In the case of jhana-condition, jhana-paccaya, the cetasikas which are jhana-factors are the conditioning dhammas which cause the citta and accompaying cetasikas, the conditioned dhammas, to fix themselves firmly on the object which is experienced. In the Visuddhimagga, in the section on the development of samatha, tranquil meditation (Ch 4), five jhana-factors are summed up, sobhana cetasikas which should be developed in order to reach jhana, absorption. These factors assist the citta to be absorbed in the meditation subject. When jhanacitta arises there are no longer sense impressions and there is temporary freedom from defilements. Jhanacitta is of a higher level of citta than kamavara citta, citta of the sense sphere. The word jhana has been explained as being derived from "jhayati", to contemplate, or to think closely of an object. Or else "jhayati" can mean to burn (Vis. IV, 119), since the jhana-factors which are developed burn the "hindrances" (akusala cetasikas) away.
The jhana-factors which are developed in samatha are sobhana cetasikas, they have to be developed together with panna which knows the way to develop calm, so that absorption can be attained. However, jhana-factors can also be taken in a wider sense, they can even be akusala. That is why the "Dhammasangani" mentions in the "Summary" jhana-factors arising not only with the maha-kusala cittas which are accompanied by panna, but also with those which are unaccompanied by panna, nana-vippayutta, as well as with each of the akusala cittas. Not only kusala citta but also akusala citta needs jhana-factors which assist the citta to be firmly fixed on an object. Even when someone performs evil deeds he needs jhana-factors which accompany the akusala citta, so that he is concentrated on the object of akusala; these jhana-factors condition the akusala citta by way of jhana-condition. We read in the "Patthana" (Faultless Triplet, VII, Investigation Chapter, §431) that akusala jhana-factors are related to their associated aggregates (the other namakkhandhas)  by jhana-condition. Without the assistance of the jhana-factors good or evil deeds cannot be performed.
When jhana is taken in its widest sense, the following cetasikas are jhana-factors:
- applied thinking (vitakka)
- sustained thinking (vicara)
- rapture or interest (piti)
- pleasant feeling (sukha)
- unpleasant feeling (domanassa)
- indifferent feeling (upekkha)
- concentration (samadhi)
Vitakka, applied thinking, "touches" the object which is experienced, it leads citta to the object (Vis. IV, 88). When vitakka is akusala it is wrong thinking. As to vicara, sustained thinking, this has the characteristic of "continued pressure" on the object, it keeps citta "anchored" on it (Vis. IV, 88). Vitakka and vicara accompany all cittas of the sense sphere, except the sense-cognitions (dvi-pancavinnanas, seeing, hearing, etc.) and they condition citta by way of jhana-condition, so that it is firmly fixed on the object it experiences. Piti, rapture, interest or enthusiasm, takes an interest in the object, it "refreshes" citta and cetasikas (Vis. IV, 94). In the case of cittas of the sense sphere, kamavacara cittas, it arises with all cittas which are accompanied by pleasant feeling. When it is akusala it accompanies lobha-mula-citta. As to sukha, in this context it is the same as somanassa, pleasant feeling. Domanassa, unpleasant feeling, can only accompany dosa-mula-citta, citta rooted in aversion, thus, it is a jhana-factor which is always akusala; it asists the akusala citta to be fixed on the object in an unwholesome way. Upekkha, indifferent feeling, can be kusala, akusala, or indeterminate (avyakata); when it is indeterminate it can be vipaka or kiriya. Samadhi, concentration, is the cetasika which is one-pointedness (ekaggata). It has the function of focussing on one object and it accompanies every citta; it can be kusala, akusala, vipaka or kiriya. It causes the citta to be concentrated on the object it experiences. Apart from domanassa which arises only with dosa-mula-citta, the other jhana-factors can arise with cittas which are kusala, akusala or indeterminate (avyakata). They each assist citta in their own way so that citta can be firmly fixed on an object. The jhana-factors condition the associated dhammas and the mind produced rupa by way of jhana-condition and also at the moment of rebirth they condition the associated dhammas and kamma produced rupa by way of jhana-condition (Patthana, Faultless Triplet, VII, Investigation Chapter, §431, VII a, b).
The subcommentary to the "Khandha-Vibhanga" (Book of Analysis I) explains the role of the jhana-factors in relation to mind produced rupa. This subcommentary calls the jhana-factors "strength-givers" (bala-dayaka), they are intensifying factors which assist the citta and accompanying cetasikas to be fixed on an object. The jhana-factors vitakka and vicara play a specific role when citta produces speech. Do we know whether there is kusala vitakka or akusala vitakka while speech sound is being produced? When our objective is not dana (generosity), sila (morality) or bhavana (mental development), we speak with akusala citta and this happens time and again. When citta produces a facial expression of gladness, or when we smile, the jhana-factor sukha plays its specific role, the jhana-factor piti (rapture) "refreshes" citta, in fact, all the accompanying jhana-factors condition citta, the associated cetasikas and the rupa produced by citta by way of jhana-condition. When someone commits an unwholesome deed, such as killing, nama and rupa which arise because of conditions perform their functions. The dosa-mula-citta is accompanied by vitakka which is in this case thought of violence, by vicara which is occupied with the object, by unpleasant feeling and by concentration which causes the citta to be firmly fixed on the object. The akusala citta and the accompanying cetasikas and also the mind-produced rupa are conditioned by akusala jhana-factors,"strength-givers" or intensifying factors, by way of jhana-condition. When we perform a generous deed, the kusala citta and accompanying cetasikas and also the mind produced rupa are conditioned by sobhana jhana-factors by way of jhana-condition. These dhammas are also conditioned by root-condition, by faculty-condition and by several other conditions. Thus, as we have seen, jhana-factors are not only operating while one cultivates jhana, they are conditions which function time and again in daily life, no matter whether we perform wholesome or unwholesome deeds.
The Visuddhimagga (Ch IV) mentions five of the seven jhana-factors, in that case sobhana cetasikas, which have to be developed in samatha with the purpose of attaining jhana. However, there must be panna which knows the characteristics of those particular jhana-factors and which knows the way to develop calm with a suitable meditation subject. One will not attain true calm merely by sitting and trying to concentrate on one object. There are forty meditation subjects of samatha and it depends on the individual which subject is suitable as a means to develop calm (Vis. Ch IV-Ch X). For the development of samatha it is essential that there is panna which knows exactly when there is akusala citta and when there is kusala citta with calm.
The sobhana jhana-factors have each their own function in inhibiting the hindrances so that calm can be developed. Vitakka, applied thinking, "touches" the meditation subject; it thinks of it in the right way. Vicara, sustained thinking, keeps the citta "anchored" on the meditation subject, reviewing it over and over again so that citta will remain fixed on the meditation subject. Vitakka inhibits the hindrances of sloth and torpor and vicara inhibits the hindrance of doubt. Piti, enthusiasm, takes an interest in the meditation subject so that one is not bored with it. It inhibits the hindrance which is ill will. Sukha which is developed in samatha is happy feeling concerning the meditation subject. It inhibits the hindrances which are restlessness and regret (uddhacca and kukkucca). Upekkha is not mentioned among the jhana-factors which should be developed in samatha for the attainment of jhana, but in the fifth stage of rupa-jhana there is upekkha instead of sukha. Samadhi, concentration, developed in samatha, is samma-samadhi, which is right concentration on the meditation subject. It inhibits the hindrance which is sensuous desire (kama-cchandha). As calm grows samadhi also develops. There is miccha-samadhi, wrong concentration, and samma-samadhi, right concentration. If there is no panna which knows precisely when there is kusala citta and when akusala citta, wrong concentration can be taken for right concentration. Someone may mistakenly believe that there is calm when he just sits and for example looks for a long time at a kasina (disk) which is among the meditation subjects of samatha. Instead of true calm which is wholesome there is clinging to quietness.
Not merely intellectual understanding of the jhana-factors is needed for the development of calm but there must also be right understanding which discerns precisely their different characteristics. When one underestimates the difficulty of the development of jhana there is bound to be wrong concentration. It is difficult to distinguish between different jhana-factors such as vitakka and vicara. While we are thinking, there are vitakka and vicara performing their functions, they arise together; but do we discern their different characteristics? Do we know the characteristic of piti, rapture, and can we distinguish it from sukha, pleasant feeling? When we find out for ourselves how difficult it is to distinguish between these jhana-factors, we will understand that a high degree of panna is needed for the development of the jhana-factors.
When someone has attained the first stage of rupa-jhana the rupavacara kusala citta is accompanied by all five jhana-factors and these condition that citta by way of jhana-condition. After having emerged from jhana one has to review the jhana-factors with mindfulness and right understanding (Vis. IV, 138). Also in samatha mindfulness and right understanding are needed but the aim is not, as is the case in vipassana, to see realities as non-self. The jhana-factors are progressively abandoned as higher stages of jhana are attained. A high degree of panna is needed which discerns how to abandon the jhana-factors so that the higher stages of jhana which are more refined and tranquil can be reached. At the highest stage of rupa-jhana only the factors upekkha and samadhi are left (Vis. Ch IV). The arupavacara cittas (of arupa-jhana, immaterial jhana) are accompanied only by the jhana-factors upekkha and samadhi.
Jhana-factors which are sobhana condition each kusala citta, and thus they also condition the kusala citta which develops vipassana by way of jhana-condition. In vipassana the aim is not the suppression of the hindrances by the development of the sobhana jhana-factors, as is the case in samatha. Some people think that the hindrances have to be suppressed first before there can be right understanding of nama and rupa. In vipassana, however, right understanding is developed of whatever reality appears, also when that reality is a "hindrance". When it appears it does so because it is conditioned. All conditioned realities have to be known as they are, as non-self. At the moment of right understanding of the characteristic of a hindrance such as desire or ill will, the citta is kusala citta and there is no hindrance.
There is no rule that samatha should be developed before vipassana can be developed. Some people develop samatha, others do not, and this depends on conditions. People are born with different inclinations, different talents, different possibilities. Our life is an unbroken series of cittas and thus, inclinations can be accumulated from one moment to the next moment. The bhavanga-citta which succeeds the patisandhi-citta is conditioned by that citta by way of proximity-condition, anantara-paccaya, and each following citta is conditioned by the preceding one by way of proximity-condition. Cittas are conditioned by many different conditions and there is no self who could alter the cittas which arise.
Lokuttara cittas are conditioned by sobhana jhana-factors by way of jhana-condition. The jhana-factors are included in the enlightenment factors which perform their functions so that enlightenment can be attained. The magga-citta (lokuttara kusala citta) eradicates defilements in accordance with the stage of enlightenment which is attained. The jhana-factors condition the lokuttara citta to be steadfast and highly concentrated on the object which is nibbana. Thus, nibbana appears very clearly to the lokuttara citta and there is a high degree of calm. Some people who attain enlightenment have developed samatha and attained jhana, others have not attained jhana. Those who are proficient in jhana and also develop insight can take citta as object of insight; jhana is then the basis of insight. In that way they can become detached from the idea that jhanacitta is self. We read in the "Kindred Sayings" (III, Jhana Khandha-vagga, XXVIII, Kindred Sayings on Sariputta, §1, Solitude) about a conversation between Sariputta and Ananda. We read that Ananda said to Sariputta:
"Calm are your senses, friend Sariputta, clear and translucent the colour of your face. In what mood has the venerable Sariputta been spending this day?"
"Friend, I have been dwelling aloof from passions, aloof from things evil, with my thought applied and sustained (with vitakka and vicara) in first jhana, which is born of solitude and full of zest (piti) and happiness (sukha). To me thus, friend, the thought never came: 'It is I who am attaining first ,' or 'It is I who have attained first jhana,' or 'It is I who have emerged from first jhana.' "
"Surely for a long time have leanings to I-making, to mine-making and to vanity been well rooted out from the venerable Sariputta. That is why it occurs not to the venerable Sariputta: 'It is I who am attaining first jhana,' or 'It is I who have attained first jhana,' or 'It is I who have emerged from first jhana.' "
In the following suttas we read that Sariputta did not take the higher stages of rupa-jhana nor the stages of arupa-jhana for self.
For those who are proficient in jhana and attain enlightenment the lokuttara cittas can be accompanied by jhana-factors of the different stages of jhana, depending on the stage of jhana which was the basis of insight just before they attained enlightenment. Since there are five stages of jhana, the eight types of lokuttara cittas can be accompanied by jhana-factors of five stages of jhana, and thus there can be forty types of lokuttara cittas instead of eight types. The degree and the amount of the jhana-factors which condition a citta at a particular moment are variegated, and this is dependent on many different conditions.
As we have seen, those who are proficient in jhana, who have jhana as basis of insight, can attain enlightenment with lokuttara jhanacittas, lokuttara cittas accompanied by jhana-factors of the different stages of jhana. The magga-citta (path-consciousness) is followed immediately, in the same process, by its result, the phala-citta (fruition-consciousness), and then, after that process is over, other types of citta arise. However, phala-cittas which experience nibbana can arise again in other processes of citta, many times during their life. This is not possible for those who attained enlightenment but who were not proficient in jhana and did not have jhana as basis of insight. Thus we see that people have different accumulations. However, for all those who have attained enlightenment defilements are progressively eradicated depending on the stage of enlightenment one has attained. We should not have desire for the attainment of jhana. A high degree of panna is needed for the development of the jhana-factors so that jhana can be attained. The disciples of the Buddha who were able to do so had accumulated a high proficiency in samatha during many lives. Instead of wishing for something that cannot be reached we should pay attention to what can be done right now. We can develop right understanding of the realities which have arisen already because of their own conditions. This kind of understanding leads to the eradication of defilements and that is the goal of the Buddha's teachings.
Footnotes and references:
Jhayati in the sense of burning is derived from another root.
See §147 a and §397 a.
The citta and cetasikas arising together with them.
As explained in my Introduction, all dhammas can be classified in the Tripartite division of kusala dhammas, akusala dhammas and indeterminate dhammas (avyakata, neither kusala nor akusala). Indeterminate dhammas include: citta and cetasika which are vipaka or kiriya, rupa and nibbana.
See "Abhidhamma Studies", IV, Mental Constituents, 3, Factors of Absorption, by Ven. Nyanaponika.
Fine material jhana. The meditation subjects of rupa-jhana are still dependent on materiality, whereas the meditation subjects of arupa-jhana, immaterial jhana, are not.
Bodhipakkhiya dhammas, wholesome qualities which should be developed for the attainment of enlightenment.
At each of the four stages of enlightenment arise one type of lokuttara kusala citta and one type of lokuttara vipakacitta.
See my "Abhidhamma in Daily Life", Ch 23. As regards the four stages of arupa-jhana, they are accompanied by the same jhana-factors as those of the fifth stage of rupa-jhana, namely samadhi and upekkha.