Ajahn Chah would explain that the mind’s nature is still, yet it’s flowing. It’s flowing, yet it is still. He would use the word “citta” for the knowing mind, the mind of awareness. The citta itself is totally still. It has no movement; it is not related to all that arises and ceases. It is silent and spacious. Mind objects — sights, sounds, smell, taste, touch, thoughts, and emotions — flow through it. Problems arise because the clarity of the mind gets entangled with sense impressions. By contemplating our own experience, we can make a clear distinction between the mind that knows (citta) and the sense impressions that flow through it. By refusing to get entangled with any sense impressions, we find refuge in that quality of stillness, silence, and spaciousness, which is the mind’s own nature. This policy of non-interference allows everything and is disturbed by nothing.
Ajahn Amaro, Small Boat