The Upanishads have been rightly termed the Himalayas of the soul. They represent the heights to which the spirit of man soared in this country in its contemplation of the Divine Spirit. They contain the experience of the seers and saints of India who lived about three thousand years ago.
It cannot be stressed too often that the Upanishads are the revelations vouchsafed not to a single prophet but to the seers of a whole age, which is one of the most brilliant in the annals of mankind.They are inspired utterances, the results not of a logical but of a poetic approach to reality. Accordingly we do not have a single uniform system of thought emerging out of their teachings.
On the contrary, as the history of Hinduism shows, we have here several levels of thought and experience which gave rise in course of time to several schools of philosophy and several streams of religious tradition. At the same time it is obvious that not all the truths taught here are equally prominent. Some are only half-way houses on the path leading to the Absolute.
It is well-known that the Upanishads constitute the last phase of the Vedic revelation. The Mantras constitute the first phase, the Brahmanas the second, the Aranyakas the third, and the Upanishads the fourth and the last.
The Upanishads come at the end of the Veda and the teachings they embody are known as the Vedanta. But there is no hard and fast line drawn between one phase and another. Nor is there any inner contradiction between them. There is only change of emphasis.
If the Brahmanas develop the ritualistic elements in the Mantras, the Aranyakas and the Upanishads develop the mystical elements in them. It is a mistake to suppose that the Upanishads in any manner intend to break away from the earlier phases of the Veda.
Such a thing is unknown to the Hindu religious tradition. Therein lies perhaps the secret of its strength. The very fact that the Upanishadic teachers often quote verses from the Vedic hymns in support of their teachings shows that no new departure was contemplated by them. Also, occasionally we have in the longer Upanishads, as in the Brahmanas, discussions on such details of the sacrifices as the number of offerings to be made, the duties to be discharged by the various officiating priests, the hymns to be sung and the gods to be involved.
At this time we may not be interested in these discussions and may even regard them as a hindrance to our appreciation of the poetry and the philosophy of the Upanishads, but they were of tremendous importance to the men of that age. For it was believed at the time that any error in the performance of a sacrifice or any misunderstanding of the import of a mantra might result in the falling off of the priest’s head. In fact, it is only when we are able to make due allowance for the mass of local and temporary beliefs of the age and look through them at the universal and eternal truths taught by the Upanishadic seers that we are in a position to appreciate the originality and the courage of those teachers.They were apparently engaged in the mighty task of transforming a rather low type of sacrificial religion prevalent at the time into a great mystical religion true for all times, without in any explicit manner breaking away from the traditions of the past.
And they succeeded in this to such an extent that their teaching, with its later developments and offshoots spread not only over the whole subcontinent of India but also over many of the islands and countries of the Far East. Indeed it became the basis of one of the greatest religious traditions that the world has ever known.