When it comes to the spiritual practice of Self Inquiry, it is actually very simple. However, because it is approached improperly, it seems complicated or even impossible. Let us look at this issue in some detail.
When a seeker first comes to the topic of Non-duality or Advaita, he or she (going forwards for sake of ease of writing, only the pronoun "he" shall be used although it encompasses all) approaches it like any other objective knowledge. He takes for granted that he is an entity - the idea that "I am a body made up of flesh and bones" - who is going to study and attain knowledge about the non-dual Reality just like he would any other objective knowledge. While initially this approach is perfectly alright, eventually difficulty will be encountered. By this approach, only an inferential knowledge can be gained. Meaning thereby, one can understand some of the basic principles about the Unreal and the Real. However, Knowledge about the Ultimate Reality will not be obtained by this method.
As long as one does inquiry of the Self maintaining a separate and independent idea or conviction of being a body-mind entity, there is no hope of realizing the Self. The Self is not some thing that is to be attained. Such an approach will only lead one down a rabbit hole of innumerable concepts about the nature of the Self, all of which would be false since they are just concepts. The non-conceptual Self cannot be known in the form of concepts!
In Self Inquiry, the most important investigation is actually to find out if and where the "I" exists. Yes, this "I' is the same "I am the body with a mind" entity we are talking about - i.e. you, the reader. Let us see, right here and now, if there is actually an entity that is reading this passage. In this case, the passage is the object of the vision and there is apparently an entity calling himself the "reader' of this passage (the subject). To keep things simple, the passage appears as an image on the retina of the eye thereby triggering electrical impulses. The electrical impulses travel via the Optic Nerve and reach the portion of the brain called the Visual Cortex. So far, so good. But, is there really some entity or someone who is analyzing the electrical information? Look carefully to see if there is really an entity, an occupant in the solid mass of tissue called the brain, who is looking out through the windows called the eyes and then declaring " I am seeing". Or, as is obvious on careful analysis, what is obviously a mass of water and other elements (constituting the brain) is incapable of actually "seeing" or even "analyzing" the information received at the visual cortex. So, who is this "I" that is apparently reading or analyzing the information and where is the location for this "I"? The same investigation can be done for other actions or sensations that are perceived by the body. Further, the same investigation can be done asking - who is the "feeler" or the "thinker"?
So, it becomes clear from the inquiry, that there is a mysterious entity called "I"- an owner occupant- that takes ownership of the body and all its actions and also ownership of the thoughts and feelings. One must investigate, who exactly is this "I" who has appeared in the waking and the dream states to take ownership of the body and mind? However, this "I", along with the world of objects seems to somehow disappear or subside in deep dreamless sleep. Yet, when one wakes up from sleep, one usually has memory of having slept as is obvious, when upon waking, one states - " I slept happily". It is obvious that there is some other non-entity that is aware of the three states of wakefulness, dream and deep sleep and yet is unaffected by all these states. That which is beyond these three states is referred to as the "Turiya" (literally meaning the fourth). However, it is not a state since the other three states appear in it. To avoid going down the rabbit hole, let us get back to you - the "I" - the doer, the reader, the thinker, the feeler, the perceiver, the sufferer, the enjoyer etc.
There are many other investigative methods mentioned in the Advaitic literature and shastras. Regardless of which method you use, the focus of attention should always be on this " I am the body" idea. Where did the idea or thought "I am the body" arise from? What is the source? Is the "I" an entity or is it just a thought? What are thoughts? Is there any such thing called the "mind"? Or is the mind just thoughts and nothing else? Hang on to the "I -thought" once you have established that it is just a thought. Is it not true that all other thoughts are anchored to this "I- thought"? Can other thoughts exist in the absence of the "I-thought"? Do you exist in the absence of thoughts?
Knowing the Self is being the Self. When the idea of individuality disappears, the Self which is always self shining and always here and now becomes self evident. No one has to go searching for the Sun using a lamp! Eventually, you will realize that the entire exercise of self inquiry is being played out in the mind, which in itself has no existence apart from the Self. It is ONLY when the mind finally becomes STILL, that the Pure Awareness shines through. The way to stillness is to inquire who is this "I" and the "I" disappears like a ghost or phantom - as it no longer has any object or form to hold on to. Stillness is beingness.
