Chapter 6 The Decline and Disappearance of Indian Buddhism: Inferences from Historical Sources¶

Indian Buddhism arose in the fifth century BCE and reached its height under Aśoka in the third century BCE. Its intellectual peak came in the Nālandā era, from the fifth to the twelfth century. In the early thirteenth century, it almost completely disappeared from the South Asian subcontinent. A religious tradition of nearly seventeen hundred years all but vanished within a relatively short time. Such an event is rare in world religious history.

This chapter asks why. There is no simple answer. The most common explanation, "Islamic invasion," compresses a complex historical process into a dramatic event. Yet Indian Buddhism was already in deep decline long before the Islamic armies arrived. This chapter presents the factors separately and then offers the book's overall judgment.

I. How to Frame the Question¶

Is "decline and disappearance" accurate?

The terms need scrutiny. "Decline and disappearance" suggests a linear process from flourishing to extinction. Indian Buddhism's actual history is more complex. It did not suddenly vanish one day; it contracted slowly over centuries. It lasted longer in some regions and declined earlier in others. Some elements—techniques of practice, philosophical concepts, and deity images—were absorbed into Hinduism and survived in altered forms. A distinctive Buddhist tradition persists to this day among Nepal's Newar communities.

It is therefore more accurate to speak of its "disappearance from the Indian subcontinent as a recognizable, independent religious tradition" than of its complete extinction.

The limits of the sources

An unavoidable difficulty for this chapter is that Indian Buddhism's decline occurred precisely during a period with exceptionally sparse documentary records. After the thirteenth century, Buddhist scholars in India almost ceased to exist, leaving insufficient accounts from within the tradition. We rely mainly on external sources—Chinese accounts, records of Muslim conquerors, and archaeological evidence—and later retrospective inferences. Accounts of the decline are therefore substantially constructed by historians reasoning from limited evidence, rather than directly recorded facts. The subtitle "Inferences from Historical Sources" reminds readers of this epistemological premise.

II. A Timeline of Decline: Regional Differences¶

Buddhist decline did not occur simultaneously throughout India. Its marked regional differences are crucial to understanding its causes.

South India: the earliest decline

Buddhism's decline in South India occurred roughly in the seventh to ninth centuries, long before Islamic forces arrived. When Xuanzang visited India in the early seventh century, he already recorded falling Buddhist numbers and abandoned monasteries in many parts of the south.¹ By the eighth and ninth centuries, Śaivism and Vaiṣṇavism were South India's dominant religions, leaving Buddhism scarcely any foothold.

The decline in this region had nothing to do with Islamic invasion. Most of South India did not begin to experience substantial influence from Muslim powers until the twelfth century. Buddhist decline there resulted entirely from internal factors and competition from Hinduism.

Northwestern India: already under assault in the seventh century

Buddhism in northwestern India—present-day Pakistan and Afghanistan, including ancient Gandhāra, Kashmir, and neighboring regions—suffered attacks from the Hephthalites (Huna, White Huns) and early Muslim invasions in the seventh century and began to contract markedly. Xuanzang recorded many abandoned monasteries in the northwest during his travels.

Eastern India: the last stronghold

Sustained Pāla patronage (c. 750–1174) made Bihar and Bengal the regions where Indian Buddhism lasted longest. They also suffered the most direct final blows from Islamic armies under Bakhtiyar Khilji, around 1193–1203. Pāla decline, culminating in the dynasty's fall in 1174, had already deprived Buddhism of institutional support. The military assaults struck a tradition that was already substantially weakened.

III. Internal Factor One: Monastic Structure and Detachment from Society¶

Institutional vulnerability

As 8.5 noted, middle and late Indian Buddhism depended heavily on the monastic system, which in turn depended on state patronage. This contrasted sharply with early Buddhism's alms system, in which monks depended on daily lay offerings and maintained a widespread presence among ordinary people.

Nālandā's monks lived on state tax revenues, reducing their daily contact with ordinary people. Monastics became a professional scholarly class, separated from the wider lay community by a much greater distance than in early Buddhism. A major mechanism of early Buddhist transmission—monks teaching people while on alms rounds, and people sustaining monks through daily offerings—was greatly weakened in the age of the great monasteries.

The lack of institutions rooted in popular life

Buddhism lacked the deep roots in popular society that Hinduism maintained through its temple system. Hindu temples were centers of local community life as well as religious sites, organizing festivals, weddings, funerals, and agricultural rituals. Their Brahmin priests provided ritual services at the important moments of life: birth, coming of age, marriage, and death.

Buddhist monasteries chiefly served monastic practice and did not provide equivalent institutional services for laypeople's everyday rituals. When state patronage disappeared, Buddhism therefore lacked an alternative support base rooted in ordinary communities. Hindu temples, by contrast, could continue through villagers' voluntary upkeep even without royal patronage.

IV. Internal Factor Two: Blurred Boundaries with Hinduism¶

The blurring caused by the turn toward Tantra

From about the seventh century, as Vajrayāna flourished, Indian Buddhism increasingly resembled Hinduism outwardly, especially Śaiva Tantra. Both had deity images, maṇḍalas, mantras, secret rites, and guru lineages. Believers unfamiliar with the doctrines found it very difficult to distinguish Buddhist Tantra's wrathful protectors, such as Mahākāla, from Śaiva deities.

This blurring had effects in both directions. Buddhist Tantra borrowed techniques from Śaiva Tantra, increasing its appeal to some believers. Yet the resemblance also allowed believers to "turn" from Buddhism to Hinduism with scarcely any sense of fundamental change. If an ordinary believer thought Mahākāla could receive offerings in either tradition, there was no compelling reason to retain a "Buddhist identity."²

Hinduism's incorporation of the Buddha

Hinduism made the Buddha Viṣṇu's ninth incarnation (avatāra). On the surface, this "recognized" the Buddha; in substance, it incorporated him into a larger Hindu theological framework and removed the need for Buddhism as an independent tradition. If the Buddha is Viṣṇu's incarnation, why is a separate religion called "Buddhism" still necessary?

Śaṃkara's philosophical competition with Buddhism

At the philosophical level, the Advaita Vedānta of Ādi Śaṃkara (c. 788–820) was the period's most important Hindu philosophical system and its most systematic philosophical response to Buddhist thought.

Overview of his writings

Śaṃkara's writings fall into commentaries and independent works. The central commentary is the Brahmasūtra-bhāṣya, which contains his systematic critiques of the Buddhist schools. Other commentaries cover ten principal Upaniṣads, including the Bṛhadāraṇyaka, Chāndogya, and Taittirīya, and the Bhagavad Gītā. Among independent works, the Vivekacūḍāmaṇi (Crest-Jewel of Discrimination) and Ātmabodha (Knowledge of the Self) are widely read; they describe a path of practice from discriminative knowledge to liberation.³ The attribution of these works needs qualification. An enormous number of texts are traditionally attributed to Śaṃkara, and the authorship of many remains disputed. Some very likely came from later disciples.

The central claims of nondualism

Śaṃkara's basic framework can be summarized in three points. First, Brahman is the sole ultimate reality, an indivisible unity of pure consciousness (cit), existence (sat), and bliss (ānanda). Second, Ātman, the individual's true self, is essentially nondual with Brahman. The Chāndogya Upaniṣad's "You are that" (tat tvam asi) directly expresses this relation. Third, the world's manifold appearances are a "superimposition" (adhyāsa) produced by ignorance (avidyā): mistaking the non-self for the self and superimposing differences and objects upon Brahman, as a snake is superimposed upon a rope. The striking resemblance to the rope-and-snake analogy in Yogācāra's three-nature theory is not accidental. This book holds that Śaṃkara studied Madhyamaka and Yogācāra deeply and indeed drew on them. Liberation (mokṣa) consists in removing superimposition through correct knowledge (jñāna) and recognizing that the self has always been Brahman. No fabrication is required, only knowing and seeing things as they are.

Critiques of the Buddhist schools

Chapter 2, Section 2 of the Brahmasūtra-bhāṣya (2.2.18–32) specifically refutes Buddhist traditions, identifying them school by school.

Against Sarvāstivāda: the school holds both that external objects really exist and that the consciousness knowing them arises and ceases momentarily. Śaṃkara asks how a consciousness that perishes in one moment can know an external object existing in another. Without a unified cognizing subject spanning the two moments, Sarvāstivāda realism loses coherence.

Against Sautrāntika: the school says that we know only the "cognitive forms" appearing in consciousness and infer external objects. Śaṃkara pushes the reasoning a step further. If external objects can only be inferred, and the basis of inference is cognitive forms, that is, consciousness, positing external objects is superfluous. This argument pushes Sautrāntika toward a Yogācāra position it does not wish to accept.

Against Yogācāra, or consciousness-only thought: Śaṃkara concentrates on two points. First, "consciousness-only" as a claim itself requires a cognizer. When one says "everything is consciousness-only," who knows that this is so? If the cognizer too is a manifestation of consciousness, what further consciousness knows that consciousness? An infinite regress follows. Second, Buddhist consciousness arises and ceases momentarily. If each moment of consciousness is independent, the unity of experience—memory, identity, and causal continuity—loses its basis unless a permanent cognizer is accepted as running through it. That permanent cognizer is precisely Brahman or Ātman in Brahmanical thought. Śaṃkara holds that Yogācāra's own reasoning leads toward Brahman–self theory, though it refuses to take the final step.

Against Madhyamaka: Śaṃkara calls it "nihilism" (śūnya-vāda) and subjects it to his harshest criticism. His central objection asks: if everything is empty, what is "emptiness" itself? If it is real, something—emptiness itself—really exists, and Madhyamaka contradicts itself. If emptiness too is empty, Madhyamaka's argument has no reliable epistemological footing and becomes complete nihilism, or annihilationism. More fundamentally, if everything is empty, cognition and liberation are empty too. The pursuit of liberation then loses its meaning, and Madhyamaka cannot provide a positive theory of liberation.³

A figure of historical success, not the legendary hero of debate

Traditional narratives draw chiefly on later Vedānta biographies, the various Śaṃkara-vijaya works. Among the best known is the Śaṅkaradigvijaya attributed to Mādhava, whose received text Lorenzen places in the seventeenth to eighteenth centuries. They portray Śaṃkara as a legendary figure who traveled throughout India and defeated Buddhist thinkers one after another without exception, the hero who drove Buddhism out of India. This image requires substantial revision.

Historians have identified several problems.⁴ First, records of Śaṃkara's debating victories come almost entirely from Vedānta's own biographies, mostly written centuries after his death. No contemporary Buddhist text records a debate with him. Second, his school did not achieve immediate supremacy through his work. Even in the fourteenth century, Advaita still had to contend with dualism and qualified nondualism; the narrative that made it the essence and culmination of Indian philosophy took shape only in the nineteenth century. Buddhism had already largely disappeared from India by the fourteenth century. Third, South Indian Buddhism was declining in the seventh and eighth centuries, before Śaṃkara's active period. What he supposedly "defeated" was an already gravely weakened tradition.

This book's position is that Śaṃkara was a philosopher of some ability. His critiques of the Buddhist schools were serious philosophical work, not merely debating rhetoric. His nondual system prevailed under particular historical conditions and became the main axis of later orthodox Indian philosophy. But the story that "he destroyed Buddhism" is a victor's retrospective construction. After Hindu philosophy prevailed in a competition lasting centuries, its tradition needed a single emblematic figure to whom victory could be attributed. The factors that ended Indian Buddhism included institutional detachment from society, loss of royal patronage, the blurring of identity through Tantra, and the final military assaults. Victory or defeat in debate was not decisive. Tradition even gave Śaṃkara the ironic epithet "crypto-Buddhist" (pracchannabuddha), meaning that his nondualism so closely resembled Buddhism that it was Buddhism in Hindu guise. The label shows, from another angle, that the philosophical boundary was far less sharp than the legendary struggle to the death suggests.

Assessing the force of Śaṃkara's criticisms, and a modern fallacy

Serious philosophical work does not necessarily mean philosophical depth. Close examination of these criticisms reveals problems.

The objection to Madhyamaka—"if everything is empty, emptiness itself really exists, so Madhyamaka contradicts itself"—is a classic misreading of Nāgārjuna. In the Vigrahavyāvartanī, Nāgārjuna already answered explicitly that emptiness itself is empty. He never asserted "emptiness" as a separately established real substrate. It describes the dependent arising and lack of intrinsic nature of all dharmas, rather than asserting the annihilationist claim that "nothing exists." In branding Madhyamaka nihilistic, Śaṃkara attacks a straw man. This judgment must be restricted to this particular argument. After examining Śaṃkara's arguments against Buddhism as a whole, Ingalls still judged them "not pointless but deeply significant and worthy of study." To say that Śaṃkara attacks a straw man on emptiness is not to dismiss all his arguments.³

The critique of Yogācāra—"who knows consciousness-only?"—has some force, but fails to answer a response the school had already given. Dignāga and Dharmakīrti's theory of self-cognition (svasaṃvedana) holds that consciousness reflexively knows itself while knowing its object and needs no external, permanent observer. Śaṃkara's argument is in fact circular. He needs a permanent self, Brahman or Ātman, as the ground of cognition, but the existence of that self is precisely what is disputed and cannot be presupposed.

Advaita's central premise is that Brahman is self-established pure consciousness, with the world superimposed upon it. This is more an assertion than an argument. Asking how Brahman's intrinsic nature is established brings the Madhyamaka question into view: anything established by intrinsic nature arises dependently. If Brahman is not dependent on conditions, how can it interact with the world? If it is dependent, it is not the absolute reality Śaṃkara describes. This question has remained contested within Vedānta through successive generations; it is not settled.

This leads to a modern view that needs direct refutation. Some writers infer the philosophical conclusion that "Buddhist no-self (anātman) is untenable" from the historical outcome that "Śaṃkara won the debates and Vedānta replaced Buddhism." This is untenable on both historical and philosophical grounds.

Historically, the evidence that Śaṃkara actually "won the debates" is extremely weak. Indian Buddhism's disappearance resulted from institutional, social, military, and other causes, with almost no direct causal connection to the outcome of philosophical debates, as this chapter has argued at length.

Philosophically, a proposition's truth is not decided by which school survives in history. Śaṃkara's criticisms of no-self rest on a misreading of Madhyamaka and neglect of Yogācāra's reply. Their actual philosophical force falls far short of establishing that no-self is untenable. The question of no-self also remains open in contemporary philosophy. Parfit's reductionism about personal identity (3.5), Thomas Metzinger's no-self neurophenomenology, and Evan Thompson's synthesis of Buddhism and consciousness science all treat no-self as a serious philosophical proposition. Ending this debate by saying "Śaṃkara won" misunderstands both the history of philosophy and contemporary philosophy.

V. External Factor One: The Hindu Revival¶

The organization of Brahmanical traditions

From the fifth century, during the Gupta period, Brahmanical traditions underwent large-scale organization and revival. Gupta kings strongly supported Brahmin priests, revitalized Vedic traditions, and established temples throughout their territories. This did not contradict their Buddhist patronage—ancient Indian kings generally supported several traditions at once—but the emphasis had shifted.

The rise of the bhakti movement

From about the seventh century, religious movements centered on emotional personal devotion—bhakti, loving devotion—arose first in Tamil regions, spread across South India, and gradually moved north. Tamil Śaiva poets, the Nāyaṉmār, and Vaiṣṇava poets, the Āḻvār, composed many emotionally powerful hymns in local languages, enabling ordinary people to participate in religious life directly and fervently.

This form of religion contrasted sharply with Buddhism's monastic scholarly tradition. Bhakti songs could be sung in everyday village life. People could sing them without entering a monastery, learning to read, or understanding complex philosophy. Only sincere love for a deity was required. Buddhism in the age of the great monasteries lacked this accessibility.⁴

VI. External Factor Two: The Loss of Royal Patronage¶

Loss of royal patronage runs through the whole history of Indian Buddhist decline. Its causes were not simply kings "converting" to Hinduism; changes in political structure mattered more:

Localization and fragmentation: from about the eighth century, the Indian subcontinent was highly fragmented politically, with small kingdoms continually rising and falling. Their limited finances made large institutions such as Nālandā difficult to sustain. To gain support among local Brahmin elites and ordinary people, their kings also tended to favor local temple traditions over distant great monasteries.

Competition for patronage: Jainism and the various Hindu schools also actively sought royal support. In an environment of religious competition, Buddhism was not maliciously singled out; it gradually lost ground in the contest for patronage.

VII. External Factor Three: The Final Blow of Islamic Invasion¶

The entry of Islamic powers into South Asia, from Muḥammad bin Qāsim's conquest of Sindh in 711 to the establishment of the Delhi Sultanate in the late twelfth century, spanned about five hundred years. The devastating blows to Indian Buddhism, however, were concentrated in Bakhtiyar Khilji's campaigns in Bihar and Bengal from 1193 to 1203, described in detail in 8.5.

Why the blow was so devastating

First, the great monasteries were highly concentrated physical targets. Buildings, monks, and texts were gathered together and easily destroyed. Hindu temples were dispersed across the country, while Buddhism had concentrated almost its entire institutional presence in a few great monasteries.

Second, oral transmissions were severed. Many Buddhist practice traditions, especially esoteric lineages, required living gurus to sustain them. The killing of large numbers of monks destroyed living traditions that could not be fully recorded in writing. This loss was irreversible.

Third, Brahmins had a different local foundation. They received grants of villages and land, and could perform most of their rites independently, without bringing in a monastic community from elsewhere. Buddhist monasteries depended on networks of support and mobile groups of monks. Material evidence supports this asymmetry. Whether a destroyed monastery could be rebuilt locally, however, is an inference this book draws from it, without direct historical documentation.⁵

Historians' debates

The emphasis on "Islamic invasion as the principal cause" sometimes has a distinctly political historical coloring. Modern Indian narratives of religious nationalism often blame Buddhism's disappearance directly on Islamic invasion. This conveniently ignores the fact that South Indian Buddhism had disappeared centuries before Islamic forces arrived.

VIII. Why Buddhism Survived Elsewhere¶

In contrast to its disappearance in India, Buddhism has continued to flourish in East Asia, Southeast Asia, and Tibet to this day. The comparison provides indirect corroboration of the causes of its decline in India.

Sri Lanka: the Vibhajyavāda school established a strong lay base there, while geographical isolation also prevented direct attacks by Islamic military forces.

Southeast Asia: supported by local royalty and rooted in local society, Buddhism developed a strong Southern, or Theravāda, tradition entirely independent of India's great monasteries. When Buddhism disappeared in India, Southeast Asian Buddhism was already self-sustaining.

Tibet: the systematic transplantation of Indian Buddhism took place precisely during the richest period of its scholarly tradition, the eighth to twelfth centuries. Tibet's geographical isolation kept Islamic armies out. Tibetan systematic translation and preservation of Indian Buddhist texts also meant that this intellectual heritage survived relatively intact in Tibet after disappearing in India. In a sense, Tibet became Indian Buddhism's most complete "repository."

East Asia: local traditions independent of India had already formed from around the sixth century. By the time Indian Buddhism disappeared, East Asian Buddhism was fully established in its own societies.

IX. Historiographical Debate and This Book's Overall Judgment¶

This book holds that Indian Buddhism's decline and disappearance resulted from multiple factors accumulating and interacting over centuries, without a single principal cause:

The Hindu revival, Brahmanism's renewed appeal to intellectual elites, may have been the deepest cause. Buddhism's detachment from India's social structure was its most persistent weakness, and Islamic invasion the most direct agent of its end. Equating the final blow with the fundamental cause is a historical error, one that political agendas have exploited.

If Indian Buddhism in the early twelfth century had retained the broad popular roots, strong lay networks, and dispersed system of transmission of its early period, a few military assaults alone could not have eradicated it. Hinduism and Jainism survived the same Islamic conquests, demonstrating the point.

X. Aftermath: Survival and Revival¶

Scattered survival

Buddhism in India did not entirely vanish after the thirteenth century; it became extremely marginal. In Nepal's Kathmandu Valley, the Newars preserved a distinctive lay Buddhist tradition that survives to this day. Small numbers of Buddhist believers and Buddhist sites also survived in parts of South India.

The late nineteenth-century revival

Anagarika Dharmapala (1864–1933) promoted the restoration of Buddhist sacred places such as Bodh Gaya and established the Mahā Bodhi Society in India, renewing Indian intellectuals' interest in their country's Buddhist history.

The Ambedkar movement

The most historically consequential event in twentieth-century Indian Buddhism was Bhimrao Ramji Ambedkar's mass conversion in 1956. Ambedkar (B. R. Ambedkar, 1891–1956) led about 500,000 Dalits, the low-caste or casteless groups called "untouchables," into Buddhism. His reason was that Buddhism's teachings of no-self and rejection of caste were the strongest philosophical resources against the caste system. This "Neo-Buddhist Movement" raised India's Buddhist population from almost zero to millions, with continued growth.

This modern revival is not a direct continuation of the ancient tradition. It is an entirely new social movement, drawing on Buddhism as a spiritual resource against social inequality. The topic deserves separate discussion (see Essay 12).

References¶