Psychology is based on the body as self. They believe the mind is limited to the individual. Psychologists commit the error of defining consciousness as a duality of Mind plus the object! Unless both are together there is no awareness of experience. They deny that consciousness can exist apart from objects. But without the consciousness one will not be aware of the deep sleep. The consciousness can prevail with or without the waking or dream experiences, as in deep sleep. Thus, deep sleep is given as a valuable warning against such an erroneous position.
Many do not go into the question what is mind? What is substance of the mind? “What is meant by mental?" or what is beyond mind? That is, because they are is ignorant of the formless witness.
Psychology has nothing to do with the formless witness, because they consider the physical eyes [body] to be the witness. The psychology discusses that which is aware of all these things and ideas and processes and reactions. But the truth is beyond psychology, because psychology is limited to the three states. The beyond [consciousness] is aware of the three states, which comes and goes. When the consciousness becomes aware of its true nature, the three states are mere mirage created out consciousness. Thus in the realm of the formless non-dual true nature of consciousness there is no scope for duality, because there is only non-dual reality.
The only certain thing about the body is that it is forever changing; the greatest change of all being death which no one can prevent. In contrast to the body the consciousness is the only thing of whose unchanging character one can be certain. For the consciousness tells one about all the bodily changes, remaining itself relatively constant, as a standard of reference for them.
One can never know what the mind really is without deeper inquiry, analysis and reasoning. One has to study deep enough by analyzing the three states. Most people are unaware of it because they stick to the idea mind is within the body and every individual has his own mind. But if one wants to study formless witness , he must make the three states as an object ; and if it becomes an object , it is no longer the witness , no longer the mind; if he wants the formless witness as it really is, then it is absolutely impossible to study it. Only Mentally one can grasp it.
The three states can all be summed up in one word – Mind. Mind is seen/object never the witness. The term Witness, Seer, is used in a non-dual sense, without reference to objects witnessed, absolute awareness, not relative.
Thinker and Thought are present in waking or dream. The thoughts cannot rise without the form. Thus the thinker has to be the form. Thus the thought comes to the form. Without the form the thoughts ceases to rise. The form rises only in waking or dream. Without the waking or dream the form ceases to exist. The waking or dream exists only when the mind is present. The waking or dream ceases when the mind ceases. Your mind produced the thought. Thoughts, feelings, rises along with the mind subside along with the mind. Even if it is of God, it is still within the mind. Thus mind rises as waking or dream [duality] and subsides as deep sleep [non-duality]. Thus consciously becoming aware of the non-duality in the midst of duality is wisdom.
Once one really understands that all three states are objects to the subject, you may hope to understand non-duality but without it he never will.
Birth, life death and universe are experiences within the waking or dream, which are object to the subject. Therefore, birthlessness is the characteristic of non-object, i.e. the true self, which is consciousness.
It is erroneous to recognize the mind, which is in the form of the universe as different from consciousness, which is the true self.
Except self-illuminating consciousness, the universe or mind, which is mirage gets reflected by that supreme light. The universe originates from consciousness, sustained by consciousness and dissolves unto consciousness.