Overview

Indian philosophy (Darshana, literally "seeing" or "vision") represents one of the oldest and most diverse intellectual traditions in the world. Unlike Western philosophy which often treats philosophy as a purely academic discipline, Indian Darshana is deeply connected to moksha (liberation) --- the ultimate goal of human life. Indian philosophical schools are broadly classified into Astika (orthodox --- accepting the authority of the Vedas) and Nastika (heterodox --- rejecting Vedic authority).

For UPSC, Indian philosophy appears in GS-I (Indian Culture), Prelims (factual questions on schools, founders, texts), and Essay (philosophical concepts like dharma, karma, ahimsa).

Classification of Indian Philosophical Schools

Category Schools Defining Feature
Astika (Orthodox) Nyaya, Vaisheshika, Sankhya, Yoga, Purva Mimamsa, Uttara Mimamsa (Vedanta) Accept the authority of the Vedas as a valid source of knowledge
Nastika (Heterodox) Charvaka (Lokayata), Buddhism, Jainism Reject the authority of the Vedas

For Prelims: The term "Nastika" does not mean "atheist" in the modern sense. It specifically refers to schools that reject the Vedas as authoritative. Buddhism and Jainism are Nastika despite having rich spiritual and metaphysical traditions. Sankhya is Astika (accepts the Vedas) despite being technically atheistic (does not accept Ishvara/God as a separate entity).

The Six Orthodox Darshanas (Shad Darshana)

The six orthodox schools are traditionally grouped in three complementary pairs: Nyaya-Vaisheshika, Sankhya-Yoga, and Mimamsa-Vedanta.

Nyaya (Logic and Epistemology)

Aspect Detail
Founder Sage Gautama (Akshapada Gautama)
Key text Nyaya Sutras
Core focus Logic, epistemology (theory of knowledge), and valid reasoning
Pramanas (means of knowledge) Accepts four: Pratyaksha (perception), Anumana (inference), Upamana (comparison/analogy), Shabda (verbal testimony/scripture)
Key contribution Developed a rigorous five-membered syllogism (Pancha-Avayava) for logical proof: (1) Pratijna (proposition), (2) Hetu (reason), (3) Udaharana (example), (4) Upanaya (application), (5) Nigamana (conclusion)
Metaphysics Accepts the existence of God (Ishvara) as the efficient cause of the universe; the universe is composed of eternal atoms
Moksha Liberation through right knowledge (tattva-jnana) --- understanding the 16 categories (padarthas) of the Nyaya system

Vaisheshika (Atomism and Metaphysics)

Aspect Detail
Founder Sage Kanada (Kashyapa)
Key text Vaisheshika Sutras
Core focus Metaphysics, categorisation of reality, and atomic theory
Key concept Propounds Paramanu-vada (atomic theory) --- all material objects are composed of indivisible, eternal atoms (paramanu) of four types: earth (prithvi), water (apas), fire (tejas), and air (vayu)
Categories (Padarthas) Originally six: Dravya (substance), Guna (quality), Karma (action), Samanya (generality), Vishesha (particularity), Samavaya (inherence); later added Abhava (non-existence)
Relation to Nyaya Complementary --- Nyaya provides the logical methodology; Vaisheshika provides the metaphysical framework
Moksha Liberation through knowledge of the six/seven categories of reality

For Mains: Vaisheshika's atomic theory (Paramanu-vada) is remarkably similar to modern atomic theory in its insistence that all matter is composed of indivisible, eternal particles. Kanada proposed that atoms combine in pairs (dvyanuka) and triplets (tryanuka) to form visible matter --- a concept that predated Democritus by several centuries.

Sankhya (Dualism)

Aspect Detail
Founder Sage Kapila
Key text Sankhya Sutras; Sankhya Karika by Ishvarakrishna (most influential systematic text)
Core focus Dualistic metaphysics --- the universe consists of two independent, eternal realities
Two realities Purusha (consciousness/self --- passive, eternal, multiple) and Prakriti (matter/nature --- active, eternal, singular)
Evolution of Prakriti Prakriti consists of three gunas: Sattva (purity/knowledge), Rajas (activity/passion), Tamas (inertia/darkness). When equilibrium is disturbed, evolution (srishti) begins
25 Tattvas Sankhya enumerates 25 principles: 1 Purusha + 24 evolutes of Prakriti (including Mahat/Buddhi, Ahamkara, Manas, 5 Jnanendriyas, 5 Karmendriyas, 5 Tanmatras, 5 Mahabhutas)
Theistic position Does not accept Ishvara (God) as a separate entity; liberation comes from discriminative knowledge (viveka-jnana) between Purusha and Prakriti
Moksha Liberation occurs when Purusha realises its distinction from Prakriti

Yoga (Discipline and Practice)

Aspect Detail
Founder Sage Patanjali
Key text Yoga Sutras (196 sutras in 4 chapters/padas)
Core focus Practical discipline for achieving liberation; closely allied with Sankhya's metaphysics
Definition of Yoga "Yogas chitta vritti nirodhah" --- Yoga is the cessation of fluctuations of the mind (Sutra 1.2)
Ashtanga Yoga Eight-limbed path: (1) Yama (restraints), (2) Niyama (observances), (3) Asana (postures), (4) Pranayama (breath control), (5) Pratyahara (withdrawal of senses), (6) Dharana (concentration), (7) Dhyana (meditation), (8) Samadhi (absorption)
Difference from Sankhya Accepts Ishvara (God) as a special Purusha, untouched by afflictions; Sankhya is non-theistic
UNESCO recognition International Day of Yoga (21 June) declared by UN General Assembly in 2014; Yoga inscribed on UNESCO's Intangible Cultural Heritage list (2016)

For Prelims: Patanjali's Yoga Sutras define yoga as "chitta vritti nirodhah" (cessation of mental fluctuations). The Ashtanga Yoga (8-limbed path) sequence is: Yama, Niyama, Asana, Pranayama, Pratyahara, Dharana, Dhyana, Samadhi. The UN International Day of Yoga is 21 June (first observed 2015).

Purva Mimamsa (Ritualism)

Aspect Detail
Founder Sage Jaimini
Key text Mimamsa Sutras (also called Purva Mimamsa Sutras); largest of all sutra works with ~2,500 sutras
Core focus Interpretation of the Vedic rituals (karma-kanda); inquiry into the nature of dharma
Key principle The Vedas are eternal (apaurusheya --- not authored by any person, including God) and self-valid; dharma is what the Vedas command
Epistemology Accepts six pramanas: Pratyaksha, Anumana, Upamana, Shabda, Arthapatti (presumption), and Anupalabdhi (non-apprehension)
Emphasis Proper performance of Vedic rituals (yajnas) leads to desired results (heaven, prosperity); this is the path to dharma
Key scholars Kumarila Bhatta and Prabhakara developed the two main sub-schools
Moksha Early Mimamsa focused on svarga (heaven) through ritual; later incorporated moksha

Uttara Mimamsa / Vedanta (Knowledge of Brahman)

Vedanta is the most influential of the six Darshanas and has three major sub-schools:

Sub-school Founder / Key Proponent Key Text Core Doctrine
Advaita Vedanta (Non-dualism) Adi Shankaracharya (8th century CE) Commentaries on Brahma Sutras, Upanishads, Bhagavad Gita (Prasthanatrayi) Brahman alone is real; the world is maya (illusion); individual self (Atman) is identical with Brahman; "Tat Tvam Asi" (Thou Art That)
Vishishtadvaita (Qualified Non-dualism) Ramanujacharya (11th--12th century CE) Sri Bhashya (commentary on Brahma Sutras) Brahman is real AND the world is real; individual souls and matter are attributes (visheshana) of Brahman; God is Vishnu/Narayana; path of devotion (bhakti)
Dvaita (Dualism) Madhvacharya (13th century CE) Commentaries on Brahma Sutras Brahman (Vishnu), individual souls (jiva), and matter (jada) are three eternally distinct realities; five-fold difference (pancha-bheda)
Concept Advaita Vishishtadvaita Dvaita
Brahman Nirguna (without qualities) Saguna (with qualities); Vishnu/Narayana Saguna; Vishnu is supreme
World Maya (illusion) Real; body of Brahman Real; eternally distinct from Brahman
Atman-Brahman Identical Atman is part of Brahman (body-soul analogy) Eternally distinct
Path to Moksha Jnana (knowledge) Bhakti (devotion) + Prapatti (surrender) Bhakti (devotion)

For Mains: The three schools of Vedanta represent a philosophical spectrum from monism (Advaita) to dualism (Dvaita). Shankara's Advaita influenced the unity of Indian thought; Ramanuja's Vishishtadvaita provided philosophical grounding for the Bhakti movement; Madhva's Dvaita influenced Vaishnavism in Karnataka and the Haridasa tradition. All three engage with the Prasthanatrayi (triple canon): Upanishads, Brahma Sutras, and Bhagavad Gita.

The Three Heterodox Schools (Nastika)

Charvaka / Lokayata (Materialism)

Aspect Detail
Attributed founder Brihaspati (legendary)
Core doctrine Radical materialism; only matter is real; consciousness is a by-product of material elements
Epistemology Accepts only Pratyaksha (direct perception) as a valid means of knowledge; rejects inference, scriptural testimony
Metaphysics Denies the existence of God, soul (atman), afterlife, karma, and moksha
Ethics Pursuit of pleasure (kama) and wealth (artha) is the goal of life; "As long as you live, live happily; eat ghee even if you have to borrow"
Significance Earliest known materialist philosophy in the world; important as a counter-tradition that stimulated philosophical debate

Buddhist Philosophy

Concept Detail
Founder Siddhartha Gautama (the Buddha), 6th--5th century BCE
Four Noble Truths (1) Dukkha --- life is suffering; (2) Samudaya --- suffering arises from desire (tanha/trishna); (3) Nirodha --- suffering can be ended; (4) Magga --- the path to ending suffering is the Eightfold Path
Noble Eightfold Path Right View, Right Intention, Right Speech, Right Action, Right Livelihood, Right Effort, Right Mindfulness, Right Concentration
Pratityasamutpada Dependent Origination --- all phenomena arise in dependence on causes and conditions; nothing has independent, permanent existence
Anatman (Anatta) No-self doctrine --- rejects the Hindu concept of a permanent, unchanging soul (atman)
Three Marks of Existence Anicca (impermanence), Dukkha (suffering), Anatta (no-self)
Major schools Theravada (Southeast Asia), Mahayana (East Asia), Vajrayana (Tibet, Mongolia)
Philosophical sub-schools Sautrantika, Vaibhashika (Abhidharma tradition), Madhyamaka (Nagarjuna --- Shunyavada/emptiness), Yogachara (Asanga, Vasubandhu --- consciousness-only)

Jain Philosophy

Concept Detail
Key proponents Mahavira (24th Tirthankara, 6th century BCE); Umasvati (Tattvarthasutra)
Anekantavada Doctrine of many-sidedness --- reality has multiple aspects; no single viewpoint can capture the whole truth
Syadvada Doctrine of conditional predication --- seven-fold logical framework (Saptabhangi); every statement is conditionally true ("syat" = "in some respect")
Ahimsa Non-violence as the supreme ethical principle; extends to all living beings including microorganisms
Jiva and Ajiva Reality consists of Jiva (soul/consciousness) and Ajiva (non-soul: matter/pudgala, space, time, motion, rest)
Karma theory Karma is conceived as subtle matter (karma-pudgala) that binds to the soul; liberation requires shedding all karma through austerity and right conduct
Moksha Liberation through the Three Jewels (Triratna): Right Faith (Samyak Darshana), Right Knowledge (Samyak Jnana), Right Conduct (Samyak Charitra)

Key Philosophical Concepts Across Schools

Concept Meaning Schools that Accept
Dharma Cosmic order, moral law, duty All schools except Charvaka
Karma Law of moral causation; actions determine future outcomes All except Charvaka
Moksha / Nirvana Liberation from the cycle of birth and death (samsara) All except Charvaka
Atman Individual self/soul Hindu schools (except Charvaka); Jainism (as jiva); Buddhism rejects (anatman)
Brahman Ultimate reality / cosmic principle Vedanta (primary focus); acknowledged in most Hindu schools
Ahimsa Non-violence Central to Jainism and Buddhism; important in Hindu ethics (Yoga, Vedanta)
Samsara Cycle of birth, death, and rebirth All except Charvaka
Maya Illusion / phenomenal world Central to Advaita Vedanta; not accepted by Dvaita or Vishishtadvaita
Prakriti Primordial matter/nature Sankhya, Yoga (fundamental concept)
Purusha Pure consciousness/self Sankhya, Yoga

Indian Logic (Nyaya) --- The Syllogism

The Nyaya five-membered syllogism is a distinctive Indian contribution to formal logic:

Step Sanskrit Name Example
1. Proposition Pratijna "The hill has fire"
2. Reason Hetu "Because it has smoke"
3. Example Udaharana "Wherever there is smoke, there is fire, as in a kitchen"
4. Application Upanaya "The hill has smoke"
5. Conclusion Nigamana "Therefore, the hill has fire"

For Mains: The Indian syllogism differs from the Aristotelian syllogism in two important ways: (1) it has five members instead of three, adding the example and application steps; (2) it moves from particular observation to general principle and back to particular conclusion, making it both inductive and deductive. Dignaga (Buddhist logician) later refined Indian logic by reducing it to a three-membered syllogism.

Indian Knowledge Systems Beyond Philosophy

Knowledge System Sanskrit Term Description
Ayurveda Science of Life Ancient medical system; Charaka Samhita (internal medicine), Sushruta Samhita (surgery); based on three doshas: Vata, Pitta, Kapha
Jyotisha Astronomy/Astrology One of the six Vedangas; includes mathematical astronomy; Aryabhata's Aryabhatiya, Varahamihira's Brihat Samhita
Ganita Mathematics Indian contributions: zero (shunya), decimal place-value system, algebra (Brahmagupta), trigonometry (Aryabhata), infinite series (Kerala school)
Vyakarana Grammar Panini's Ashtadhyayi --- earliest formal grammar in any language; 3,959 rules; influenced modern linguistics
Arthashastra Political Science Kautilya's treatise on statecraft, governance, economics, and military strategy
Natyashastra Performing Arts Bharata Muni's encyclopedic work on drama, dance, music; Rasa theory (nine rasas)

Comparative Table: Orthodox vs. Heterodox Schools

Feature Nyaya Vaisheshika Sankhya Yoga Mimamsa Vedanta Charvaka Buddhism Jainism
Vedic authority Yes Yes Yes Yes Yes Yes No No No
God (Ishvara) Yes Yes No Yes Early: No; Later: Yes Varies by sub-school No No (original) No
Atman Yes Yes Yes (Purusha) Yes (Purusha) Yes Yes No No (Anatman) Yes (Jiva)
Karma Yes Yes Yes Yes Yes Yes No Yes Yes (as matter)
Focus Logic Atomism Dualism Practice Ritual Knowledge Materialism Middle Path Asceticism

Epistemology --- Pramanas Across Schools

The number of valid means of knowledge (pramanas) accepted by each school is a frequently tested Prelims topic:

School No. of Pramanas Pramanas Accepted
Charvaka 1 Pratyaksha (perception) only
Buddhism (Vaibhashika) 2 Pratyaksha, Anumana (inference)
Vaisheshika 2 Pratyaksha, Anumana
Sankhya 3 Pratyaksha, Anumana, Shabda (testimony)
Yoga 3 Pratyaksha, Anumana, Shabda
Nyaya 4 Pratyaksha, Anumana, Upamana (comparison), Shabda
Mimamsa 6 Pratyaksha, Anumana, Upamana, Shabda, Arthapatti (presumption), Anupalabdhi (non-apprehension)
Advaita Vedanta 6 Same as Mimamsa

For Prelims: Charvaka accepts only one pramana (perception). Nyaya accepts four. Mimamsa and Advaita Vedanta accept the maximum of six pramanas. Buddhism generally accepts only two (perception and inference). This table is extremely high-yield for Prelims.

Influence on Modern Thought

Philosopher / Thinker Influence
Swami Vivekananda Popularised Advaita Vedanta globally; addressed Parliament of Religions (Chicago, 1893)
Mahatma Gandhi Drew on ahimsa (Jainism/Buddhism), karma yoga (Bhagavad Gita), and satya (truth) for political philosophy
Dr. B.R. Ambedkar Embraced Navayana Buddhism; critiqued caste from a philosophical standpoint
Sri Aurobindo Integral Yoga --- synthesis of Vedanta, Yoga, and evolutionary philosophy
S. Radhakrishnan Interpreted Indian philosophy for Western audiences; served as India's 2nd President
Amartya Sen Drew on Indian philosophical traditions of argumentation (Nyaya) and pluralism (Anekantavada) in works on justice and development

Key Terms for Quick Revision

Term Meaning
Darshana Philosophical school; literally "seeing/vision"
Astika Orthodox schools that accept Vedic authority
Nastika Heterodox schools that reject Vedic authority
Pramana Means of valid knowledge (perception, inference, testimony, etc.)
Purusha Pure consciousness/self (Sankhya/Yoga)
Prakriti Primordial matter/nature (Sankhya/Yoga)
Advaita Non-dualism (Shankaracharya) --- Atman = Brahman
Vishishtadvaita Qualified non-dualism (Ramanuja)
Dvaita Dualism (Madhva) --- God, souls, and matter are eternally distinct
Anekantavada Many-sidedness doctrine (Jainism)
Pratityasamutpada Dependent origination (Buddhism)
Paramanu-vada Atomic theory (Vaisheshika)
Prasthanatrayi Triple canon of Vedanta: Upanishads, Brahma Sutras, Bhagavad Gita

Exam Strategy

For Mains Answer Writing: Indian philosophy questions in GS-I and Essay often test conceptual understanding rather than rote facts. Structure answers around: (1) the school's core metaphysical position, (2) its epistemology (pramanas), (3) its path to moksha, and (4) its contemporary relevance. Comparison questions (Advaita vs. Dvaita, or Indian vs. Greek philosophy) are common --- use tables to organise differences clearly.

For Prelims: Focus on founder-text-school matching: Gautama-Nyaya Sutras, Kanada-Vaisheshika Sutras, Kapila-Sankhya, Patanjali-Yoga Sutras, Jaimini-Mimamsa Sutras, Badarayana-Brahma Sutras. Remember the number of pramanas accepted by each school (Nyaya: 4, Mimamsa: 6, Charvaka: 1). Know the three sub-schools of Vedanta and their proponents.

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