What is anuloma-nana and how does this adaptation-knowledge makes the switch from the mundane to the supramundane world?
Ñānadassana-visuddhi - 'purification of knowledge and vision', is the last of the 7 purifications and a name for path-knowledge, maggañāna i.e. the penetrating realization of the path of Stream-winning, Once-returning, Non-returning or Arahatship. The Knowledge of Adaptation (anuloma-ñana) comes under this seventh purification.
The only sutta that fully explains the seven purifications is Rathavinita Sutta. It explains in full the seven purifications (SAPTHA VISUDDHI) taught by the Buddha. The Ratha-vinita Sutta: Relay Chariots (MN 24; M.I,145).
The only place in the Canon where these 7 kinds of purification are mentioned is M. 24,, The Simile of the Stage-coach; There it is said that the real and ultimate goal does not consist in purification of morality, or of mind, or of view, etc., but in total deliverance and ceasing. Now, just as one mounts the first coach and travels to the second coach, then mounts the second coach and travels with it to the third coach, etc.,
in exactly the same way the goal of (I) the purification of morality (sila-visuddhi) is (II) the purification of mind (citta-visuddhi)
its goal: (III) the purification of view (ditthi-visuddhi)
its goal: (IV) the purification by overcoming doubt kankhāvitarana-visuddhi
its goal: (V) the purification by knowledge and vision of what is path and not-path (maggāmagga-ñānadassana-visuddhi)
its goal: (VI) the purification by knowledge and vision of the path-progress (patipadā-ñānadassana-visuddhi);
its goal: (VII) the purification of knowledge and vision (ñānadassana-visuddhi)
but the goal of this purification is deliverance freed from all clinging.
By the purification of knowledge are here meant the following, which are freed from defilements, follow the right process, and are considered as insight, namely:
- knowledge consisting in contemplation of rise and fall (udayabbayānupassanā-ñāna),
- in contemplation of dissolution (bhangānupassanā-ñāna),
- in awareness of terror (or the fearful) (bhayatūpatthānā-ñāna),
- in contemplation of misery (ādīnavānupassanā-ñāna),
- in contemplation of aversion (nibbidānupassanā-ñāna),
- in the desire for deliverance (muccitu-kamyatā-ñāna),
- in reflecting contemplation (patisankhānupassanā-ñāna),
- in equanimity regarding all formations of existence (sankhārupekkhā-ñāna) - which is followed by
- in adaptation to truth (saccānulomika-ñāna) ie. anuloma-nana.
So there is a very long way for you and I to go in this Path before coming to this anuloma-nana. Wisdom derived from the preliminary nanas, the ones before it. This Anuloma nana has the characteristics of anicca, dukkha and anatta. In the anuloma nana, the Four Noble Truths appear clearly and distinctly.
Yogi with dedication work hard in meditation achieving lower nana stages step by step , will attain the knowledge of equanimity regarding the formation where all notice on phenomena is so clear cut that each and every detail can be noted without much effort and to the exact timing. With more effort and further concentration, noting on these phenomena become faster and faster , more and more subtle with great moment until all of a sudden, all these cease to be, reaching gotrabhu.