Eighteen Schools of Early Buddhism

Eighteen Schools of Early Buddhism. As Buddhism spread throughout India, a diversity of schools developed over the first 400 years, some based on major doctrinal differences and others merely as regional variants. Retrospectively, various Mahāyāna scholar-monks determined that there were eighteen of these schools, although their accounts of the relationship and differences between them are not consistent. One simple classification, acording to Vinītadeva, has the following four major schools with their offshoots: (1) Sthavira, and the Jetavanīyas, Abhayagirivāsins, and the Mahāvihāravāsins; (2) Mahāsaṃghika, and the Pūrvaśailikas, the Aparaśailikas, the Lokottara-vāda, and the Prajñaptivāda; (3) Sarvāstivāda, and the Kāśyapīyas, Mahīśāsakas, Dharmaguptakas, and the Mūla-sarvāstivādins; and (4) Saṃmitīya, and the Kaurukullaka, Avantaka, and Vātsīputrīya. Vinītadeva's list, however, is late and not altogether reliable. For example, the Sthaviras did not exist as a school separately from the three nikāyas mentioned in group (1), and the same was probably true of the Mahāsaṃghikas and Saṃmitīyas. In group (3), the Sarvāstivādins and Mūla-sarvāstivādins were arguably the same school. The Dharmaguptas and Kāśyapīyas were probably not extant in India in Vinītadeva's day, and the Mahīśāsakas only in a Mahāyāna/Sarvāstivāda influenced form. Mention of these three schools in earlier Sarvāstivādin works led Vinītadeva to classify them in this historically incorrect form. Too much reliance should therefore not be placed on the traditional classifications of the eighteen schools.