1950J. D. MacDonaldShadow on Sand in Thrilling Wonder Stories Oct. 27/1
We have made the basic and very important discovery of a twin planetary system corresponding to our own, separated from us only by a symbolic logician’s definition of reality. This is not a completely physical and technical phenomenon. It is a philosophical phenomenon. In simplest terms the formula can be expressed this way: The twin world exists because any definitive explanation of reality presupposes alternate realities. Thus the doorway was achieved by the creation of unreality. Call it negative matter if you will. A sphere where there is no reality must, through the application of the basic formula, be a bridge between realities.