Not any one may with his eye behold it:
By heart and mind and soul alone they grasp it,
And those who know it thus become immortal (vi. 9).
Since not by speech and not by thought,
Not by the eye can it be reached:
How else may it be understood
But only when one says “it is”? (vi. 12).
The place of the more personal Prajāpati is taken in the Upanishads by the Ātman as a creative power. Thus the Bṛihadāraṇyaka (I. iv.) relates that in the beginning the Ātman or the Brahma was this universe. It was afraid in its loneliness and felt no pleasure. Desiring a second being, it became man and woman, whence the human race was produced. It then proceeded to produce male and female animals in a similar way; finally creating water, fire, the gods, and so forth. The author then proceeds in a more exalted strain:—
“It (the Ātman) is here all-pervading down to the tips of the nails. One does not see it any more than a razor hidden in its case or fire in its receptacle. For it does not appear as a whole. When it breathes, it is called breath; when it speaks, voice; when it hears, ear; when it thinks, mind. These are merely the names of its activities. He who worships the one or the other of these, has not (correct) knowledge.... One should worship it as the Self. For in it all these (breath, etc.) become one.”
In one of the later Upanishads, the Çvetāçvatara (iv. 10), the notion, so prominent in the later Vedānta system, that the material world is an illusion (māyā), is first met with. The world is here explained as an illusion produced by Brahma as a conjuror (māyin). This notion is, however, inherent even in the oldest Upanishads. It is virtually identical with the teaching of Plato that the things of experience are only the shadow of the real things, and with the teaching of Kant, that they are only phenomena of the thing in itself.