Buddhist Metaphysics

A Simplifying Introduction

Buddhist metaphysics is not one doctrine but a 2,500-year argument — and its organising question is: what exists, and in what sense? From three observations about experience — everything changes (impermanence), nothing stands alone (dependent arising), persons are not simple, lasting selves (not-self) — its schools built sharply divergent ontologies: a pluralist realism of momentary constituents; a radical “emptiness” that dissolves intrinsic nature altogether; a “mind-only” idealism; and East Asian systems in which each thing contains all things. The recurring shape of the debate is the same everywhere: each position is pressed as a middle way between reification (things with fixed, independent natures) and nihilism (nothing at all). Much of Buddhist philosophy can be read as a sustained attack on substance-based metaphysics: substances would need ontological separation, internal unity, and sameness over time — and Buddhists deny all three. ^{1 2}

The shared core: impermanence, dependence, not-self

The common heritage of all schools is a process ontology. Conditioned phenomena arise and cease “subject to numerous causes and conditions”; the world is not made of substances with changing qualities, but of events in constant conditioned construction (dependent arising, pratītyasamutpāda). The not-self doctrine (anātman) applies this to persons: human beings are “reducible to the physical and psychological constituents and processes which comprise them” — the five aggregates (skandhas). The person is neither identical to the aggregates nor something separate from them, but a dependent designation: as a chariot is to its parts, so “person” is to the aggregates. ^{3 1 4}

The two truths

Already in the early tradition, discourse was split into conventional truth (saṃvṛti-satya) and ultimate truth (paramārtha-satya). The distinction began as an exegetical device for reconciling apparently inconsistent teachings, and became the axis of Buddhist ontology: each school is, in effect, named by the theory of the two truths it upholds. There is no single theory of the two truths in Indian Buddhism — the schools agree on the vocabulary but disagree on what falls on which side, and on how the two relate. ²

Abhidharma realism: dharmas and momentariness

The Abhidharma (“higher teaching”) project analysed conscious experience — “one’s ‘world’” — into its constituent mental and physical events, dharmas, as the theoretical counterpart to meditation. It produced intersecting taxonomies: the Theravāda’s 82 dhamma categories (consciousness, mental factors, materiality, and the one unconditioned item, nirvāṇa) and the Sarvāstivāda’s 75 dharmas in five categories. Dharmas were initially individuated by their svabhāva (intrinsic nature) as a categorial criterion — what a dharma is — but mature Abhidharma drew ontological conclusions from this: dharmas came to be seen as the real entities (dravya), and “to be determined by intrinsic nature” entailed existence. ⁵

Two consequences shaped everything after. Momentariness: the schools radicalised impermanence into the doctrine that phenomena last only a moment (kṣaṇa; estimates of 0.13–13 ms), with material reality reduced to momentary atoms and mental reality to discrete consciousness moments; Vasubandhu’s distinctive argument holds that things must self-destruct, because destruction cannot be caused (its ostensible object is a non-existent and cannot be a result), and change is impossible for something with a single nature. The dispute over what exists: the Sarvāstivādins (“advocates of the doctrine that all things exist”) held that dharmas — past, present, and future — exist as real entities in any given moment; the Theravāda rejected this, holding that dhammas exist only in the present. Against both, the Sautrāntika strand tied ultimate reality to unique particulars (svalakṣaṇa) and much else to conceptual construction. ^{5 4}

Madhyamaka: emptiness and the end of intrinsic nature

Nāgārjuna (c. 150–250 CE) turned the Abhidharma’s key term against its system: if svabhāva means being “part of the basic furniture of the world”, independent of everything else — the end-point of the chain of dependence relations — then there is no such thing. All phenomena are empty (śūnyatā) of intrinsic nature, and emptiness is itself empty: “there is no thing that is not dependently arisen; therefore, there is no such thing that is not empty” (MMK 24.19). This is presented as the middle way: to be empty is not to be nothing, but to be causally conditioned; wherever emptiness applies, causal efficacy applies, and vice versa. ^{6 2}

Nāgārjuna’s method is regress and reductio: four-cornered (catuskoti) refutations exhaust the ways cause and effect could relate (same / different / both / neither) and find each presupposing svabhāva; the same pattern is applied to change, the self, knowledge (the epistemic instruments neither establish themselves nor each other), and language. The conclusion is not that causation is impossible but that our understanding of it rests on a faulty premise — the presupposition of intrinsic nature. Later Madhyamaka split over method and ontology: Svātantrika (Bhāvaviveka, then Jñānagarbha; Śāntarakṣita and Kamalaśīla) granted things conventional intrinsic reality so that they could be causally efficient, and allowed Madhyamikas their own positive arguments; Prāsaṅgika (Buddhapālita, vindicated by Candrakīrti) rejected everything intrinsic, even conventionally — “emptiness is always empty” — and confined itself to reductio. Candrakīrti’s line became, centuries later, the official philosophy of Tibetan Buddhism. ^{2 7 6}

Yogācāra: appearance-only and the three natures

The other great Mahāyāna school, Yogācāra, begins with the mind: what we are directly aware of is always a mental representation, and the causal story behind experience — subliminal impressions (vāsanās) ripening from the storehouse consciousness (ālayavijñāna) — is itself mental. Hence “appearance-only” (vijñaptimātra): external objects are not even conventionally real; the whole universe is, in this analysis, a mental universe. ^{2 8}

The three natures (trisvabhāva) — elaborated by vasubandhu — map the structure: the fabricated nature is “how things appear” (in particular, as independent subjects and objects); the dependent nature is the causal process by which experiences arise; the perfected nature is the absence of the fabricated in the dependent — suchness (tathatā). The three are “one reality viewed from three angles”. Interpretations of the school’s idealism range from ontological (nothing beyond mind) to epistemological (mind-priority without denying a beyond), and scholars stress its “peculiarly Buddhist” character: consciousness here is not a mental substance — not Berkeley’s souls nor Hegel’s spirit — and the ultimate, for Vasubandhu, is an ineffable thusness known only to buddhas. The three-natures framework also reveals a deep agreement between Abhidharma and Yogācāra — both are ontologically foundationalist (dharmas for one, consciousness for the other) — which sets both against Madhyamaka’s anti-foundationalism. ^{8 4}

The logico-epistemological school: Dignāga and Dharmakīrti

A distinct Buddhist tradition — the pramāṇa (“valid knowledge”) school of Dignāga and Dharmakīrti — built a sparse, thoroughly nominalist ontology: only unique particulars (svalakṣaṇa) are real, and the criterion of reality is causal power (arthakriyā): “whatever has causal powers, that really exists; anything else is merely customarily existent”. Universals — blueness, fingerhood, enduring substances — are unreal fictions needed for thought and language, attacked through the “one-many” problem. This makes everything momentary (only series of qualitatively similar moments give the illusion of persistence), and gives language its Buddhist theory of meaning, apoha: a word refers not by picking out a shared universal but by excluding what it is not. This school “provoked the most sophisticated and most important philosophical debates with non-Buddhist rivals”, including on universals and causal theories of properties. ⁹

Buddha-nature and the East Asian schools

Chinese Buddhism received the Indian schools “piecemeal” and eclecticised them, treating doctrines as partial views to be ranked in hierarchic schemes of panjiao (doctrinal classification) — a practice that licensed innovation. Huayan (the “Flower Garland” school, with Fazang and Zongmi its great systematizers) inherited Madhyamaka conditioning and Yogācāra vocabulary, but pushed interdependence further: because a thing’s identity depends on others, “one is all, and all is one” — the rafter is the building, and the building is the rafter; the whole cosmos is depicted as Indra’s net, each jewel reflecting every other. Samsara and nirvana are not two worlds but one reality rightly and wrongly seen (Fazang’s golden lion). Ziporyn calls this “omnicentric holism”. Tiantai went further through its three truths — emptiness, provisional positing, and “the center” — a thoroughgoing contextualism in which every entity’s identity derives entirely from its relations, “intersubsumptive” with all others: every moment of experience is the whole of reality manifesting in one form, and the whole is present in each part (“three thousand realms in a single thought”). In Chan/Zen the practical upshot became sudden insight into one’s already-present buddha-nature (tathāgatagarbha — the theme of the Awakening of Faith, which locates reality in a “One Mind” whose aspects, suchness and samsara, are mutually inclusive). The result was a family of distinctively Chinese, thoroughly immanentist ontologies: no transcendent elsewhere, no ultimate outside the changing world. ^{10 11 1}

Tibetan systematisation

In Tibet all schools — Nyingma, Kagyü, Sakya, Gelug — took themselves to be followers of Candrakīrti’s Prāsaṅgika, and then fought over what that meant. Central questions: does the Prāsaṅgika hold any position at all; what is the basis of the division of the two truths; are they distinct or identical? Gelug (Tsongkhapa) reads the two truths as two natures of every single entity — its deceptive conventional nature and its ultimate nature — so that “a table and its emptiness are a single entity” known under different perspectives; knowledge of one truth therefore suffices for knowledge of the other, and both stand on an equal footing. The non-Gelug schools (Nyingma, Kagyü, Sakya) reject the dual-nature theory and make the division purely perspectival: conventional truth is reality as experienced by deluded ordinary minds, ultimate truth as known in the meditative equipoise of exalted beings — incommensurable, such that no ordinary being can know the ultimate and no fully awakened buddha experiences the conventional. ¹²

Contemporary reception

Madhyamaka is now an active participant in Western metaphysics: its rejection of foundation and intrinsic nature engages the contemporary grounding debate; its position is “opposed to the brand of realism currently found in much of contemporary analytic philosophy”; formal models of foundationless ontologies have been built (Priest). Whether Madhyamaka is essentially a religious doctrine or a free-standing philosophical system is itself debated. Its parts-and-wholes analyses — persons as organisations of aggregates, wholes as dependent designations — sit in the same problem space as the modern reduction/emergence question (see emergence), and its regress arguments mirror the classic Western regress problem (see agrippas-trilemma). ⁶

See Also

• nagarjuna — founder of Madhyamaka; emptiness, the catuskoti, anti-foundationalism
• vasubandhu — Abhidharma systematiser and Yogācāra founder; three natures, momentariness, appearance-only
• agrippas-trilemma — the Western regress problem; Madhyamaka’s arguments as an anti-foundationalist response
• emergence — dependence without reduction; parts/wholes; the person as organised whole
• possibilism-actualism — the scope and modes of existence; Sarvāstivāda’s “all exists” as an ancient ontological dispute
• ontological-arguments — a priori reasoning to a necessary being, contrasted with Madhyamaka’s dissolution of necessary natures
• modal-logic — classical necessity/possibility apparatus; non-classical treatments of the catuskoti

References

• Ronkin, N. (2026). “Abhidharma.” Stanford Encyclopedia of Philosophy (substantive revision 31 Mar 2026). ⁵
• Thakchoe, S. (2022). “The Theory of Two Truths in India.” Stanford Encyclopedia of Philosophy (substantive revision 16 May 2022). ²
• Gold, J. C. (2021). “Vasubandhu.” Stanford Encyclopedia of Philosophy (substantive revision 7 Jan 2021). ⁴
• Westerhoff, J. C. (2026). “Nāgārjuna.” Stanford Encyclopedia of Philosophy (substantive revision 31 May 2026). ⁶
• Hayes, R. (2023). “Madhyamaka.” Stanford Encyclopedia of Philosophy (substantive revision 18 Aug 2023). ⁷
• Szanyi, S. (2024). “Yogācāra.” Stanford Encyclopedia of Philosophy (first published 7 Jul 2024). ⁸
• Tillemans, T. (2026). “Dharmakīrti.” Stanford Encyclopedia of Philosophy (substantive revision 7 Apr 2026). ⁹
• Thakchoe, S. (2022). “The Theory of Two Truths in Tibet.” Stanford Encyclopedia of Philosophy (substantive revision 28 May 2022). ¹²
• Coseru, C. (2012). “Mind in Indian Buddhist Philosophy.” Stanford Encyclopedia of Philosophy (substantive revision 12 Oct 2012). ³
• Ziporyn, B. (2022). “Tiantai Buddhism.” Stanford Encyclopedia of Philosophy (substantive revision 13 Nov 2022). ¹¹
• Van Norden, B. & Jones, N. (2024). “Huayan Buddhism.” Stanford Encyclopedia of Philosophy (substantive revision 17 Sep 2024). ¹⁰
• Perkins, F. (2023). “Metaphysics in Chinese Philosophy.” Stanford Encyclopedia of Philosophy (substantive revision 16 Oct 2023). ¹

Footnotes

1. raw/articles/sep-chinese-metaphysics.md ↩ ↩² ↩³ ↩⁴

2. raw/articles/sep-two-truths-india.md ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

3. raw/articles/sep-mind-indian-buddhism.md ↩ ↩²

4. raw/articles/sep-vasubandhu.md ↩ ↩² ↩³ ↩⁴

5. raw/articles/sep-abhidharma.md ↩ ↩² ↩³

6. raw/articles/sep-nagarjuna.md ↩ ↩² ↩³ ↩⁴

7. raw/articles/sep-madhyamaka.md ↩ ↩²

8. raw/articles/sep-yogacara.md ↩ ↩² ↩³

9. raw/articles/sep-dharmakirti.md ↩ ↩²

10. raw/articles/sep-huayan-buddhism.md ↩ ↩²

11. raw/articles/sep-tiantai-buddhism.md ↩ ↩²

12. raw/articles/sep-two-truths-tibet.md ↩ ↩²