Buddha had no definite ideas of the deity, and the worship of a personal God is nowhere to be found in his teachings, which exposed him to the charge of atheism. He even supposed that gods were subject to death, and must return to other forms of life before they obtained final rest in Nirvana. Nirvana means that state which admits of neither birth nor death, where there is no sorrow or disease,--an impassive state of existence, absorption in the Spirit of the Universe. In the Buddhist catechism Nirvana is defined as the "total cessation of changes; a perfect rest; the absence of desire, illusion, and sorrow; the total obliteration of everything that goes to make up the physical man." This theory of re-births, or transmigration of souls, is very strange and unnatural to our less imaginative and subtile Occidental minds; but to the speculative Orientals it is an attractive and reasonable belief. They make the "spirit" the immortal part of man, the "soul" being its emotional embodiment, its "spiritual body," whose unsatisfied desires cause its birth and re-birth into the fleshly form of the physical "body,"--a very brief and temporary incarnation. When by the progressive enlightenment of the spirit its longings and desires have been gradually conquered, it no longer needs or has embodiment either of soul or of body; so that, to quote Elliott Coues in Olcott's "Buddhist Catechism," "a spirit in a state of conscious formlessness, subject to no further modification by embodiment, yet in full knowledge of its experiences [during its various incarnations], is Nirvanic."