The real active and objective existence of this "one universe" is made still more sure and is removed still further from all possibility of "illusion," by the fact that we are forced to regard it as being not only "our" universe but the universe also of those "invisible companions" whose vision half-creates it and half-discovers it, even as our own vision does. It is true that to certain types of mind, for whom the definite recognition of mystery is repugnant, it must seem absurd and ridiculous to be driven to the acknowledgment of a thing's existence, while at the same time we have to confess complete inability to predicate anything at all about the thing except that it exists. It must seem to such minds still more absurd and ridiculous that we should be driven to recognize no less than three aspects of this mysterious "something." But since they are included in the same time and space, and since, consequently, they are intimately connected with one another, it becomes inevitable that we should take the yet further step and regard them as three separate aspects of one and the same mystery. Thus we are once more confronted with the inescapable trinitarian nature of the system of things; and just as we have three ultimate aspects of reality in the monistic truth of "the one time and space," in the pluralistic truth of the innumerable company of living souls and the dualistic truth of the contradictory nature of all existence; so we have three further ultimate aspects of reality, in the incomprehensible "something" which holds all souls together; in the incomprehensible "something" out of which all souls create the universe; and in the incomprehensible "something" which forms the substratum both of the souls of the invisible "companions of men" and of the soul of every individual thing. The supreme unity, therefore, in this complicated world, thus revealed to us by the activity of the complex vision is the unity of time and space. This unity is eternally reborn and eternally re-discovered every time any living personality contemplates the system of things. And since "the sons of the universe" must be regarded as continually contemplating the system of things, struggling with it, moulding it, and changing it, according to their pre-existent ideal, we are compelled to assume that time and space are eternal aspects of reality and that their eternal necessity gives the system of things its supreme unity. No isolated speculation of the logical reason, functioning apart from the other attributes of the complex vision, can undermine this supreme unity of time and space. The "a priori unity of apperception" is an unreality compared with this reality. The all-embracing cosmic "monad," contemplating itself as its eternal object, is an unreality compared with this reality.