The Upanishads

The word upanishad is often explained as upa (near) + ni (down) + shad (to sit): sitting down near a teacher to receive a teaching. Adi Shankaracharya explains it as the knowledge that destroys ignorance and leads to Brahman. In content, the Upanishads move from the outer fire ritual of the Vedas to an inner question: what is the Self, and what is the ground of all that exists?

Because they come at the end of each Veda, and because they state the Vedas' final purpose, they are called Vedanta. They are shruti in the full sense. Together with the Bhagavad Gita (smriti) and the Brahma Sutras (the systematic summary of Upanishadic teaching), they form the Prasthana Trayi, the three foundational sources on which every school of Vedanta builds its commentary.

More than two hundred texts carry the name Upanishad. The Muktika Upanishad, in which Rama teaches Hanuman, gives the traditional list of 108, grouped by the Veda to which each belongs. Of these, a small group are the oldest and most authoritative. Adi Shankaracharya wrote commentaries on ten of them, and many lists add the Shvetashvatara, Kaushitaki and Maitri to make thirteen. The many later Upanishads include texts on yoga, renunciation (sannyasa), and devotion to Vishnu, Shiva and Devi.

In tradition the Upanishads, like the rest of the Veda, are apaurusheya, not authored by humans. Yet they are full of named teachers and seekers: Yajnavalkya, Uddalaka Aruni, the princess-sage Gargi Vachaknavi, Maitreyi, King Janaka of Videha, the boy Nachiketa, Satyakama Jabala. Their teachings are presented as passed down in an unbroken line from teacher to student, and some Upanishads end with that lineage.

Historians place them over many centuries. Following the Indologist Patrick Olivelle, the Brihadaranyaka and Chandogya are generally considered the earliest, probably pre-Buddhist, around the 7th–6th centuries BCE; the Taittiriya, Aitareya and Kaushitaki follow; and the verse Upanishads such as the Kena, Katha, Isha, Shvetashvatara and Mundaka are placed in the last centuries BCE. Some scholars argue for later dates. The minor Upanishads were composed much later, some well into the second millennium CE. Scholars stress that these are broad estimates, not firm dates.

Brahman and Atman. Brahman is the infinite reality underlying everything; Atman is the true Self in each being. The central insight of the Upanishads is that these are not two: the Self within is the reality of the whole. Four sayings, one from each Veda, are traditionally honoured as the mahavakyas (great sayings): 'prajnanam brahma' (Aitareya, Rigveda), 'aham brahmasmi' (Brihadaranyaka, Yajurveda), 'tat tvam asi' (Chandogya, Samaveda) and 'ayam atma brahma' (Mandukya, Atharvaveda).

Karma, rebirth and moksha. The Upanishads give some of the earliest clear statements that actions shape future births, and that liberation (moksha) from the cycle comes through knowledge of the Self, not through ritual alone.

The great dialogues. Nachiketa refuses all the wealth Yama offers and insists on learning what lies beyond death (Katha). Yajnavalkya, before leaving for the forest, tells his wife Maitreyi that 'it is not for love of the husband that the husband is dear, but for love of the Self' (Brihadaranyaka). Uddalaka asks his son to dissolve salt in water and taste it: the salt cannot be seen, yet it is everywhere, as the Self is in all things (Chandogya).

The Vedanta schools read these teachings differently. Advaita (Shankaracharya) sees complete identity of Atman and Brahman; Vishishtadvaita (Ramanujacharya) sees the Self as a real part of Brahman; Dvaita (Madhvacharya) holds that the soul and God are eternally distinct. Each is a living tradition with its own reading of the same texts.

Four well-known passages, with the Sanskrit as given on Sanskrit Wikisource.

The Upanishads are chanted as part of Vedic recitation, and their Shanti mantras, such as 'om purnamadah purnamidam' (which opens the Isha Upanishad) and 'om saha navavatu' (Taittiriya), are recited before study and at many ceremonies. 'Asato ma sadgamaya' is among the most widely recited prayers in Hindu homes and schools.

In the traditional way, the Upanishads are studied with a teacher and a classical commentary (bhashya), through shravana (listening), manana (reflection) and nididhyasana (contemplation). Monastic orders and study centres across India and abroad hold regular classes. Their influence also travelled far: the Mughal prince Dara Shikoh had fifty Upanishads translated into Persian in 1657, and through a Latin version of that translation they reached European philosophers such as Arthur Schopenhauer.

Start with a short one. The Isha (18 verses) and the Kena are easy to read in one sitting, and the Katha, with Nachiketa's story, is the best-loved introduction. Then read the Mundaka and Mandukya, and finally the long Chandogya and Brihadaranyaka.

Gita Press, Gorakhpur publishes the Ishadi Nau Upanishad, with Sanskrit text and Hindi meaning, which is widely used in Hindu homes. In English, Patrick Olivelle's 'Upanisads' (Oxford World's Classics) is a reliable scholarly translation of the early texts, and Swami Nikhilananda's and Swami Gambhirananda's translations (the latter with Shankara's commentary, Advaita Ashrama) present the traditional Advaita reading. The Sanskrit text is freely available on Sanskrit Wikisource.