We have observed that there are five great creative energies of life Soul, Buddhi, Mind, Purushic and Prakrtic Ether or the senses of knowledge and action and all that appertains to them; and of these the last is transformed into Food or the vital energy in man. The Upanishads, like the different systems of Philosophy based on them, should deal with all problems relating to God, Nature, individual soul, and knowledge and action as the goals of life, in the light of each of these energies. Let us see if they tell us anything about these creative energies, and then we shall see how the latter are connected with the different problems of life.
The Soul: The Soul is often spoken of as the Self in the Upanishads. He is said to be the supreme creator of life and abides in the Heart, and it is from him that all forms of life issue forth.
Buddhi: Buddhi, as we have explained, is characterised by the power of thought as well as Tapas or Heat. Corresponding to this we are told that in the beginning all this was Self, and he created the worlds by the power of his thought again it is said that he enters the elements with his living self by means of his thought; and then we find that the Brahman swells by means of his Tapas, whence arise different forms of life.
Mind: We have observed that the Mind is characterised by Desire and Desire is its creative energy. Corresponding to this we are told that "He wished, may I be many, may I grow forth. He then practised Tapas, and created all forms of life". Again it is said that in Brahman all desires are contained; it is the Self which desires nothing but what it ought to desire, and it is this Brahman who creates the universe. He desires different kinds of worlds, and they all come up to him even according to his desire.
Purushic Ether: It is said that the Ether within the heart is the same as the ether around us; that in Ether everything is born, and towards Ether everything tends which is born; and that Ether is the revealer of all forms and names. This is the creative energy of Ether according to the Upanishads, to which the senses of knowledge correspond.
Prakrtic Ether or Food: We have explained how Prakrtic Ether is identified with the Prakrtic energy of the Heart or Food and so it is said that food is the root of the body; that from food are born all creatures that live on earth, afterwards they live on food, and in the end (when they die) they return to it and then we are told how the soul, descending from the kingdoms of the Sun and Moon to take its birth below, is transformed into grain, thence into vital seed, and then reborn as a creature in the world of life on earth.