This aside concerning Ābhidharmika Kṣaṇavāda is slightly off-topic, but IMO also very contextualizing of early Buddhist sectarianism. One final note and then I'll conclude.
There are actually more
than nine factors within the four kṣaṇas that make up a "single cognition" (or, as the Theravādins would put it, a single "mind-door process")
If the Theravādin traditions of Abhidhamma can be generally known as a "Southern school," then it follows that the Abhidharmas of the Sarvāstivādins, Mahīśāsakas, etc., can be considered, for the sake of comparison, as being of "Northern Schools."
In the Northern
Abhidharma traditions, generally speaking, all of the "universal caitasikas" participate in cognition (which should come as no surprise at all!)
. These take place during the four kṣaṇas outlined earlier. These "universals" feature in all cognition necessarily
. As such, this outline drawn from Abhidharmadīpa, Abhidharmāmṛta, and Kośakārikā serves as a "template" for even more complex sequences of cognitive kṣaṇas featuring factors that are, for instance, not present among the universals.
Sensory Cognition in 12 Factors and 4 Kṣaṇas
Note: (Sanskrit) Caitasika ||| (English) Translation* ||| Corresponding Kṣaṇa
*the "translations" given reflect the specific usage of these terms in the Abhidharmas, and do not necessarily reflect their usages in the sūtras and other EBTs.
apratisaṃkhyānirodha (this refers to the previous fading-away of a cognition)
1) 1) manasikāra ||| attention ||| arising of arising
2) 1⅓) ekāgratā(1) ||| focus ||| arising of the dharma
3) 1⅔) sparśa ||| touching ||| the dharma itself
4) 2) saṃjñā ||| (bare) perception ||| the abiding of abiding
5) 2⅓) vedanā ||| (threefold) hedonic tone ||| the abiding of the abiding(2)
6) 2⅔) cetanā ||| rumination ||| the abiding of the dharma
7) 3) adhimokṣa ||| resolution ||| the transforming of transforming
8) 3⅓) chanda ||| desire-towards-activity ||| the transforming of the transforming
9) 3⅔) prajñā ||| wisdom (as "association") ||| the transforming of the dharma(2)
10) 4) smṛti(1) ||| mindfulness ||| ceasing of ceasing
11 4⅓) ekāgratā(2) ||| focus(2) ||| ceasing of ceasing(2)
12) 4⅔) smṛti(2) ||| mindfulness(2) ||| the ceasing of the dharma
apratisaṃkhyānirodha (the past cognition fades away)
Only one phase of one cognition occupies each kṣaṇa. There are three caitasikas per kṣaṇa. As such, generally-speaking, two of three caitasikas will be unnoticed initially (in most cases) in the stream of perception. Of the 12 caitasikas outlined here, only sparśa, saṃjñā, vedanā, cetanā, prajñā, and smṛti are directly experienced as they unfold in real-time
as momentary processes. As the yogin becomes more experienced, more "smṛtis" occupy this sequence, and that which was unnoticed becomes an object of mindfulness.
Now, we've still got an issue here. That's six experiences for four kṣaṇas. That's not "allowed."
With regards to saṃjñā and vedanā (and cetanā), the solution is based in appeals to the scriptures.
(MN 43 Ven Sujāto translation from Pāli with Sanskrit parallels above, note how the Sanskrit adds "cetanā" to this list)
yā ca vedanā yā ca saṃjñā yā ca cetanā yacca vijñānaṃ saṃsṛṣṭā ime dharmā nāsaṃsṛṣṭā
vedanā yā ca saññā yañca viññāṇaṁ ime dhammā saṁsaṭṭhā no visaṁsaṭṭhā
Feeling, perception, and consciousness—these things are mixed, not separate.
It is argued that saṃjñā and vedanā (and cetanā) are experienced as "one" (this "one" being sometimes called "pratisaṃvedanā"
in later texts) and are only re-analyzed as separate subsequent to the experience of them. Their experience is always "saṃsṛṣṭa,"
or "commingled" or "mixed," even though one of them is threefold and the other is manifold and even though they are separable in many other ways.
So what happens, supposedly, the rest of the time
when we have these multiple caitasikas arising in a single kṣaṇa?
Some of these mental processes are considered "unconscious" or "involuntary" (as far as their experience is concerned) at the moment they unfold, because the mind is otherwise preoccupied during the kṣaṇa.
On the contrary, however, surely
we "experience" all of the caitasikas involved in momentary cognition? Yes, we do, according to this Northern tradition. How though?
Prajñā and smṛti, as caitasikas, function as "surveyors" of the present and past respectively. Generally speaking
, prajñā selects a possible object from the set of all present things, and smṛti selects a possible object from the set of all past things. What is referred to as "smṛti(1)"
above is smṛti in the modality referred to as anusmaraṇavikalpa ("recollection"). What is referred to as "smṛti(2)"
in the above is smṛti in the modality of saṃtīranavikalpa ("examination"). What is referred to as "ekāgratā(1)"
above is the modality of ekāgratā that is known as "cittasyaikāgratetyekālambanatā,"
or "the citta having one object (at a time)." That which is referred to as "ekāgratā(2)"
above is the modality of ekāgratā that is known as "samādhiḥ sarvacetasi bhavati,"
or "the samādhi that is 'all that is called to mind.'"
In the case of prajñā, its objects here are chanda and adhimokṣa. In the case of anusmaraṇavikalpa smṛti here, its objects are the memories of the experiences of (past) manasikāra and (past) ekāgratā. In the case of saṃtīranavikalpa smṛti, it has the additional special objects of present
cetanā and present
The full function of "smṛti," which is ubiquitous to all cognition in the Northern Tradition, is not outlined here. Outside of this direct context, prajñā and smṛti can
take other objects, according to the Northern Schools, but here they take only what is specified.
This isn't even the tip of the iceberg. We haven't even dealt with the wholesome universals, the defiled universals, the unwholesome universals, the occasional universals, and the indeterminate universals. All that we've outlined here is merely 1) the universals and 2) the dharma being experienced (which is found at the "contact/sparśa" stage)
Here below we will see an account of the soteriological
import of the kṣaṇas. Stressing soteriology in such a manner shows that this is not just scholasticism for the sake of complexity.
The below is an account of "Insight into the Four Noble Truths"
as understood according to the Northern Abhidharmas. This chart outlines what is otherwise-called "stream-entry" in Buddhism, as it was understood by most Sarvāstivādins, Mahīśāsakas, conceivably Mahāsāṃghikas as well, and any other of the various sects who believed in the "fivefold" Buddhist path. This "fivefold versus fourfold versus singular versus threefold versus eightfold" debate is a very old one in Buddhism (see Kv 20.5, Kv 18.5, etc.).
The fourfold path is Mahāsāṃghika-specific and applies only to Bodhisattvas. The threefold path is 1) śīla, 2) samādhi, and 3) prajñā. The eightfold path is well-known from the Pāli suttas and other EBTs and will definitely be the "mārgology" or "path-doctrine" most familiar to readers of this forum. Skipping that for the sake of not repeating what is already widely-known, we have the so-called "fivefold path." The Theravādins, in the Kathāvatthu, rejected this thesis of a "fivefold path" that various other sects believe in. For those who are not aware, the general fivefold division of the path to Bodhi is as follows: 1) saṃbhāra ("coming-together"), 2) prayoga ("implementation"), 3) darśana ("beholding" in the sense of "the beholding of the four truths"
), 4) bhāvanā ("cultivation"), and 5) aśaiksa (that which is "beyond learning").
Here is the Darśanamārga according to the Vaibhāṣikas:
Darśanamārga of 4 Cognitions with 16 Factors, or 4 Dharmas during 16 Kṣaṇas
Note: the "darśanamārga" is the Sarvāstivādin model of stream-entry as well as of the other Āryan fruits, up to Arhatva. On the darśanamārga, the yogin realizes the four truths, becomes an Āryan, and finally either 1) experiences a fleeting foretaste of Nirvāṇa, or 2) attains Nirvāṇa with residue and becomes either an Anāgāmin or an Arhat.
Duḥkhasatya Truth of Duḥkha
1) duḥkhe dharmajñānakṣānti
(receptivity to knowledge of the dharma [called] "duḥkha[satya"])
arising of arising + arising of duḥkhasatya + duḥkhasatya
2) duḥkhe dharmajñāna
(knowledge of the dharma [called] "duḥkha[satya"])
abiding of abiding + abiding of duḥkhasatya
(receptivity to subsequent knowledge concerning duḥkha)
transforming of transforming + transforming of duḥkhasatya
(subsequent knowledge concerning duḥkha)
ceasing of ceasing + ceasing of duḥkhasatya
Samudāyasatya Truth of the Origin
5) duḥkhasamudāye dharmajñānakṣānti
(receptivity to knowledge of the dharma [called] "duḥkhasamudāya[satya"])
arising of arising + arising of samudāyasatya + samudāyasatya
6) duḥkhasamudāye dharmajñāna
(knowledge of the dharma [called] "duḥkhasamudāya[satya"])
abiding of abiding + abiding of samudāyasatya
(receptivity to subsequent knowledge concerning duḥkha's origin)
transforming of transforming + transforming of samudāyasatya
(subsequent knowledge of duḥkha's origin)
ceasing of ceasing + ceasing of samudāyasatya
Nirodhasatya Truth of the Cessation
9) duḥkhanirodhe dharmajñānakṣānti
(receptivity to knowledge of the dharma [called] "duḥkhanirodha[satya"])
arising of arising + arising of nirodhasatya + nirodhasatya
10) duḥkhanirodhe dharmajñāna
(knowledge of the dharma [called] "duḥkhanirodha[satya"])
abiding of abiding + abiding of nirodhasatya
(receptivity to subsequent knowledge of duḥkha's cessation)
transforming of transforming + transforming of nirodhasatya
(receptivity to subsequent knowledge of duḥkha's cessation)
ceasing of ceasing + ceasing of nirodhasatya
Mārgasatya Truth of the Path
13) duḥkhapratipakṣamārge dharmajñānakṣānti
(receptivity to knowledge of the dharma [called] "the duḥkha-counteragent path")
arising of arising + arising of mārgasatya + mārgasatya
14) duḥkhapratipakṣamārge dharmajñāna
(knowledge of the dharma [called] "the duḥkha-counteragent path")
abiding of abiding + abiding of mārgasatya
(receptivity to subsequent knowledge of the duḥkha-counteragent path)
transforming of transforming + transforming of mārgasatya
(subsequent knowledge of the duḥkha-counteragent path)
ceasing of ceasing + ceasing of mārgasatya
As we see, insight into the four truths, for the Vaibhāṣikas, consists of dharmajñānas, which are realizations of "knowledges of [the four] dharmas [of the four truths]," anvayajñanas, "subsequent knowledges [that come after the realizations]," and "kṣāntis" or "receptivities" to these. Through the kṣāntis, one gains candidacy for these realizations, as well as for the subsequent wisdoms/knowledges that follow the realizations. Theravāda Buddhism is quite different, but also similar in many other ways.