This first epoch ended with the Upanishads, also called the Vedanta (ending of the Veda), which is a large, crowning outcome of the Vedic discipline and experience. Its cryptic symbols were removed and the language cast into a language of intuition, (intuition belongs to a plane higher than that of the intellect) not quite that of the intellect, but it wore a form of the intellect and was the starting point of the great number of philosophic speculations, debates and inquiries that were to originate in India later.
And so the first great age was a spiritual age, but spirituality itself does not live and flourish on this earth in a void, even as the lofty mountaintops donot rise out of the clouds in the skies without a base on the earth. Spirituality doesnot only shoot upwards towards the abstract, hidden and intangible, it also casts its rays downwards to embrace the richness and plentitudes of life. Therefore the second age was that of a stupendously-prolific creative age filled with an intellectual, ethical and dynamic will in life. Something in man had been awakened and he was ready to grasp more firmly the truths that were hidden behind the vedic symbols. These Truths held by the initiates broke its barriers and swept over the higher mind of man. Everywhere in India as well as the west, there was an intellectual outburst, a will to discover the reason and right way for all things of the mind. But in India, unlike the west, this seeking was always guided by the original spiritual impulse and never lost the touch of the religious sense. Philosophies worked out with the intellect and logic the same truths which had earlier been worked out by a more direct and luminous soul experience. The intensely beautiful, many-sided and many-thoughted epic literatures (Ramayana and Mahabharata) are full of an ethical thinking but always with an assent to the spiritual truths. Arts flourished, which dwelt much on life but their highest expression was that of a religious nature.
There was a gradual fading of the old Vedic symbols and a subtitution with novel forms. The house of fire was replaced by the temple, the Vedic godheads were replaced by the holy trinity, Brahma, Vishnu and Shiva, their vague forms with the more precise forms of Vishnu and Shiva and the ritual of sacrifice replaced with the beautiful temple worship. Though the outward forms are now completely different as that of a new religion, the principle and seed which it contains is still the same. The outward forms have to continually adapt and grow or even destroy themselves to give way to new forces, for the outward form, by its very nature, can never fully capture the essence of an idea; in the same way that the idea must continually adapt or change as no idea can ever completely formulate the spirit. Man could now understand the idea of the various personalities of these Gods, Brahma, Vishnu, shiva and a multitude of others, while all the time knowing that each god at the same time also contains the other gods within himself and also extends beyond them into the Infinite. Such was the suppleness and plasticity of the religion´s teaching.
Sources of inspiration and reference:
Sri Aurobindo´s Early cultural writings