The two kings of Jnana-type meditation are the "Who Am I?" meditation, and, simply abiding in the self.
Both meditations are amply covered in Robert's book, Silence of the Heart (the pre-2010 versions of the book is best), and Ramana Maharshi’s early books.
Collectively these practices could be (mistakenly) called going within oneself, or going deep within oneself.
However, it is not simply a matter of looking within and pushing the envelope of the ever expanding clear light void which contains all phenomena, both inner and outer, because there is still the presumption that the Void exists and there is a perceiver thereof. That is, there is still the presumption of an inner and outer, of subject versus object, in this case, the object being the void.
The best way to conceptualize going within is that we are looking for the ultimate subject; we are trying to objectify the subject, rather than objectify the void. Of course we will find that the subject cannot be objectified. But abiding in subjectivity leads to becoming the subject.
Most of us assume that there is a witness and a world witnessed. We take that witness to be the equipment we associate with the body: vision, taste, sound, etc., as well as thoughts, emotions, attachments, the sense of belonging, ownership, as well as daydreams, memories and fantasy. Versus this, is the entirety of the external world, or not-me.
By this time we should have realized the so-called subjective phenomena are exactly the same sort of reality or level of existence as our percepts of the apparently external world. They are of exactly the same stripe. They are all objects including the inquiring mind.
Merely probing the inner space, in a sense, only exaggerates and objectifies the split between subject and object.
This is a mistake I made for many years, an endless exploration of the void with an awareness of a subjectivity exploring the void, with the ultimate realization that this process will reveal nothing except more Void.
One step further must be taken, which is to attempt to grasp that which is aware of a subjectivity exploring the Void. That is, we try to objectify the ultimate subjectivity, and the failure of which, results in discovering how to abide in the self through failure of the quest for self.
This makes the practice of Who Am I, or abiding in the self, far, far different from the way the process is described in books even by Robert, because Robert is speaking to a meditator who has the mistaken perspective of the self as a variety of phenomenon. Robert is trying to get the person into a calm introversion which allows the solidity of phenomena to open to an extent such that the subject, I Am, can differentiate and begin to contemplate itself.
Instead of just going within and probing the inner darkness or illumined space, we try instead to either look into our sense of existence, or into the subjectivity of that who is perceiving. We no longer just look within but we look for the witness. By the witness, I mean the felt-sense that I am the perceiver of the world. Yet, this seeker of the Witness is still phenomena, thought, concept, or what everyone calls the ego. “Ego” is just a word. We think we understand the whole process once we hear that word as there is an enormous amount of purported “knowledge” associated with that term, therefore, I avoid it.
Truly we are looking for the ultimate subject, the absolute subject, he that perceives the body as just another object, yet itself is not in object, nor can it become an object. This is a paradox. We look for that which is not perceivable.
Another similar practice is to become aware by inquiry that we exist; that is, be aware that I Am.
I might say I had a difficulty with his practice for a long period of time because I was never sure that I existed. I appeared to exist, but I did not have the sense that I existed. The sense of existence, or of I am, is only to be found by being aware of the feeling-source of all that is, as if we could split between the world and I. We look for the I as the felt-sense of existence. Again, we are looking for the subject, but this time through the medium of having a felt-sense of something or someone who exists. That is, we are looking into "I Am." This can be an elusive target for long period of time.
The apparently separate body-mind has no existence at all, therefore looking for I Am within that complex is fruitless. The sense of I Am is separate from the sense I am a body.
Personally, I favor the searching for the ultimate subject technique as it was easier for me. Some might say they are the same and in the largest sense they are; however, from a practitioner’s viewpoint, they can be very different.
It took me a long time to realize that going within, for me, meant space/void/mind exploration, while what I really needed to do was to flee into subjectivity away from objects as opposed to fleeing into the Void to escape objects. Until you have done this practice for time, it is hard to notice the difference. Going within is not a spatial thing, but a heading towards the sense of the source of sentience. The void is not subjectivity, it is still an object.
For the longest time, when I went within, there was a feeling of "solidity" within the void that was centered in my heart area. That is, I felt my essence, so to speak, was involved with the heart center and that it was my job to penetrate and clarify that area. Strangely, this was Ramana's instruction, to look within the heart area. But this is a mistake. There is still a looker who is objectifying the heart area phenomenon which was within space and time; yet, who is the looker? Seeking within the heart area makes it important and more real, just like concentrating on the body make sit more real. In one mind, inward and outward disappear.
Robert describes the "Who am I?" Meditation as not following the I inward, but asking the question and gently probing within for He who asked the question, and in that space, to abide in silence—that is, without seeking. I do not like this meditation, as I practice it for a long period of time, and because of my misconception of the question as a device to seek an ever retreating subject, I got lost in the Void. “Who am I?” has altogether too much mentation.
Therefore, search within for that which is the perceiver and attempt to abide there. The attempt itself will be a failure, but persistence will allow one to abide in silence, as the dichotomy disappears, and the ultimate subjectivity will reveal its mysteries just in this calm abidance.