In course of time this nature-worship of the Vedic period developed into a sort of pantheism, that is, a system which identifies God with the universe. This form of the Indian religion is known as Brahmanism. Brahma, an impersonal essence, is conceived as the primal existence. Forth from Brahma emanated, as heat and light emanate from the sun, all things and all life. Banish a personal God from the universe, as some modern scientists would do, leaving nothing but nature with her original nebula, her endless cycles, her unconscious evolutions, and we have something very like Brahmanism. A second, fundamental conception of Brahmanism is that all life, apart from Brahma, is evil, is travail and sorrow. We can make this idea intelligible to ourselves by remembering what are our own ideas of this earthly life. We call it a feverish dream, a journey through a vale of sorrow. Now the Hindu regards _all_ conscious existence in the same light. He has no hope in a better future; so long as the soul is conscious, so long must it endure sorrow and pain. This conception of all conscious existence as necessarily and always evil, leads naturally to the doctrine that it is the part of wisdom and of duty for man to get rid of consciousness, to annihilate himself, in a word, to commit soul-suicide. Brahmanism teaches that the only way to extinguish self and thus get rid of the burden of existence, is by re-absorption into Brahma. But this return to Brahma is dependent upon the soul's purification, for no impure soul can be re-absorbed into the primal essence. The necessary freedom from passion and the required purity of soul can best be attained by self-torture, by a severe mortification of the flesh; hence the asceticism of the Hindu devotee. As only a few in each generation reach the goal, it follows that the great majority of men must be born again, and yet again, until all evil has been purged away from the soul and eternal repose found in Brahma. He who lives a virtuous life is at death born into some higher caste, and thus he advances towards the longed-for end. The evil man, however, is born into a lower caste, or perhaps his soul enters some unclean animal. This doctrine of re-birth is known as the transmigration of souls (metempsychosis). Only the first three classes are admitted to the benefits of religion. The Sudras and the outcasts are forbidden to read the sacred books, and for any one of the upper classes to teach a serf how to expiate sin is a crime.