Updated: Feb 18, 2020
How about, what is not in your mind? Or is what you see, hear, smell, touch, and taste not it at all?
Neurology and Zen have had many dance partners The Dalai Lama's work at the Emory School of Medicine or the work of Dr. James H. Austin, a retired academic neurologist, and longtime Zen practitioner.
Austin writes of egocentric and allocentric awareness the former establishes reality in relationship to "me," while allocentric is not ego-relational, but just a form. https://tricycle.org/magazine/your-brain-zen/
The object used most often in the history of Zen to address this quandary is a mirror. Hence the back and forth of Shenxiu and Huineng. This is a story about ME versus IT. Shenxiu's tree, mirror dust, and cleaning verses Huineng's no tree, mirror, or place for dust to light. Perspective holds for discussion. Points of view and angles of awareness are philosophical, not Zen.
Matsuoka-Roshi in Kyosaku page 16 offers:
"Objects are not distinguished between in their reality...when one's mind becomes empty everything is oneness and no longer thoughts of self." To which I would add nor other discriminations.
Taiun-Roshi, my teacher and lineage heir of Matsuoka-Roshi pointed me to this insight regarding a Dharma Note in which I wrote about "Freedom of Religion." whereby he asked why not "Freedom from Religion?"
Huineng responding to Shenxiu...