When we hear the word, upaniṣad our most immediate response is "ātman=brahman" because that is indeed the central and most powerful philosophical idea of the upaniṣad. This idea is so overpowering that it eclipses everything else recorded in the upaniṣads. The upaniṣads are in fact complex, varied texts that address even the everyday concerns of human beings, like how to attract the affection of a woman you like and observations about the cosmic fire within us which we can hear if we press our ears closes with our fingers. (Try it!)
They were composed at a time of tremendous social, economic and religious upheaval, and they document the transition of Hinduism from the ritualism of the early Vedic era to the emergence of central religious concepts that define the religion as we know it today. Ideas such as the law of karma regulating the rebirth process, and the techniques of liberation from the cycle of rebirth. Generally, the early Vedic corpus comes to be called karmakāṇḍa (ritual) and the upaniṣads are called the jñānakāṇḍa (salvific knowledge).
The earliest upaniṣads are generally regarded as pre-buddhistic and are written in prose. Later texts are written in verse and display distinct theistic tendencies. But the overwhelming theme is the rejection of external ritual as a path to salvation. Composed over a period of nearly 600 years, these texts are considered the most fundamental religious texts by almost all Hindus. Like the samhitas and the brāhmaṇas before them, the upaniṣads belong to specific Vedic śākhās (lit. branches) like so*:
In today's Twitter session we will be looking at a text that exemplifies a key upaniṣadic concept - that of 'bandhu' or equivalence. How do we get 'from me and you' to a single universal substratum? Let's find out in #SanksritAppreciationHour. Join me at 3pm GMT today on Twitter.
* Table is taken from the Wikipedia page on Upanishads.
