Citta are differentiated by the kinds of sankhara as asankharika and sasankharika.

The word sankhara in the Tipitaka has several meanings comprising

1  sankhara-dhamma.
2  sankhara-khandha.
3  abhisankhara.
4  asankharika and sasankharika.

Sankhara-dhamma is the reality that arises because of paccaya or conditions composing it.  When it arises it falls away. Sankhara-dhamma are not permanent.  They arise only the shortest instant and then fall away completely.

 Sankhara-dhamma are namely citta, cetasika and rupa.

The 4 paramattha-dhamma are citta, cetasika, rupa and nibbana, the first three of which are sankhara-dhamma arising from the composition of paccaya to exist and then fall away after a very short instant.  There are no conditions for nibbana, therefore it is the reality that does not arise or fall away, it is visankhara-dhamma.

The 3 sankhara-dhamma or citta, cetasika and rupa are categorized as the five-khandha, as follows
 

1.  All rupa                                    are rupa-khandha.
2.  The vedana-cetasika               is vedana-khandha.
3.  The sanna-cetasika                 is sanna-khandha.
4.  The 50 remaining cetasika      are sankhara-khandha.
5.  All citta                                    are vinnana-khandha.

Therefore sankhara-khandha are the 50 cetasika excluding vedana-cetasika and sanna-cetasika. Sankhara-dhamma comprises all the 89 citta, all the 52 cetasika and all the 28 rupa.

The meaning of sankhara-dhamma is more comprehensive than sankhara-khandha because citta, cetasika and rupa are all sankhara-dhamma while only the 50 cetasika are sankhara-khandha.  And out of the 50 cetasika, which are sankhara-khandha, only cetana-cetasika is abhisankhara.  In the paticcasamuppada, avijja is paccaya for sankhara, sankhara is paccaya for vinnana etc.  Sankhara in the paticcasamuppada means cetana-cetasika, which is abhisankhara, the supreme composing reality, or kusala-kamma, or akusala-kamma which would result in vipaka-citta and -cetasika.  Even though other cetasika also condition citta to arise such as phassa-cetasika.   Without phassa-cetasika, which is a reality that comes into contact with arammana, there can be no citta that sees, hears, smells, tastes, knows bodysense contact or thinks.  But phassa-cetasika is still not abhisankhara because it only comes into contact with arammana and then is gone.

 Therefore of 50 sankhara-khandha only cetana-cetasika is abhisankhara, or reality that is supreme in conditioning or composing by being kusala-kamma or akusala-kamma as kamma-paccaya that results in vipaka-cetasika's arising.

 There are 3 sankhara in the paticcasamuppada:
1 punnabhisankhara,  2 apunnabhisankhara  3 anenjabhisankhara.
 Punnabhisankhara being cetana-cetasika that arises with kamavacara-kusala-citta and rupavacara-kusala-citta.
 Apunnabhisankhara being cetana-cetasika that arises with akusala-citta.
 Anenjabhisankhara being cetana-cetasika that arises with arupajhana-kusala-citta, which is a steadfast, imperturbable kusala.

 Kamavacara-kusala-citta can only arise for short, little instants and easily disturbed because they arise only in processes with series of 7 citta.  Dana, the abstention from dishonesty and other developments of kusala would arise only occasionally.  Other than that akusala-citta would arise in numerous processes. Rupavacara-kusala-citta is kusala-nana-sampayutta composed of panna-cetasika, or cetasika that is peaceful enough to attain the level of appana-samadhi with rupa as arammana.  It, therefore, is a mahagghata-citta that is close to kamavacara-kusala because it still has rupa as arammana.  Anenjabhisankhara is an arupajhana or the pancama-jhana with no rupa as arammana.  That instant of citta is steadfast because there is no rupa as arammana so that the result is plenary which is to make arupajhana-vipaka-citta arise in the arupa-brahma-bhumi where life is very long according to the power of the arupajhana-kusala.  To be born in heaven is happiness because there are no such diseases, hardships or physical sufferings as there are in human and apaya-bhumi.  But life there is not as long as in the rupa-brahma-bhumi and that of the rupa-brahma-bhumi is not as long as life in the arupa-brahma-bhumi because the arupa-brahma-bhumi is the result of arupajhana-kusala, which is anenjabhisankhara.

 Sankhara-dhamma comprises citta, cetasika and rupa.

 Sankhara-khandha comprises the 50 cetasika excepting vedana-cetasika and sanna-cetasika.

 Abhisankhara is the cetana-cetasika (one of the 50 sankhara-khandha).

Differentiation among citta according to the kinds of asankharika and sasankharika shows that the kusala-, akusala-, vipaka- or kiriya-citta that arise with cetana-cetasika also differ into 2 kinds.  Some are asankharika and others sasankharika. In the Atthasalini Cittuppadakandha there is a passage explaining: called sasankhara because it evolves with sankhara (inducements).  Sankhara in this context means self-induced or induced by others, or ordered to perform.  This is the characteristics of citta in everyday life, whether it were kusala or akusala, it would arise by itself with the strong paccaya of past accumulations without inducements of any kind.  This conditioned citta which arises without inducement is asankharika, or does not rely on inducements.  Sometimes, however, whether it were kusala or akusala, it would arise weakly, only able to arise by relying on inducement from itself or from other people.  The kusala or akusala of little strength, which relies on inducement to arise, is sasankharika-citta.

This shows that even kusala or akusala are differentiated by the strength accumulated in itself as paccaya to arise and sometimes by the weakness and dependence on inducement of itself or from others to arise.

Akusala-citta sometimes arises immediately according to accumulations, to be pleased or not with the arammana at the time.  Sometimes it is not so.  For example, one does not want to go to the cinema or plays but when friends and relatives ask one to, one does.  Does that instant of citta want to go?  Just as soon go as not.  But since someone asks, one goes.  By oneself one would not.  Or sometimes one thinks that the movie might be entertaining so one would like to see it but one does not go because the desire is not strong enough to go right away.  In real daily life one can see which instant the citta is strong and when weak whether of the akusala-type, that is lobha and dosa, or of the kusala-type.  Some people when they heard of robe-offering ceremonies, they wish to join immediately as well as ask others to join in.  Others, even though they are asked, could not join if this or that person won't.  Therefore aspects of kusala-citta and akusala-citta differ according to paccaya, or causes, that condition the arising and evolving of the instant, even though the cetasika that compose the citta are of equal numbers.

 The Buddha manifested the asankharika and sasankharika so that we may see the minute details of citta: though citta may have the same number of cetasika in its composition, without variation, the aspects of citta differ into asankharika and sasankharika according to the strength of the cetasika arising with it.  To demonstrate the great beneficent karuna of the Buddha, who has the great kindness in manifesting the dhamma minutely, the Atthasalini Atthakatha Dhammasangipagana Cittuppadakandha explains "ananta" or the 4 greatest expanses [infinity] as follows:
  These are considered the 4 "ananta", being 1 akasa (space) is ananta, infinite; 2 the universe is ananta, infinite; 3 the sattanikaya (species of animals and entities) is ananta, infinite; 4 the Buddha-nana (the Buddha's omniscience) is ananta, infinite.

 Truly it is not possible to calculate akasa to the north, south, east or west to be so many hundred or thousand yojana. (...)  If one were to use an iron hammer as big as the sineru mountain to pound the earth in two and then toss the iron hammer in the space between, it would truly fall below.  There would be nothing to restrain it.  Called ananta, the akasa is infinite, thus.

 To calculate the universe as so many hundred, thousand or hundred thousand in number is impossible.  Truly, if the four great Brahma born in the Akanittha-plane (the rupa-brahma-bhumi of the fifth level of the Sudhavasa, which is the highest level) who are so swift that they could pass ten thousand universes in the time it take an arrow of an archer of great strength to pass the shadow of the sugar-palm crosswise, were to run with such speed, thinking we shall see the edges of the universe, these great Brahma are certain to attain parinibbana before ever having done so.  All the universes are thus called ananta, infinite.

 To calculate the number of aquatic and land animals in the universe is impossible. Sattanikaya is thus called ananta (infinite).

 The Buddha-nana is said to be more ananta than all the three ananta above together.

 Akasa we can see is endless.  None can measure how many hundred, thousand or hundred thousand yojana it is.  Nor can one measure the universe, who wants to count stars, universes?  One can never succeed because the universe is ananta, infinite.  Even sattanikaya, or all the life forms of the universe, cannot be counted or made into statistics, humans, deva, Brahma, land animals, aquatic animals, animals in apaya.  Still the Buddha-nana is said to be more ananta than all three: the innumerable beings, the boundless universe and the immeasurable space.

 (Considering the incalculably infinite number of entities in the universe, the citta of these entities must be very intricately different indeed.)

  The kusala-citta that is kamavacara somanassasahagata (arising with somanassa-vedana) nana-sampayutta and asankharika (arising spontaneously, without inducement) would arise in each entity in great numbers, since there are great numbers of entities, citta would proportionately arise in greater numbers.

 There is not one unique kusala-citta. Even the kusala-citta of the kamavacara-kusala kind arising with panna or, as nana-sampayutta, and asankharika, or with great strength, is not only of one kind.  Citta must vary according to the numbers of entities, which each has citta that arise one at a time.  Though the citta arise as numerously as the number of entities, but all kusala-citta are of the same type: by definition they are kamavacara, somanassasahagata, nana-sampayutta and with the common status of asankharika.

 The Sammasambuddha can determine the kamavacara-kusala-citta that arise with all the entities of incalculable numbers in all the universes of incalculable extent with his omniscience as if he weighed them on a great scale and measured them in bushels.  Then he arranged them into 8 parts and manifested that these citta (kamavacara-kusala-citta) are of 8 kinds, with the explanation of which the pundits could only agree (they could not deny it).

 This shows that as numerable as kamavacara-kusala-citta may be the Buddha could count and organize kamavacara-kusala into 8 kinds of mahakusala which no one can deny through the differences in the upekkha- or somanassa-vedana in the arising of panna or the absence thereof and in being asankharika or sasankharika.

 Therefore the 8 kamavacara-kusala-citta or mahakusala-citta are:

 Somanassa-sahagatam     nana-sampayuttam     asankharikam
 Somanassa-sahagatam     nana-sampayuttam     sasankharikam
 Somanassa-sahagatam     nana-vippayuttam       asankharikam
 Somanassa-sahagatam     nana-vippayuttam       sasankharikam
Upekkha-sahagatam          nana-sampayuttam     asankharikam
Upekkha-sahagatam          nana-sampayuttam     sasankharikam
Upekkha-sahagatam          nana-vippayuttam       asankharikam
Upekkha-sahagatam          nana-vippayuttam       sasankharikam

Have you ever been sleepy, tired or bored?  Sometimes the citta have the idea of doing some kusala or other, but then grow weak or sleepy.  Would sati be aware of the characteristics of that instant of citta.  If not, then it becomes the self, with real sleepiness, discouragement, disheartenment and boredom.  Weariness is real and if sati were not mindful of the characteristics of these realities as they truly are, there can be no knowledge of that reality as not an entity, a person or the self but only the characteristic of the citta that arises from conditions and causes and then falls away. The Buddha manifested different kinds of citta, for example, asankharika and sasankharika: there are lobha-mula-citta that are asankharika while others are sasankharika; there are dosha-mula-citta that are asankharika and sasankharika; likewise kusala-citta.  Whenever sati is mindful of the characteristics of these realities, there can be knowledge that they are nama-dhamma and not rupa-dhamma.

 Discouragement, disheartenment are not rupa but realities of citta that are sasankharika because they are citta that are not strong.

 Only the kamavacara-citta differ into asankharika and sasankharika because the kamavacara-citta is the citta of the lowest bhumi, the citta of the kind that arises commonly in daily life at every instant of seeing, hearing, smelling, tasting, knowing bodysense contact and thinking about sight, sound, smell, taste and bodysense contact.  Sometimes they are strong, others weak according to causes and conditions.  But citta of higher levels, such as the rupavacara-citta, arupavacara-citta or lokuttara-citta, are not differentiated as asankharika or sasankharika because by nature they are all sasankharika with the definition that these citta cannot arise by themselves but depend on development of the distinct citta to arise, unlike the kamavacara-citta that differ into strong citta and weak citta.  This is because, for the rupajhana-kusala-citta, arupajhana-kusala-citta or lokuttara-kusala-citta to arise, the kamavacara-kusala-nana-sampayutta-citta must have arisen previously.  Without the development of kamavacara-kusala-nana-sampayutta-citta as inducement, the jhana-kusala-citta or lokuttara-kusala-citta cannot arise at all.  Therefore citta of other bhumi, or rupavacara-citta, arupavacara-citta and lokuttara-citta, are all sasankharika and nana-sampayutta without exception.

 Each would be able to know the characteristics of asankharika- and sasankharika-citta of one's own.  For example, do those who come to listen to the dhamma depend upon the inducement of others?  At first maybe there was no desire to come but someone persuaded them to.  But afterwards they come by themselves.  The characteristics of the citta of those that came by themselves differ from those with inducements.  Not that there is always sasankharika or only asankharika.  As in those who were asked to go to a cinema.  When asked, the citta was weak.  But if the movie was entertaining, exciting, they laughed, enjoyed it and at that instant the citta was no longer weak.  No one induced them to laugh and have fun.  But the citta of that instant was strong and arose with somanassa- vedana so there was enjoyment and laughter and therefore the citta is asankharika.  This demonstrates the characteristic of anatta of each instant of citta that arises and evolves according to conditions.  Even though now it is so, the next instant it can be another way according to causes and conditions.

1.  What are sankhara-dhamma, sankhara-khandha, abhisankhara, asankharika and sasankharika?
2.  How are the 8 lobha-mula-citta and the 8 mahakusala-citta alike?
     How do they differ?