dKon mchog 'jigs med dbang po's text is exemplary of the genre. It presents the principal tenets of Indian schools, both Buddhist and non-Buddhist, treating six renowned non-Buddhist schools very briefly and then focusing on the four Buddhist schools and their main sub-schools. In the order of their presentation (the list of Buddhist schools represents an ascent in order of estimation) these are:

1. NON-BUDDHIST SCHOOLS
   1. Vaiśeṣika (Bye brag pa) and Naiyāyika (Rig pa can pa) (Particularists and Logicians)
   2. Sāṃkhya (Grangs can pa) (Enumerators)
   3. Mīmāṃsā (dPyod pa ba) (Analyzers or Ritualists)
   4. Nirgrantha (gCer bu pa) (The Unclothed, better known as Jaina [rGyal ba pa])
   5. Lokāyata (rGyang 'phan pa) (Hedonists)

2. BUDDHIST SCHOOLS
   1. Hīnayāna (Lesser Vehicle)
      1. Vaibhāṣika (Bye brag smra ba) (Great Exposition School)
         1. 18 sub-schools

      2. Sautrāntika (mDo sde pa) (Sūtra School)
         1. *Āgamānusārin (Lung gi rjes 'brangs) (Following Scripture)
         2. *Nyāyānusārin (Rigs pa'i rjes 'brangs) (Following Reasoning)

   2. Mahāyanā (Great Vehicle)
      1. Cittamātra (Sems tsam pa) (Mind Only School)
         1. *Āgamānusārin (Lung gi rjes 'brangs) (Following Scripture)
         2. *Nyāyānusārin (Rigs pa'i rjes 'brangs) (Following Reasoning)

      2. Mādhyamika (dBu ma pa) (Middle Way School)
         1. Svātantrika (Rang rgyud pa) (Autonomy School)
         2. Prāsaṅgika (Thal 'gyur pa) (Consequence School)[page 175]

The division of Buddhist philosophy into four schools is itself largely an artificial creation. For instance, the so-called Vaibhāṣika school is, in fact, a collection of at least eighteen schools that never recognized themselves as belonging to a single, overarching school. Also, their tenets are so various (some prefiguring Great Vehicle schools) that it is extremely difficult to recognize tenets common to all eighteen; thus, rather than attempting to do so, the Tibetan doxographers set forth representative tenets as explained in the root text of Vasubandhu's Abhidharmakośa ("Treasury of Manifest Knowledge") (see Shastri, Poussin) as if these constituted the general tenet structure of such an overarching system, even though they are merely typical of assertions found in these eighteen schools. This pretended amalgamation of many schools into one is a technique used to avoid unnecessary complexity that might hinder the main purpose of this genre of exegesis—the presentation of an ascent to the views of systems considered to be higher. Hence, in the Vaibhāṣika school there is a wide variety of opinion, a wide range of views some of which differ greatly from the kind of short general presentation that dKon mchog 'jigs med dbang po gives. Strictly speaking, even the name "Vaibhāṣika school" should be limited to followers of the Mahāvibhāṣā, an Abhidharma text that was never translated into Tibetan.

Also, the division of the Sautrāntika school into those following scripture and those following reasoning is highly controversial. The former are said to follow Vasubandhu's own commentary on his Abhidharmakośa, in which he indicates disagreement with many assertions of the Vaibhāṣika school as presented in his own root text. The latter—the Proponents of Sūtra Following Reasoning—are said to be followers of Dignāga and Dharmakīrti who (despite the fact that Dignāga and Dharmakīrti do not assert external objects) assert external objects—objects that are different entities from the consciousnesses perceiving them. Again, neither of these groups saw themselves as sub-divisions of a larger school called the Sautrāntika.

Similarly, the two sub-divisions of the Cittamātra school are those following scripture, who depend on the writings primarily of Asaṅga and his half-brother Vasubandhu (after the latter converted to Asaṅga's system), and those following reasoning, who depend on what is accepted to be the main system of Dignāga's and Dharmakīrti's writings. Again, it is unlikely that these two [page 176] groups perceived themselves as being sub-schools of a larger school. Rather, the groupings are the results of later schematizations that are based on similarities between their systems but are committed to the accepted dictum that there are only four schools of tenets.

Also, the names of the two sub-divisions of the Mādhyamika school—the Autonomy school and the Consequence school—were, as is clearly admitted by Tsong kha pa and his followers, never used in India. Rather, these names were coined in Tibet in accordance with terms used by Candrakīrti in his writings. Thus, the very format of the four schools and their sub-divisions does not represent a historical account of self-asserted identities but is the result of centuries of classification of systems in India and Tibet. Its purpose is to give the scholar a handle on the vast scope of positions found in Indian Buddhism.

Given this situation, the format of four schools can be seen as a horizon that opens a way to appreciate the plethora of opinions, not as one that closes and rigidifies investigation. In Tibet, students are taught this fourfold classification first, without mention of the diversity of opinion that it conceals. Then, over decades of study, students gradually recognize the structure of such presentations of schools of thought as a technique for gaining access to a vast store of opinion, as a way to focus on topics crucial to authors within Indian Buddhism. The task of then distinguishing between what is clearly said in the Indian texts and what is interpretation and interpolation over centuries of commentary becomes a fascinating enterprise for the more hardy among Tibetan scholars. The devotion to debate as the primary mode of education provides an ever-present avenue for students to challenge home-grown interpretations, and affords a richness of critical commentary within the tradition that a short presentation of tenets does not convey.