alike real, and each is as indispensable as every other to the existence of the whole. In the sense that the whole is more explicitly present in one than in another, there is an infinity of possible degrees of reality and unreality. We should be justified in borrowing a term from mathematical science to mark this double relation of the appearances to their Reality, and speaking of them as successive orders of Reality. And we might then say that it is one of the principal problems of a complete Philosophy to ascertain and arrange in their proper sequence, as far as the limitations of our knowledge permit, the orders of Reality. § 4. Such a task as this could only be carried out by an intelligence equally at home in metaphysical analysis and in the results of the special sciences, and would form the proper work of applied Metaphysics. In a discussion of general metaphysical principles it is sufficient to indicate the general nature of the criteria by which the degree of reality exhibited by any special partial system must be determined. Now, this general nature has been already made fairly clear by the foregoing inquiry into the unity of Reality. Reality, we have seen, is one in the sense of being an individual self-contained whole of experience. And its individuality means that it is the systematic embodiment of a single coherent structure in a plurality of elements or parts, which depend for their whole character upon the fact that they are the embodiment of precisely this structure. If this is so, we may say that degrees of reality mean the same thing as degrees of individuality, and that a thing is real precisely to the same extent to which it is truly individual. A thing, that is, no matter of what kind, is really what it appears to be, just in so far as the thing, as it appears for our knowledge, is itself a self-contained and therefore unique systematic whole. Or, in other words, just in so far as what we recognise as one thing shows itself, in the face of philosophical criticism and analysis, to be a self-contained systematic whole, so far are we truly apprehending that thing as a manifestation of the fundamental character of Reality, of seeing it as it really is, and so far does our knowledge give us genuine Reality. On the other hand, just so far as what at first seemed a self-contained whole is discovered by subsequent analysis not to be so, so far have we failed to see the facts in their true place in the single whole of Reality, and so far is our knowledge affected with error and unreality. Or, again, the more truly anything is a self-contained individual whole, the higher its place in the scale of Reality.