The Upanishads are believed to be a commentary on the secret doctrine of the Vedas but no one has so far been able to establish the correctness of this ancient belief. We have shown how the gods of the Vedas personify the great creative energies of the universe, and how the idea of the different systems of Philosophy is based on them; and now we shall see how the Upanishads deal with the same subject too.
The exact number of the Upanishads is not known, but there are said to be more than a hundred of them. They are attached to the Brahmanas and have for their object the explanation of the secret meaning of the Vedas, and they are believed to be a direct source of all systems of Hindu Philosophy, from Sankhya to Vedanta. If this be really true, we should find in them the different theories of the creation of the universe, and a treatment of the great creative energies of life, which constitute the bases of the great systems of Hindu Philosophy, in the light God, Nature, individual soul, and knowledge and action as the goals of life, as we have explained. Let us examine them in this light.
The Origin of the Universe: We have observed that the ancients believed that it is impossible to know the origin and end of things; but, arguing from the known to the unknown, we might say that the universe is created by Purusha alone, or Prakrti alone, or by the union together of the two and this gives us the three principal and five resultant systems of Hindu Philosophy. Corresponding to this the Upanishads tell us that "verily in the beginning all this was Self (Purusha)"; again we are told that "all this was Water", and Water, as we have seen, symbolizes Nature or Prakrti; and then it is said that, "he was as large as a man and wife (Purusha and Prakrti) together; he made his self to fall into two, and thence arose husband and wife"; and this obviously refers to the union of Purusha and Prakrti in the creation of life. Sometimes we are told that Purusha creates Prakrti, symbolized as Water; and again it is said that Prakrti is the creator of all life as well as Purusha; and then, as we have seen, the two are conceived as united together in one as man and wife.
Creation as a Sacrifice: We have explained how the idea of Sacrifice is vital to the creation of life by God; and, as we shall see, the Brahmanas deal with it at considerable length. Its origin is to be traced to the Rig Veda, and the same idea occurs in the Upanishads too. Man himself is called a Sacrifice; and the offering, it is said, which is offered in the fire, goes to the Sun and from thence returns in the form of food, from which is the birth of all beings; and so it is Sacrifice that is the cause of the creation of life. Sacrifice is also called Brahmacharya, which literally means, "acting like Brahma" the supreme Creator of the universe; and so the supreme Sacrificer is said to be the Lord himself.
The Order of Creation in the Upanishads: We have explained the order of creation as consisting of twenty-four, twenty-five or twenty-six principles or "topics" according to different systems of Hindu Philosophy as including the supreme Purusha, Prakrti, the individual soul, Buddhi, Egoism, Mind, the five subtle and five gross elements, and the five senses of knowledge and five of action. The origin of this has been traced to the Vedas in the description of the gods hymned therein, and the same idea is to be found in the Upanishads in yet clearer terms.
We have observed that the Upanishads refer the origin of all life to Purusha, or Prakrti, or else the union together of the two and now we are told that in the beginning all this was Self. He thought, "Shall I send forth the worlds?" He then sent forth Water (Prakrti) which is the support of heaven. He then formed the Purusha (individual soul) taking him forth from the Water. He then brooded on him, whereupon arose Speech, and from speech Agni. Nostrils burst forth, and from nostrils Prana (breath) and from Prana Vayu (Air) Eyes burst forth, and from eyes sight, and from sight the Sun. Ears burst forth, and from ears hearing, and from hearing Ether or Space. Skin burst forth, and from skin the sense of touch. The heart burst forth, and from the heart Mind, and from the Mind the Moon. The navel burst forth, and from the navel the down-breathing air (Apana), and from that Death. The generative organ burst forth, and from that Seed; and from Seed Water (Prakrti).
In this we have the whole idea of creation expressed in different ways in the different schools of Hindu Philosophy. We have (1) the Supreme Purusha or the Self and he creates (2) Water or Prakrti. Then arises (3) Purusha or the individual soul, dwelling in the Heart, and associated with Water or Prakrti and so characterised by (4) Egoism or Ahankara. Then we have Buddhi or the Sun; Mind or the Moon; the elements, subtle and gross, and the senses of knowledge and action.