Indian Philosophy: The Six Schools, the Darśanas and the Great Debates

Indian philosophy is the family of philosophical traditions that grew up in the Indian subcontinent, from the Upaniṣads and the early Buddhists onwards. Its classical schools, or darśanas, include six “orthodox” schools — Nyāya, Vaiśeṣika, Sāṃkhya, Yoga, Mīmāṃsā and Vedānta — and the Buddhist, Jain and Cārvāka schools, which argued over knowledge, self, logic and liberation.

For two thousand years these schools argued with one another in writing. A classical text states the opponent’s view (pūrvapakṣa) before its own conclusion; the result is a rich body of work on how we know, what a self is, how inference works and what art does to us.

What does darśana mean?

Sanskrit has no exact word for “philosophy”. The closest is darśana, from a root meaning “to see”: a view, a way of seeing how things are. A darśana is a school with a root text, usually a set of terse aphorisms (sūtras), and centuries of commentaries that interpret, defend and revise it.

Many darśanas present themselves as paths to liberation (mokṣa) from rebirth, which led some to call Indian philosophy “spiritual” rather than argumentative. Scholars such as Bimal Krishna Matilal and J. N. Mohanty pushed back: the schools contain rigorous theories of logic, knowledge and language. The aims were often liberation; the method was argument.

Āstika and nāstika: what the classification means

The schools are often sorted into āstika and nāstika, usually translated “orthodox” and “heterodox”. In the sense that became standard, an āstika school accepts the authority of the Vedas, the ancient Sanskrit scriptures; Buddhists, Jains and Cārvākas do not. Three cautions help.

• It is not theist versus atheist. The words come from asti, “there is”, and older uses concerned whether one affirms another world, karma or the Vedas. Classical Sāṃkhya and Mīmāṃsā are āstika yet do not argue for a creator God; Jains and Buddhists deny a creator yet hold detailed views of karma and liberation.
• It is a later map. The schools did not grow up as two teams; the fixed list of “six orthodox systems” became standard only in late medieval surveys and modern textbooks. An eighth-century Jain author, Haribhadra, wrote a survey of “six philosophies” that included Buddhists and Jains.
• It is evaluative. The labels came from those who accepted the Vedas, and nāstika could be an insult. Many scholars prefer “Brahmanical” and “non-Brahmanical”, or simply name the schools.

The six schools of Indian philosophy

The six āstika schools are often taught in three closely related pairs.

School	Traditional root text	Core idea
Nyāya	Nyāya Sūtra, attributed to Gautama (Akṣapāda)	Logic and the means of knowledge; a self, a world and, in later Nyāya, God established by argument
Vaiśeṣika	Vaiśeṣika Sūtra, attributed to Kaṇāda	A catalogue of what exists — substances, qualities, actions, universals, inherence and more — and a world of atoms
Sāṃkhya	Sāṃkhya Kārikā of Īśvarakṛṣṇa	Two kinds of reality: pure consciousness (puruṣa) and matter (prakṛti), woven of three strands (guṇas); effects pre-exist in their causes
Yoga	Yoga Sūtras, attributed to Patañjali	Sāṃkhya’s picture plus a discipline for stilling the mind, in eight limbs, of which posture is only one
Mīmāṃsā	Mīmāṃsā Sūtra, attributed to Jaimini	How to interpret Vedic injunctions; duty (dharma) known from a Veda that has no author
Vedānta	Brahma Sūtra, attributed to Bādarāyaṇa, read with the Upaniṣads and the Bhagavad Gītā	Brahman, the ground of all things, and its relation to the self and the world

The pairs leaned on each other: Nyāya took over Vaiśeṣika’s list of what exists, Yoga took Sāṃkhya’s metaphysics, and Vedānta (“the end of the Veda”) grew out of Mīmāṃsā’s methods of reading scripture. Vedānta later split into rival schools.

Advaita, Viśiṣṭādvaita and Dvaita Vedānta

• Advaita (non-dualism), systematised by Adi Shankara (Śaṅkara): only Brahman, undivided consciousness, is real in the full sense; the self (ātman) is Brahman; the world of many things is appearance (māyā), like a rope mistaken for a snake. Sriharsa later defended it by attacking every rival definition of knowledge.
• Viśiṣṭādvaita (qualified non-dualism), Rāmānuja: Brahman is a personal God, Viṣṇu-Nārāyaṇa; selves and the world are real and form God’s body, distinct from God yet inseparable. Devotion (bhakti) is central.
• Dvaita (dualism), Madhva: five real and eternal differences — between God and selves, God and matter, self and self, self and matter, and matter and matter.

The heterodox schools: Buddhist, Jain, Cārvāka and Ājīvika

From around the fifth century BCE, wandering ascetics (śramaṇas) challenged Vedic ritual and priestly authority. Their schools are as central to Indian philosophy as the six.

• Buddhist. The Buddha taught that there is no permanent self and that everything arises from conditions. Nagarjuna’s Madhyamaka, the Yogācāra of Asaṅga and Vasubandhu, and the logicians Dignāga and Dharmakīrti were among the other schools’ sharpest critics, and were answered in turn. See Buddhist philosophy.
• Jain. Mahavira taught non-injury (ahiṃsā) towards every living being (see the animal ethics card) and the freeing of the soul (jīva) from karmic matter. Jain thinkers developed anekāntavāda, the many-sidedness of reality, and a sevenfold scheme of qualified assertion: “in some respect it is, in some respect it is not…”. See Jainism.
• Cārvāka or Lokāyata (“the worldly”). Materialists: only perception yields knowledge, consciousness arises from the body’s elements, and nothing survives death. Almost all their texts are lost (Jayarāśi’s sceptical treatise is the main exception), so we know them through opponents; Ajita Kesakambali, a contemporary of the Buddha, is the earliest recorded voice. See Carvaka.
• Ājīvika. Associated with Makkhali Gosāla, who taught that everything is fixed by destiny (niyati). Its teachings are known only from Buddhist and Jain reports.

Some fit neither column, such as the grammarian Bhartrhari, for whom the sentence, not the word, is the unit of meaning.

Key debates in Indian philosophy

Indian thinkers appear across The Coordinates, the 131 cards from The Coordinates of Thought, above all in epistemology, logic and aesthetics.

How do we know? The pramāṇas

A pramāṇa is a means of valid knowledge, and every school had to say which it accepted. The sources of knowledge card sets the answers side by side.

School	Means of knowledge accepted
Cārvāka	Perception only; inference needs a universal connection no one perceives
Buddhist (Dignāga, Dharmakīrti) and Vaiśeṣika	Perception and inference
Sāṃkhya and Yoga	Perception, inference and testimony
Nyāya	Perception, inference, comparison and testimony, each irreducible
Mīmāṃsā (Prabhākara)	Five: adds postulation (arthāpatti)
Mīmāṃsā (Kumārila) and Advaita Vedānta	Six: adds non-apprehension, for knowing absences

Is a cognition valid unless something defeats it, as Kumārila Bhaṭṭa held, or must its validity be confirmed, as Nyāya held? Can a true belief fall short of knowledge? The Buddhist Dharmottara described beliefs that are true only by luck more than a thousand years before Edmund Gettier; see the Gettier problem card.

Figure	Dates	Tradition	Contribution
Ajita Kesakambali	contemporary of the Buddha	Indian materialist	An early materialist stance, before the Lokāyata schools, known only through Buddhist and Jain reports
Gautama (Akṣapāda)	trad. c. 2nd c. CE	Indian Nyaya	The four-pramana framework
Dignāga	c. 480–540	Indian Buddhist	Reduced the list to two and defended the reduction
Ibn al-Haytham	c. 965–1040	Islamic	Experiment as a disciplined source
John Locke	1632–1704	European modern	No innate ideas; the mind begins empty
Immanuel Kant	1724–1804	European modern	Thoughts without content are empty, intuitions without concepts are blind (A51/B75)
Dharmakīrti	c. 6th–7th c. CE	Indian Buddhist	Only perception and inference are sources of knowledge, both grounded in causal efficacy
Suhrawardi	1154–1191	Islamic	Knowledge by presence (ʿilm ḥuḍūrī): self-knowledge needs no representation

Is there a self? Ātman and anātman

The Upaniṣads seek the self (ātman). Yājñavalkya calls it the unseen seer, describable only by negation — “not this, not this” — and Uddālaka Āruṇi teaches his son that the self is one with the being from which all things unfold: “you are that”. Nyāya argued that a lasting self is needed to explain desire, effort and memory; Sāṃkhya counts many pure selves; Advaita identifies the self with Brahman. The Buddha denied any permanent self (anātman), and the monk Nagasena compared a person to a chariot: a name for parts, with no further owner among them. The Cārvākas found no self beyond the living body. The personal identity card sets these beside Locke and Parfit.

Logic and debate

Nyāya made inference a formal art. Its standard five-membered example: the hill has fire (thesis), because it has smoke (reason); wherever there is smoke there is fire, as in a kitchen (example); the hill has such smoke (application); so the hill has fire (conclusion). Everything turns on vyāpti, the invariable connection between smoke and fire. From the fourteenth century, Gangesa’s Navya-Nyāya (“new Nyāya”) built a precise technical language for such relations.

Nyāya also distinguished kinds of debate — vāda, aimed at truth; jalpa, aimed at victory; vitaṇḍā, attack without a thesis of one’s own — and catalogued fallacious reasons. Jain logicians qualified every assertion by standpoint, and Nagarjuna’s four-cornered negation now interests logicians who tolerate some contradictions. See Syllogistic logic, Argumentation theory and Paraconsistent logic.

How should one act? Dharma and the Gītā

Classical ethics speaks of four aims of life — duty (dharma), prosperity (artha), pleasure (kāma) and liberation (mokṣa) — and most schools, though not the Cārvākas, accepted karma and rebirth. The Bhagavad Gītā opens with the warrior Arjuna refusing to fight his own kin; Krishna answers that one should do one’s duty without attachment to its fruits, and sets out paths of action, knowledge and devotion. Readers draw opposite lessons: Gandhi found in it selfless action compatible with non-violence, while critics such as B. R. Ambedkar argued that duties fixed by birth upheld caste.

What does art do to us? Rasa

Bharata’s treatise on drama, the Nāṭyaśāstra, holds that rasa, aesthetic “flavour”, arises from combining a play’s causes of emotion, its outward signs and its passing feelings. Later critics disputed what rasa is: an intensified emotion in the character (Bhatta Lollata), an emotion the audience infers, as one infers fire from smoke (Sankuka), or an emotion generalised beyond any personal stake (Bhatta Nayaka). Abhinavagupta’s answer, that the spectator relishes a generalised emotion in a non-ordinary kind of experience, became classic. It is one answer on the aesthetic experience card: why is the sadness of a sad song enjoyable?

Indian philosophers: who’s who and timeline

The Indian thinkers most cited on the cards, linked to their profiles (see also Indian philosophy on the site):

Indian Buddhist philosophers appear under Buddhist philosophy:

Period	What happened	Key figures
c. 1500–500 BCE	Vedic hymns, then the early Upaniṣads	Yājñavalkya, Uddālaka Āruṇi
c. 6th–5th century BCE	The śramaṇa movements challenge Vedic ritual	The Buddha, Mahavira, Ajita Kesakambali, Makkhali Gosāla
c. 200 BCE–500 CE	Root texts of the schools; the Gītā; the Nāṭyaśāstra; Madhyamaka and Yogācāra	Bharata, Nagarjuna, Asaṅga, Vasubandhu, Bhartrhari
c. 500–1000	Buddhist logic; Mīmāṃsā and Advaita; rasa theory	Dignāga, Dharmakīrti, Kumārila Bhaṭṭa, Prabhākara, Adi Shankara, Abhinavagupta
c. 1000–1600	Theistic Vedānta; Navya-Nyāya	Udayana, Rāmānuja, Sriharsa, Madhva, Gangesa, Raghunātha Śiromaṇi
19th century–today	Modern and academic Indian philosophy	Vivekananda, Tagore, Aurobindo, Radhakrishnan, Ambedkar, Matilal, Mohanty

For every tradition side by side, see the philosophy timeline.

Modern Indian philosophy

Modern Indian philosophers wrote in English as well as Indian languages, often in dialogue with European thought.

• Vivekananda presented Vedānta to Western audiences, notably in Chicago in 1893.
• Aurobindo argued that the world is a real self-manifestation of Brahman, not an illusion.
• Rabindranath Tagore held that art springs from a surplus in human beings beyond what life requires.
• Radhakrishnan read Advaita as a philosophy of experience and defended intuition as a source of knowledge.
• B. R. Ambedkar argued that caste must be annihilated, not reformed; see Distributive justice.
• Matilal and Mohanty brought classical logic and epistemology into conversation with analytic philosophy and phenomenology.

How to start studying Indian philosophy

1. Read a map first. Peter Adamson and Jonardon Ganeri’s Classical Indian Philosophy follows the schools in order and suits beginners.
2. Then a short classic. The Bhagavad Gītā is the most accessible; the Upaniṣads come next, starting with the Kaṭha.
3. Follow one debate across schools. The sources of knowledge and personal identity cards show the schools answering the same question.
4. Go deeper with a guide. Matilal’s The Character of Logic in India for logic, A Rasa Reader for aesthetics.
5. Join a conversation. Browse Indian philosophy, read Eastern and Western philosophy, or ask a question.

The liveliest conversations in Indian philosophy on the site:

Where do you stand?

Every question here has serious answers on more than one side. Pick a card, read the rival answers, then say which you find strongest and why. Members ask, reply and take sides; reading is free for everyone.

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