There are four (out of the many other) names of the various kinds of Esoteric Knowledge or Sciences given, even in the exoteric Puranas. There is (1) _Yajna-Vidya_,[C] knowledge of the occult powers awakened in Nature by the performance of certain religious ceremonies and rites. (2) _Maha-Vidya_, the "great knowledge," the magic of the Kabalists and of the _Tantrika_ worship, often Sorcery of the worst description. (3) _Guhya-Vidya_, knowledge of the mystic powers residing in Sound (Ether), hence in the _Mantras_ (chanted prayers or incantations) and depending on the rhythm and melody used; in other words a magical performance based on Knowledge of the Forces of Nature and their correlation; and (4) Atma-Vidya, a term which is translated simply "Knowledge of the Soul," _true Wisdom_ by the Orientalists, but which means far more. This last is the only kind of Occultism that any Theosophist who admires _Light on the Path_, and who would be wise and unselfish, ought to strive after. All the rest is some branch of the "Occult Sciences," i.e., arts based on the knowledge of the ultimate essence of all things in the Kingdom of Nature--such as minerals, plants, and animals--hence of things pertaining to the realm of _material_ Nature, however invisible that essence may be, and howsoever much it has hitherto eluded the grasp of Science. Alchemy, Astrology, Occult Physiology, Chiromancy exist in Nature, and the _exact_ Sciences--perhaps so called because they are found in this age of paradoxical philosophies the reverse--have already discovered not a few of the secrets of the above _arts_. But clairvoyance, symbolized in India as the "Eye of Siva," called in Japan, "Infinite Vision," is _not_ Hypnotism, the illegitimate son of Mesmerism, and is not to be acquired by such arts. All the others may be mastered and results obtained, whether good, bad, or indifferent; but _Atma-Vidya_ sets small value on them. It includes them all, and may even use them occasionally, but it does so after purifying them of their dross, for beneficent purposes, and taking care to deprive them of every element of selfish motive. Let us explain: Any man or woman can set himself or herself to study one or all of the above specified "Occult Arts" without any great previous preparation, and even without adopting any too restraining mode of life. One could even dispense with any lofty standard of morality. In the last case, of course, ten to one the student would blossom into a very decent kind of sorcerer, and tumble down headlong into black magic. But what can this matter? The _Voodoos_ and the _Dugpas_ eat, drink and are merry over hecatombs of victims of their infernal arts. And so do the amiable gentlemen vivisectionists and the _diploma-ed_ "Hypnotizers" of the Faculties of Medicine; the only difference between the two classes being that the Voodoos and the Dugpas are _conscious_, and the Charcot-Richet crew _unconscious_ Sorcerers.