Theosophy does not deny nor ignore the physical laws discovered by science. It admits all such as are proven, but it asserts the existence of others which modify the action of those we ordinarily know. Behind all the visible phenomena is the occult cosmos with its ideal machinery; that occult cosmos can only be fully understood by means of the inner senses which pertain to it; those senses will not be easily developed if their existence is denied. Brain and mind acting together have the power to evolve forms, first as astral ones in astral substance, and later as visible ones by accretions of the matter on this plane. Objectivity depends largely on perception, and perception may be affected by inner stimuli. Hence a witness may either see an object which actually exists as such without, or may be made to see one by internal stimulus. This gives us three modes of sight: (_a_) with the eye by means of light from an object, (_b_) with the inner senses by means of the Astral Light, and (_c_) by stimulus from within which causes the eye to report to the brain, thus throwing the inner image without. The phenomena of the other senses may be tabulated in the same manner. The Astral substance being the register of all thoughts, sounds, pictures, and other vibrations, and the inner man being a complete person able to act with or without coördination with the physical, all the phenomena of hypnotism, clairvoyance, clairaudience, mediumship, and the rest of those which are not consciously performed may be explained. In the Astral substance are all sounds and pictures, and in the Astral man remain impressions of every event, however remote or insignificant; these acting together produce the phenomena which seem so strange to those who deny or are unaware of the postulates of occultism. But to explain the phenomena performed by Adepts, Fakirs, Yogees, and all trained occultists, one has to understand the occult laws of chemistry, of mind, of force, and of matter. These it is obviously not the province of such a work as this to treat in detail. CHAPTER XVII.