1 - Namarupa Pariccheda Gnāna
If we are to take “nama-rupa-pariccheda-ñana” to mean, “rupa” are according “nama” - one’s body is according to one’s thinking, then it means that our habits help form the kind of existence in life. An adulterer’s acts can be equal to that of animals. Such activities would generate kamma beeja in the animal bhava in the next life.
Nama-rupa paricheda-nana can be also taken as one being able to see oneself as five grasping groups (Pancaupadanakkhandha). Those five are namely:
Rupupadanakkhandha - Grasping group of corporeality
Vedanupadanakkhandha -Grasping group of feeling
Sannupadanakkhandha - Grasping group of perception
Sankharupadanakkhandha -Grasping group of mental formation
Vinnanupadanakkhanda-Grasping group of consciousness
These are the five aspects through which the Buddha has summed up all the physical and mental phenomena of existence, and which appears to the ignorant man as his Ego or personality. It is also called Ditthi-Visuddhi.
2 - Paccaya Pariggaha Gnāna
The cause of all the physical and mental phenomena of existence (Nama-rupa) is no other than Avidya (non-awareness of truth), Thrusna (desire or craving born of false views and attachment), Kamma, and Ahara (nutriments). It was true in the past, it is true in the present and it will be true in the future. Nana or insight which realizes this fact is called Paccaya-pariggaha-nana. It is also called the purification by overcoming doubt kankhāvitarana-visuddhi.
By purification by overcoming doubt (kankhā-vitarana-visuddhi) is meant the understanding which, by grasping the conditions of this mind and corporeality, has escaped from all doubt with regard to the 3 times (past, present, future). Ahara (nutriments) are of four types: The foods for the physical body are called kabalinka ahara. Sense impression (phassa ahara) is Contact, Volitional thought (Cetana) is Intellectual Intention, nutriment of Consciousness, and
3 - Sammasana Gnāna
This is Knowledge by Comprehension. Here the knowledge that one gained in the above two Namarupa Pariccheda Gnāna & Paccaya Pariggaha Gnāna are seen in relation to Anicca, Dukkha and Anatta nature.This Nana or insight is called Sammasananana.
On proceeding with the contemplation, oneobserves that all rupa cannot be kept to one’s satisfaction. This is "Anicca-sammasana-nana" (Insight that nothing can be kept to one’s satisfaction, that leads to suffering, and is a viparinama dhamma).
Thus one understands that no “rupa” can be kept to our satisfaction, therefore that (i.e., forming attachment to such rupa) will lead to suffering, and therefore there is no reason to consider of them having any substance. Anicca leads to dukkha and to anatta, because we have nicca sanna about such (anicca) rupa.
4 - Udayabbaya Gnāna
This is Knowledge of Contemplation of Arising and passing Away. “Udayabbaya gnana” when one develops, one can see the causes that need to be eliminated to overcome otherwise inevitable future suffering. One then learns of the factors relating to all knowledge about the arising and destruction of anything in this world. It is also called Maggamagga-nana-dassana-visuddhi.
By purification by knowledge and vision of what is path and not-path (maggāmagga-ñānadassana-visuddhi) is meant that understanding which knows the right path from the wrong path: 'This is the right path, that the wrong path.' This knowledge is the mature form of Udayabbhayanana", flawlessly free from 'Upakkilesa' (impurities).
One practising Vipassana meditation, at this stage, generally beholds a supernormal light (obhasa), feels a thrill of zest (piti), calmness (passaddhi), determination (adhimokkha), great energy (paggaha), happiness (sukha), deep insight (nana), intensity of mindfulness (upatthana), equanimity (upekkha), and a mild desire for this state (nikanti).
These states arising in one at the stage of Udayabbaya Nana in ten phases are termed 'Vipassanupakkilesa’, defilements of kilesa. These are imperfections of Insight and are ten in number, as follows: (1) Illumination, (2) knowledge, (3) rapturous happiness, (4) tranquility, (5) bliss (pleasure), (6) resolution, (7) exertion, (8) assurance, (9) equanimity and (10) attachment.
One, arriving at this stage, is liable to these defilements and his mind may be seized by 'spiritual excitement' or 'agitation about higher states' (dhamma-uddhacca). 'For example, he may, on having an illumination, feel that this constitutes Path-experience and so inhibits his further progress through deceiving himself.
5 - Bhanga Gnāna
This is Knowledge of Contemplation of Dissolution. This is the first of a series of nanas known as the dukkha-nanas. At this stage one has already attained the purification of overcoming doubt and the purification of knowing and seeing what is and what is not the path. The essentials of the practice have already been revealed, and in the process the one has experienced confidence, rapture and bliss, and had seen the arising and passing away of experience.
As the awareness and concentration continues to develop one now sees only the passing away of phenomena. It is as if one’s awareness is faster than the experiences he is examining, As soon as he places his attention on some aspect of his experience, it disappears. This is the knowledge of dissolution (bhanga-nana). This can take the form of one apparently losing one’s concentration, like one can no longer focus on anything; one’s attention keeps sliding off whatever one tries to look at.
This can be a shocking experience, because one is used to be able to focus on anything. Now, it seems, one can focus on nothing at all. One can even experience the disappearance of the form of the body. The sense of the body disappears; all that is left is a series of apparently disconnected individual sensations. There is no "body" as such.
6 - Bhaya Gnāna
Bhanga-nana gives way to the knowledge of fear, (bhaya-nana). In the disappearance of everything examined, the mind at some level begins to realise: there is nothing beneath. There is no foundation.There is nothing at all. This can manifest as panic. The realisation that "I am not in control of ‘my’ life".
7 - Ädeenava Gnāna
Contemplation of Ädeenava as bad consequences is another aspect of the awareness of a sense of fear: Temporary enjoyment (asvada) is bound to bring about bad consequences (adeenava). There arises the realization of the fact that these psycho-physical phenomena so rapidly dissolving are undesirable, faulty and defective in nature. This is "Adinava-nana" (Insight into unsatisfactory condition)’.
One realises there is no rest, no security, in anything. The power of this insight-knowledge is such that one knows there is no escape. One knows that this danger, this disadvantage, remains because one knows this is the nature of experience as such.
8 - Nibbida Gnāna
This is Knowledge of Contemplation of disenchantment. If we could stay away from valuing sense pleasures and live accordingly, then we could arrive at this gnana. Thus, one would contemplate on the endeavor to break all bonds to this world, and stop making new bhava. It is a conviction that it is unfruitful to stay in this world as there is nothing in this world that worth craving for (upadana).
9 - Muncitukamayata Gnāna
This is Knowledge of Desire for Deliverance. Knowledge consisting in the desire for deliverance means: the desire for freedom and escape from all mental formations of existence. For feeling aversion for all mental formations, becoming weary of them, finding no more delight in them, the mind does not cling to a single one of all these mental formations.
Simply put this is the "get-me-outa-here-nana". And of course, this knowledge includes the understanding that, whatever situation one could escape to, that too will be unsatisfactory, and the urge to escape will still be there in that new situation.
10 - Patisankha Gnāna
This is Knowledge of Contemplation of Reflection. In reflecting, one instills a decision to practice further. At this stage as contemplation is carried on with reflection, carefully, with proper care or intention, a clear perception of 'anicca', 'dukkha' and 'anatta' would arise. In particular, the nature of dukkha, sufferings, may be perceived very convincingly.
This is 'Patisankha nana" (Insight arising out of further contemplation; Nana or insight that regains the awareness of Anicca or Dukkha or Anatta nature of all things. That none of those can be maintained to our satisfaction, i.e., they all are anicca. Thus we eventually suffer, and thus all struggles to keep them to our satisfaction are in vain and therefore, we are helpless in this rebirth process.
11 - Sankharupekha Gnāna
This is recollection once more of the afore knowledge, in fully comprehending that nothing can be maintained to our satisfaction, i.e., they all are anicca, thus we eventually suffer, and thus all struggles to keep them to our satisfaction are in vain and therefore, we are helpless in this rebirth process. The realization of the true nature of the objects of contemplation without exertion and without pursuing good or bad sensations in the course of the contemplation which lasts for a long time is "Sankha-rupekkha-nana" (Knowledge or insight arising from viewing things with equanimity; Nana or insight, that is indifferent to Arammana [thought objects]).
12 - Anuloma Gnāna
This is Knowledge in Conformity with Truth-conformity knowledge. When one comprehends anicca, dukkha, anatta to the extent that one gets to ‘see’ this Tilakkhana, one is said to have the “anulöma nana”.
That special knowledge appears with the realization that physical and mental phenomena which occur at the six sense-doors momentarily cannot be maintained to one’s satisfaction, will eventually lead to suffering, and everything in this world is without substance (anatta).
The knowledge that arises at the last moment is "Anuloma-nana" (Knowledge of adaptation) which consists of three 'javanas', impulse moments, called 'Parikamma' (preparation), 'Upacara' (approach) and 'Anuloma' (adaptation). Anulomanana transforms mind to become qualified to enter the threshold of Nibbana.
13 - Gotrabhu Gnāna
After 'Anulomanana' there arises "Gotrabhu-nana" (Knowledge of Change-of -lineage ("götra") when getting close to a jhana) which grasps the sensation towards Nibbana where the miseries and sufferings connected with rupa and nama entirely cease.
Gotrobhunana pushes mind across the threshold. As soon as mind crosses the threshold, it becomes aware of Nibbana. This is the knowledge which severs the lineage of 'Putthujjanas' (worldlings) and enters the lineage of the 'Ariyas' (Noble Ones)
14 - Magga Gnāna
This is Knowledge of Path. Knowledge and vision of what is path and not-path means that understanding which knows the right path from the wrong path: 'This is the right path, that the wrong path.' In order to attain this gnana, one at first should develop methodical insight.
15 - Phala Gnāna
This is Knowledge of fruit. No sooner the "sotapatti Magga Nana” arises one comes to Phala Nana" (Insight wisdom arising from the Noble Path of Stream-winning and its Fruition) which realises Nibbana. The 'Magganana' is called "Nana-dassana-visuddhi" (Purity of insight)
16 - Paccavekkhana Gnāna
Once the 'magga and Phala Nana' arises, then retrospective reflection of the peculiar experiences of the "Magga, Phala and Nibbana" takes place. This is 'Paccavakkhana-nana" (Insight of retrospection). This is Knowledge of Reviewing. 'retrospective knowledge', refers to the recollected mental image obtained in concentration, or to any inner experience just passed,
Knowledge which reviews the defilements still remaining.