The Abhidharmakośabhāṣya (Treasury of Metaphysics with Self-Commentary) is a pivotal treatise on early Buddhist thought composed around the 4th or 5th century by the Indian Buddhist philosopher Vasubandhu. This work elucidates the buddha’s teachings as synthesized and interpreted by the early Buddhist Sarvāstivāda school (“the theory that all [factors] exist”), while recording the major doctrinal polemics that developed around them, primarily those points of contention with the Sautrāntika system of thought (“followers of the scriptures”). Employing the methodology and terminology of the Buddhist Abhidharma system, the Abhidharmakośabhāṣya offers a detailed analysis of fundamental doctrines, such as early Buddhist theories of mind, cosmology, the workings of karman, meditative states and practices, and the metaphysics of the self. One of its unique features is the way it presents the opinions of a variety of Buddhist and Brahminical schools that were active in classical India in Vasubandhu’s time. The work contains nine chapters (the last of which is considered to have been appended to the first eight), which proceed from a description of the unawakened world via the path and practices that are conducive to awakening and ultimately to the final spiritual attainments which constitute the state of awakening. In its analysis of the unawakened situation, it thus covers the elements which make up the material and mental world of sentient beings, the wholesome and unwholesome mental states that arise in their minds, the structure of the cosmos, the metaphysics of action (karman) and the way it comes into being, and the nature of dispositional attitudes and dormant mental afflictions. In its treatment of the path and practices that lead to awakening, the treatise outlines the Sarvāstivāda understanding of the methods of removing defilements through the realization of the four noble truths and the stages of spiritual cultivation. With respect to the awakened state, the Abhidharmakośabhāṣya gives a detailed description of the different types of knowledge and meditational states attained by practitioners who reach the highest stages of the path.
The Indian Buddhist philosophers Dignāga (c. 480–540 ce) and Dharmakīrti (c. 600–660 ce) decisively influenced the course not only of Buddhist philosophy, but of Indian philosophy more generally. Having inherited an earlier philosophical tradition (the one advanced in the Buddhist Abhidharma literature) that had been largely intramural in character, Dignāga and Dharmakīrti fundamentally transformed Buddhist philosophy by advancing basically similar commitments with arguments meant to be persuasive across party lines. In doing this, they influentially theorized a family of concepts largely shared by all Indian philosophers writing in Sanskrit—a family centering on the concept of pramāṇa, which denotes a reliable way of knowing or epistemic “criterion” (as one might translate the word)—in ways that facilitated an unprecedented extent of debate among Indian philosophers of all sorts. The resultant growth in the sophistication of philosophical traditions is one of the most salient features of the mature period of classical Indian philosophy. Though there are significant differences between them, Dignāga and Dharmakīrti commonly argued in terms of a broadly empiricist sort of epistemology; this was advantageous insofar as that involves premises to which they might readily win assent, while nonetheless being conducive to the philosophical idealism they both finally upheld. Committed as they were to the basically empiricist notion that only perceptibles are finally real, both thinkers affirmed versions of the innovative sort of nominalism first introduced by Dignāga (and significantly revised by Dharmakīrti): the elusive apoha (“exclusion”) theory of meaning, which represents one of the Buddhist tradition’s signal contributions to the history of Indian philosophy. While some of Dignāga’s works were translated into Chinese and thus became influential in East Asia, none of Dharmakīrti’s was; in both India and Tibet, however, Dharmakīrti effectively eclipsed his predecessor. For generations of subsequent Indian philosophers, Dharmakīrti practically epitomized “the Buddhist position” in matters philosophical, and his works figure to this day as central to most Tibetan monastic curricula.
Abhidharma had its origin in certain systematizing, analytical, and exegetical features found in the Sūtra, particularly, mātṛikā (summary list), abhidharma-kathā (discussion about the doctrine), vibhaṅga (“analytical exposition”), and upadeśa (exegetical elaboration). Buddhist philosophies may have been primarily initiated and vigorously elevated in the Abhidharma tradition. However, while the Abhidharma treatises undoubtedly exhibit highly developed scholastic and hermeneutical components, Abhidharma is essentially a soteriology. The Sarvāstivāda Ābhidhārmikas consistently claim that Abhidharma is truly “Buddha-word,” being the sine quo non for ascertaining the true intents of the sutras—it constitutes the ultimate authority for discerning the definite and explicit discourses (nītārtha-sūtra) of the Buddha. Sarvāstivāda, the “All-exist School,” was undoubtedly one of the most important Buddhist schools in the period of Abhidharma Buddhism. Since its establishment around the 2nd century bce, it exerted tremendous impact, directly or indirectly, on the subsequent development of Indian Buddhism. This school possesses a complete set of seven canonical Abhidharma texts, nearly all of which are now preserved in Chinese translation, and one, the Prajñapti-śāstra, is preserved in a complete Tibetan translation. A huge compendia, The Great Abhidharma Commentary (Abhidharma-mahāvibhāṣā), whose gradual compilation must have spanned over more than half a century and was fully completed around 150 ce, is now extant only in Chinese. This compendia, encyclopedic in scope, defines the doctrinal positions of the orthodox Sarvāstivādins based in Kaśmīra, who subsequently came to be known as the Vaibhāṣikas. The central thesis of the school is sarvāstivāda or sarvāstitā (/sarvāstitva), which claims that all “dharmas”—fundamental realities or real entities of existence—sustain their unique intrinsic natures throughout the three periods of time. That is, whether future, past, or present, a dharma’s intrinsic nature remains the same, even though its mode of existence (bhāva) varies. This thesis was vehemently challenged by the Vibhajyavādins (Distinctionists) who denied the reality of the past and future dharmas. The reverberation of this “Sarvāstivāda-versus-Vibhajyavāda” controversy can be observed to have generated decisively significant doctrinal implications throughout the history of Buddhist thoughts. The Savāstivāda school was also known as Hetuvāda, a “school which expounds on causality.” Kātyāyanīputra (c. 150 bce), often regarded as the effective “founder” of the Sarvāstivāda school, was credited with the innovation of a theory of sixfold causes, of which the coexistent or simultaneous causality was the most important legacy. For the first time in human history, he systematically articulated a form of causality in which the cause and its effect coexist simultaneously. This theory contributed importantly to Buddhist doctrinal development, particularly its epistemology. Mahāyāna Yogācāra had embraced it from their very inception, finding it indispensable for the establishment of many of their fundamental doctrines, including “store consciousness” (ālaya-vijñāna) and “cognition-only” (vijñaptimātratā).