The explanation of dreamless sleep as supreme bliss and Yajnavalkya’s statement that the soul after death cannot be said to know or feel, may suggest that union with Brahman is another name for annihilation.  But that is not the doctrine of the Upanishads though a European perhaps might say that the consciousness contemplated is so different from ordinary human consciousness that it should not bear the same name.  In another passage[191] Yajnavalkya himself explains “when he does not know, yet he is knowing though he does not know.  For knowing is inseparable from the knower, because it cannot perish.  But there is no second, nothing else different from him that he could know.”  A common formula for Brahman in the later philosophy is Saccidananda, Being, Thought and Joy[192].  This is a just summary of the earlier teaching.  We have already seen how the Atman is recognized as the only Reality.  Its intellectual character is equally clearly affirmed.  Thus the Brihad-Aranyaka (III. 7. 23) says:  “There is no seer beside him, no hearer beside him, no perceiver beside him, no knower beside him.  This is thy Self, the ruler within, the immortal.  Everything distinct from him is subject to pain.”  This idea that pain and fear exist only as far as a man makes a distinction between his own self and the real Self is eloquently developed in the division of the Taittiriya Upanishad called the Chapter of Bliss.  “He who knows Brahman” it declares, “which exists, which is conscious, which is without end, as hidden in the depth of the heart, and in farthest space, he enjoys all blessings, in communion with the omniscient Brahman....  He who knows the bliss (anandam) of that Brahman from which all speech and mind turn away unable to reach it, he never fears[193].”

Bliss is obtainable by union with Brahman, and the road to such union is knowledge of Brahman.  That knowledge is often represented as acquired by tapas or asceticism, but this, though repeatedly enjoined as necessary, seems to be regarded (in the nobler expositions at least) as an indispensable schooling rather than as efficacious by its own virtue.  Sometimes the topic is treated in an almost Buddhist spirit of reasonableness and depreciation of self-mortification for its own sake.  Thus Yajnavalkya says to Gargi[194]:  “Whoever without knowing the imperishable one offers oblations in this world, sacrifices, and practises asceticism even for a thousand years, his work will perish.”  And in a remarkable scene described in the Chandogya Upanishad, the three sacred fires decide to instruct a student who is exhausted by austerities, and tell him that Brahman is life, bliss and space[195].

Analogous to the conception of Brahman as bliss, is the description of him as light or “light of lights.”  A beautiful passage[196] says:  “To the wise who perceive him (Brahman) within their own self, belongs eternal peace, not to others.  They feel that highest, unspeakable bliss saying, this is that.  How then can I understand it?  Has it its own light or does it reflect light?  No sun shines there, nor moon nor stars, nor these lightnings, much less this fire.  When he shines everything shines after him:  by his light all the world is lighted.”