It is remarkable that the age of the Vedas was followed by the age of the Upanishads in the history of India. For it was in the age of the Upanishads that the Rishis discovered the essential processes of the yoga contained in the Vedic Samhitas, and they reaffirmed by the Yogic methods the truths that were discovered by the Vedic Rishis. The effort of the Upanishadic Rishis may be regarded as an effort of the recovery of the Vedic knowledge as also an effort of confirmation of the Vedic knowledge. As in science, so in Yoga which is also a science, the ultimate proof of experience lies in conformation and even of modification and expansion of the knowledge gained and accumulated in the past. Thus the Vedic knowledge stands proved by the affirmations of the Upanishads.
A comparative study of the Vedas and the Upanishads will show that the Upanishads continue the Vedic effort of Yoga and the Upanishads provided to the Indian people a sure foundation of their own special genius. We find in the Upanishads the real budding of the soul of India, which has been continuously striving to bloom to its fullness during the long course of its history.
Fortunately, in the writings of Sri Aurobindo we find an authentic account of the gradual blooming of the lotus of the bud of Yoga, which was itself a part of the germination of the seed that was sown in India by the Rishis of the Veda.