Vishnu Vishvarupa, India; Rajasthan state, former kingdom of Jaipur (1800–1820)
"During the early vedic period the universe was viewed as consisting of three spheres (loka): the earth, the sky or firmament, and the space between these two, the intermediate region. The ancient Indians shared this tripartite cosmology with other Indo-European peoples. The phenomena associated with the sky and the intermediate region drew the attention of the early vedic poets in a special way: the rain clouds, lightning, thunder, wind, storm, and rain in the intermediate region, and the sun, moon, stars, and the brilliant vault of heaven in the sky.
This tripartite universe was controlled by personal powers, the gods. For the most part, these gods are associated with their natural counterparts, such as the sun, moon, storm, rivers, and fire. Often the Sanskrit names of the gods are identical to the names of the corresponding cosmic entity; thus, Surya is the Sun and Agni is the Fire. Sometimes the names vary, but the connection with the cosmic phenomena is unmistakable; thus Indra is connected with thunder and the releasing of waters; his weapon is the thunderbolt.
In the early vedic period the gods themselves are distributed among the three spheres: there are the gods of the earth, the gods of the intermediate region, and the gods of the sky. Although this distribution persists, the gods came to be generally located in the sky, the realm of light and immortality. The Sanskrit terms for these three spheres—bhur, bhuvas, svar—became sacred sounds, possibly because they contained the totality of the universe. Much Upanisadic speculation centers on the hidden meaning of these sounds.
In recent studies of vedic cosmology, Witzel (1984) and Brereton (1991) have drawn attention to the importance of the Milky Way and the stars around the polestar. Witzel has shown that the expression svarga loka (lit., 'bright world' commonly translated as 'heavenly world') refers specifically to the Milky Way. The door to this world is located at the mouth of the two arms extending toward the east from the Milky Way viewed during the winter months in northern India, which explains the importance of the east and the northeast in the ritual and in cosmological speculations. The Milky Way is also the bright ocean of heaven, the celestial waters; it is the source of the rivers that flow from the Himalayan mountains, thus connecting the earthly to the celestial waters.
By the late vedic period, however, we note the emergence of a new plan of the universe with seven spheres, positing three farther regions beyond the sky, called Mahas, Janas, and Tapas, and the farthest world named Satyaloka ('world of truth') or Brahmaloka ('world of Brahman'). Parallel to these seven upper or pleasant worlds, texts from a much later period posit seven descending and unpleasant worlds or hells, but the Upanisads show no sign of such a conception.
Another conception of the universe divides it into the world of humans, the world of ancestors or fathers, and the world of gods. Although less tied to observable reality, it is more significant for beliefs regarding the afterlife. The world of humans is, of course, the observable world in which our normal lives are lived. During the early period all humans, or at least those who had lived a ritually correct life, were believed to go to the world of fathers, but the Upanisads reveal a new perception of that world, according to which only those who are destined to return to and to be reborn in this world follow the path to the world of the fathers, while those destined not to return and to become immortal proceed to the world of the gods.
This new conception is tied to an emergent worldview centered on the doctrine of rebirth. The manner in which the rebirth process was thought to operate is similar to that in which Brahmanical thought viewed the operation of ritual actions. Rites achieve their results by their own autonomous power and according to a ritual law of cause and effect; ritual success does not depend on the will of a god. The moral law that governs the rebirth process operates in a similar manner; those who perform good actions are reborn in good situations, while those who do the opposite proceed to evil births. The correlation between the ritual and ethical spheres apparent in these early texts is made easier by the fact that the same Sanskrit term, karman (lit. 'action'), is used for both ritual and moral actions. The ethicization of cosmic processes evident in the Upanisads, moreover, remains a constant feature of later Indian cosmologies.
The early view of the mechanism of rebirth and of the escape from the rebirth cycle as depicted in the famous doctrine of five fires is tied to the old view of a tripartite and enclosed universe. The firmament, the vault of heaven, is viewed as a solid cover. After they are cremated, humans destined to be reborn go up to the moon in the form of smoke or vapor; from there they return to earth as rain, enter plants, and, when they are eaten by a man, become semen. They finally take on a new life in the womb of a woman. The universe is thus a prison with walls above (firmament) and below (earth). Those who possess the liberating knowledge, however, are able to break this cycle, to escape from this prison. The sun is viewed as a lid that covers the only opening in the vault of heaven, the only door to freedom; the sun permits the liberated individuals to pass through that opening and escape to the immortal condition outside the universe.
Another central concern of the Upanisadic thinkers relates to the "beginnings"; the expression "in the beginning" (agre) is frequent and opens the narrative of creation stories. The creator, the source from which creation emerged, most often is Prajapati, the principal creator god of the Brahmanas, who is identified with the sacrifice itself. The other two principles located at the "beginning" with some frequency are Brahman and Atman, which I will discuss below.
By the time of the later verse Upanisads, such as the Svetasvatara, new and more theoretical cosmologies had emerged, the most prominent of which is that associated with the Samkhya and Yoga traditions. Since these are some of the oldest documents reflecting Samkhya conceptions of the universe, the precise cosmology underlying them is unclear; that cosmology is certainly different from the classical accounts of Samkhya cosmology contained in scholastic works of later times. Like the latter, however, this early cosmology posits a material source, a primal matter, called prakrti or pradhana. This primal matter, originally unmanifest, contains three qualities or strands (guna): goodness (sattva), energy (rajas), and darkness (tamas).The visible and manifest universe has proceeded from the original primal matter; the three qualities are distributed in different proportions within the various constituents of the universe. Unlike classical Samkhya, however, this early cosmology posits a single and unique god who rules over the primal matter and regulates the production of the visible universe from it. Besides primal matter and god, there are the individual souls of humans, souls that are trapped within material bodies produced by primal matter. It is through the help of god that these souls can hope to be liberated from the material prison.
— Patrick Olivelle, "The Early Upanishads: Annotated Text and Translation" (1998)