream is not the waking entity, then he becomes aware of the existence of the formless witness of the three states, which is apart from the three states.

 All the three states are produced by ignorance, and dissolves in the wake of non-dual wisdom. The material /cause of this the duality is the One without a second, subtle and unchanging Existence, just as the water is the material /cause of the cloud and the like.

The soul is the innermost self. The soul is in the form of consciousness. As soul or consciousness, the innermost self is also the One, the Subtle, the Knower, the Witness, the Ever-Existent, and the Unchanging, so there is no doubt that it is the consciousness.

Consciousness the true self is verily one and without parts, whereas the body consists of many parts; and yet everyone confounds these two as one due to ignorance.

Consciousness is the ruler of the three states and is internal; the three states are the ruled and are external.

Consciousness is permanent.  All the three states are an illusion created out of consciousness. Consciousness is the Illuminator and purity itself; the three states are said to be of the nature of darkness.

Consciousness is eternal, since it is Existence itself; the three states are transient, as they are non-existence in essence.

It is very strange that a person ignorantly rests contented with the idea that the self is the body and world as reality, while he knows that the body and the universe exist because of the consciousness.

True Self verily consciousness, being equanimous, quiescent, and by nature absolute Existence, Knowledge. The true Self is neither the body nor the mind which is non-existence in their essence. This is called true Knowledge by the Gnani.

Consciousness is without any change, without any form, free from all blemish and decay. Consciousness not subjected to any disease, and it is beyond all comprehension, free from all alternatives and all-pervading.

Consciousness is without any attribute or activity, true self is eternal, ever free, and imperishable.

Consciousness is free from all diversity; true self is immovable, unlimited, undecaying, and immortal.