In short, the teachers of the Upanishads not only do not declare clearly what they believed in regard to cosmogonic and eschatological matters, but many of them probably did not know clearly what they believed. Their great discovery was that man's spirit was not particular and mortal, but part of the immortal universal. Whether this universal was a being alive and a personal _[=a]tm[=a]_, or whether this personal being was but a transient form of impersonal, imperishable being;[31] and whether the union with being, _brahma_, would result in a survival of individual consciousness,--these are evidently points they were not agreed upon, and, in all probability, no one of the sages was certain in regard to them. Crass identifications of the vital principle with breath, as one with ether, which is twice emphasized as one of the two immortal things, were provisionally accepted. Then breath and immortal spirit were made one. Matter had energy from the beginning, _brahma_; or was chaos, _asat_, without being. But when _asat_ becomes _sat_, that _sat_ becomes _brahma_, energized being, and to _asat_ there is no return. In eschatology the real (spirit, or self) part of man (ego) either rejoices forever as a conscious part of the conscious world-self, or exists immortal in _brahma_--imperishable being, conceived as more or less conscious.[32]
The teachers recognize the limitations of understanding: "The gods are in Indra, Indra is in the Father-god, the Father-god (the Spirit) is in _brahma_"--"But in what is _brahma?_" And the answer is, "Ask not too much" (_Brihad. [=A]ran. Up_. 3. 6).
These problems will be those of the future formal philosophy. Even the Upanishads do not furnish a philosophy altogether new. Their doctrine of _karma_ their identification of particular ego and universal ego, is not original. The 'breaths,' the 'nine doors,' the 'three qualities,' the _purusha_ as identical with ego, are older even than the Br[=a]hmanas (Scherman, _loc. cit_. p. 62).
It is not a new philosophy, it is a new religion that the Upanishads offer.[33] This is no religion of rites and ceremonies, although the cult is retained as helpful in disciplining and teaching; it is a religion for sorrowing humanity. It is a religion that comforts the afflicted, and gives to the soul 'that peace which the world cannot give.' In the sectarian Upanishads this bliss of religion is ever present. "Through knowing Him who is more subtile than subtile, who is creator of everything, who has many forms, who embraces everything, the Blessed Lord--one attains to peace without end" (_Çvet_. 4. 14-15). These teachers, who enjoin the highest morality ('self-restraint, generosity, and mercy' are God's commandments in _Brihad [=A]ran_. 5. 2) refuse to be satisfied with virtue's reward, and, being able to obtain heaven, 'seek for something beyond.' And this they do not from mere pessimism, but from a conviction that they will find a joy greater than that of heaven, and more enduring, in that world where is "the light beyond the darkness" (_Çvet_. 3. 8); "where shines neither sun, moon, stars, lightning, nor fire, but all shines after Him that shines alone, and through His light the universe is lighted" (_Mund_. 2. 2. 10). This, moreover, is not a future joy. It is one that frees from perturbation in this life, and gives relief from sorrow. In the Ch[=a]ndogya (7. 1. 3) a man in grief comes seeking this new knowledge of the universal Spirit; "For," says he, "I have heard it said that he who knows the Spirit passes beyond grief." So in the [=I]ç[=a], though this is a late sectarian work, it is asked, "What sorrow can there be for him to whom Spirit alone has become all things?' (7). Again, "He that knows the joy of _brahma_, whence speech with mind turns away without apprehending it, fears not" (_T[=a]itt_. 2. 4); for "fear comes only from a second" (_Brihad [=A]ran. Up_. 1. 4. 2), and when one recognizes that all is one he no longer fears death (_ib_. 4. 4. 15).