Nyaya
न्यायFounder: Gautama (Akṣapāda) · Text: Nyāya Sūtras (~2nd c. BCE), with Vātsyāyana's Bhāṣya; later the Navya-Nyāya ("new logic") of Gangesha.
The school of logic and epistemology - right knowledge (pramā) is the path to liberation, and clear reasoning is how truth is established and error removed.
4 pramāṇas (means of knowledge) - Pratyakṣa (perception), Anumāna (inference), Upamāna (comparison), Śabda (valid testimony).
16 categories (padārthas) - From pramāṇa and prameya (the knowable) through doubt, purpose, debate, fallacy, to liberation - a full map of reasoning and disputation.
The 5-membered syllogism - Proposition, reason, example, application, conclusion - India's formal logic, sharper in some ways than Aristotle's.
Liberation - Mokṣa is the absolute cessation of suffering, reached by true knowledge of the categories - removing the false knowledge that binds.
Pairs with Vaiśeṣika (Nyāya supplies the logic, Vaiśeṣika the objects) - together "Nyāya-Vaiśeṣika".
Vaisheshika
वैशेषिकFounder: Kaṇāda (Ulūka) · Text: Vaiśeṣika Sūtras (~2nd c. BCE), with Praśastapāda's commentary.
The school of atomism and categories - all reality is classified into a few padārthas, and the physical world is built from indivisible, eternal atoms (paramāṇu).
Atomism (paramāṇu-vāda) - Matter is made of eternal, indivisible atoms of earth, water, fire and air; they combine (dyad, triad…) to form everything - anticipating atomic theory by millennia.
7 categories (padārthas) - Dravya (substance), Guṇa (quality), Karma (action), Sāmānya (universal), Viśeṣa (particular - the namesake), Samavāya (inherence), Abhāva (absence).
9 substances - Earth, water, fire, air, ether (ākāśa), time, space, self (ātman), mind (manas).
Liberation - Liberation comes from true knowledge of the categories, ending the cycle of merit and demerit that drives rebirth.
The metaphysical partner of Nyāya - it describes what exists; Nyāya describes how we validly know it.
Purva Mimamsa
पूर्व मीमांसाFounder: Jaimini · Text: Mīmāṃsā Sūtras (~3rd c. BCE), with Śabara's Bhāṣya; later the Bhāṭṭa (Kumārila) and Prābhākara schools.
The school of Vedic exegesis - its purpose is to establish dharma, defined as what the Veda enjoins. It develops the rules for interpreting ritual injunction and the philosophy of action.
Dharma = Vedic injunction - Right action is known from the Veda's commands (vidhi); the Mimamsakas built the science of how to read and apply them.
Apūrva - The unseen potency a ritual generates, which fructifies as its later result - an early theory of how karma "stores".
Eternity of the Veda + word - The Veda is authorless (apauruṣeya) and eternal; the bond between word and meaning is intrinsic, not conventional.
6 pramāṇas - Adds Arthāpatti (postulation) and Anupalabdhi (non-apprehension) to the four of Nyāya.
Liberation - Classical Purva Mimamsa focused on dharma and heaven (svarga) through right action; later Mimamsakas incorporated mokṣa. Its sister school, Uttara Mimamsa, is Vedanta - the inquiry into Brahman.
The "earlier inquiry" (into action/ritual) that precedes Uttara Mimamsa / Vedanta (the "later inquiry" into Brahman).
