All the more probable does the latter hypothesis become when we take into consideration the frequent tricks played by sportive denizens of the other world, against which the untrained person is usually absolutely defenceless. It must also be remembered that the regular inhabitant of the astral plane, whether he be human or elemental, is under ordinary circumstances conscious only of the objects of that plane, physical matter being to him as entirely invisible as is astral matter to the majority of mankind. Since, as before remarked, every physical object has its astral counterpart, which _would_ be visible to him, it may be thought that the distinction is a trivial one, yet it is an essential part of the symmetrical conception of the subject. If, however, an astral entity constantly works through a medium, these finer astral senses may gradually be so coarsened as to become insensible to the higher grades of matter on their own plane, and to include in their purview the physical world as we see it instead; but only the trained visitor from this life, who is fully conscious on both planes, can depend upon seeing both clearly and simultaneously. Be it understood, then, that the complexity exists, and that only when it is fully perceived and scientifically unravelled is there perfect security against deception or mistake. For the seventh or lowest subdivision of the astral plane also this physical world of ours may be said to be the background, though what is seen is only a distorted and partial view of it, since all that is light and good and beautiful seems invisible. It was thus described four thousand years ago in the Egyptian papyrus of the Scribe Ani: "What manner of place is this unto which I have come? It hath no water, it hath no air; it is deep, unfathomable; it is black as the blackest night, and men wander helplessly about therein; in it a man may not live in quietness of heart." For the unfortunate entity on that level it is indeed true that "all the earth is full of darkness and cruel habitations," but it is darkness which radiates from within himself and causes his existence to be passed in a perpetual night of evil and horror--a very real hell, though, like all other hells, entirely of man's own creation. Most students find the investigation of this section an extremely unpleasant task, for there appears to be a sense of density and gross materiality about it which is indescribably loathsome to the liberated astral body, causing it the sense of pushing its way through some black, viscous fluid, while the inhabitants and influences encountered there are also usually exceedingly undesirable.