I am listening to Adyashanti’s True Meditation and Spontaneous Awakening, and find a deep appreciation for the wonderful simplicity, freshness and clarity of his teachings. I also see how the practices he talks about come from a Buddhist tradition, which is not surprising since he studied with a student of Maezumi Roshi, as I did/do as well (in my case, Genpo Roshi).
What Adyashanti describes as true meditation, just allowing anything arising to be as it is, is a description of shikantaza, or what is sometimes called just sitting. And the practice of meditative self-inquiry is similar to koan studies, and even more similar to the Big Mind process developed by Genpo Roshi.
The meditation allows awareness to notice itself as aware of content, and also as no different from its content. Said another way, it shifts the center of gravity from the content to the seeing of the content, allowing the content to live its own life.
The inquiry allows for a clearer seeing of this process, and also for a clearer seeing of what we really are. Am I the changing content? Am I that which does not change? Am I the seen? Am I the seeing? Is there a separation between the changing content and that which does not change? Am I the seeing and the seen?