Consider the two dimensional analogue.
Fig. 7
Suppose that "A" Fig. 7, represents a two-dimensional observer and that X, Y, and Z are two-dimensional closed spaces, rooms, houses, or what not. The interiors of these closed spaces will be invisible to "A." All he will be able to see will be a straight line as at "B," for the boundaries of X, Y, and Z will be opaque and impassable to him.
But now suppose that he were to be lifted up vertically, out of the plane of the paper altogether. He would from this new position be able to see the interiors of X, Y, and Z, together with any two space incidents occurring therein. They would present approximately the appearance shown in Fig. 7 and the degree of foreshortening would diminish with the height to which he ascended above the plane of the paper.
In a precisely analogous manner we must suppose that three-dimensional obstructions do not exist for, and that the interiors of closed three-dimensional spaces are entirely open to, anyone who could regard them from a point situated in four space, i.e., removed from three space to a suitable distance in the direction of the fourth dimension. The greater this distance the less will be the foreshortening and the greater will be the range of vision.
There would be no question of intervening objects obscuring the view, simply because, in four space, three space objects do not intervene—the view of X in Fig. 7 is in no way obscured by the presence of Y or Z.
Compare with this the statements of many clairvoyants to the effect that when in the clairvoyant state they can, and do, see the front, sides, back, and every internal point of three space objects simultaneously.
The parallel is almost irresistible in its significance. Compare also the following case given by Professor de Morgan, and which is typical of the very numerous cases of this nature on record.