As we have said, the course of bsdus grwa can be divided into the following three stages: bsdus grwa (in the narrow sense), blo rigs and rtags rigs. Roughly speaking, these three treat of ontology, epistemology and logic, respectively. This threefold classification is sometimes expressed as the study of "objects" (yul), "subjects" (yul can), and "the ways to cognize objects" (yul de rtogs pa'i tshul). The precise contents of bsdus grwa texts are not completely uniform, but these texts do nonetheless share a corpus of principal subjects or "lessons" (rnam bzhag).

Let us now briefly examine the contents of bsdus grwa, blo rigs and rtags rigs by focusing on a few representative subjects. The first stage of the primary course is bsdus grwa in its narrow sense, generally comprised of three lessons. The first, which is common to all colleges, is known as "kha dog dkar dmar," which literally means "white and red colors." Some colleges even assign a separate class ('dzin grwa) to the subject. At this stage, students learn [page 189] about the notion of pervasion or entailment (khyab pa), as occurs, for example, between white color and color itself—the former entailing the latter. Similarly, students learn to differentiate between general propositions involving pervasions, such as "whatever is red must be a color" (dmar po yin na kha dog yin pas khyab), and those involving specific topics (chos can), such as "take as the topic, red; it is a color" (dmar po chos can kha dog yin) (see Tillemans: 286).

In the next class, called gzhi grub (literally, "established bases"), students are introduced to some ontological notions construed more or less in accordance with the system of the Indian Sautrāntika school, especially as it is portrayed by Dharmakīrti. Here again, students pay special attention to the inclusions and differentiations holding among the key concepts.

After completing this initial class, students proceed to the next, where they learn more abstract and theoretical notions. At this level, schemata necessary for logical thinking such as concept (ldog pa, literally "isolate"), cause and effect (rgyu dang 'bras bu), genus and species (spyi dang bye brag), relations and contraries ('brel ba dang 'gal ba) and definition and definiendum (mtshan nyid dang mtshon bya) are introduced and examined.3 In the last class of this first stage, students learn to use the thal 'gyur (prasaṅga) argumentation form, i.e., "consequences" or "reductio ad absurdum" (see Onoda, 1986, 1988) and other logical operators such as "implicative negations" and "non-implicative negations" (ma yin dgag dang med dgag). In short, the purpose of this first stage, i.e., bsdus grwa as more narrowly conceived, is not only to introduce students to basic theoretical schemata, but also to allow them to acquire the practical mastery of debating techniques which will be indispensable for more advanced dialectical study.

When a student has finished the initial stage of bsdus grwa classes, he is allowed to proceed to the next stage, i.e., blo rigs, which is largely concerned with epistemological matters. The main subjects are the classifications of cognition in terms of "valid and invalid means of cognition" (tshad ma dang tshad min), "conceptual and non-conceptual cognition" (rtog pa dang rtog med), "self-awareness and other-awareness" (rang rig dang gzhan rig) and "mind and mental factors" (sems dang sems byung). These classifications in turn frequently admit of sub-classifications. For example, invalid means of cognition (tshad min) is divided into five: subsequent cognition (dpyad shes), true presumption (yid dpyod), inattentive cognition (snang la ma nges pa), doubt (the tshom), and erroneous [page 190] cognition (log shes). Valid means of cognition (tshad ma) is divided into two: direct perception (mngon sum gyi tshad ma) and inference (rjes su dpag pa'i tshad ma). It should be noted that this type of sevenfold division of cognition (blo rigs bdun du dbye ba) is said to have originated with Phya pa Chos kyi seng ge (1109-1169) (see van der Kuijp, 1979).

The last stage, rtags rigs (see Onoda, 1981), introduces an Indian type of logic centered around the elaboration of the threefold criteria—the so-called tshul gsum (or trairūpya)—which enables one to distinguish between correct, or valid, logical marks (rtags yang dag) and those which are invalid, or more literally are pseudo-marks (rtags ltar snang).

These three types of texts—bsdus grwa, blo rigs and rtags rigs—teach students the practical applications of disputation or debate (rtsod pa). One of the main reasons why adepts of such a training are called mtshan nyid pa is that they pay special attention to terms and definitions (mtshan nyid), memorizing them and analysing them for inconsistencies, insufficiencies and redundancies. A further reason as to why this preliminary training is so indispensable is that the school manuals (yig cha) for advanced classes such as Prajñāpāramitā and Madhyamaka are written in the special style and format which we find in bsdus grwa texts. This format, where arguments are presented largely by means of prasaṅgas (thal 'gyur), was christened thal phyir, or "sequence and reason," by Stcherbatsky (55), who maintained that it probably had its origins with Phya pa Chos kyi seng ge (see Jackson, 1987: 152, n. 28; cf. van der Kuijp, 1983: 294, n. 220).