TIME AS RELATED TO CAUSALITY AND TO SPACE. 217 Yet however he denies its ultimateness, however strenuously he claims the existence of a deeper unity, monist as well as pluralist acknowledges the subordinate categories of pheno- menal reality, that is the unifications of the superficial facts of experience. Of these forms of what is at least phenomenal unity, two may be clearly distinguished : identity, that is the unity of the ' thing ' or ' quality ' with itself, in spite of the multi- plicity of its temporal moments ; and necessary connexion or the unity of the many with each other, that is, the relation, direct or indirect, of every bit of reality with every other, just by virtue of their both forming part of the same world. Such a reduction of the principles of phenomenal unity is suggested to the careful student by an elimination of categories from Kant's elaborate table : for the categories of Quality turn out to be attributes of sense elements, and not in any true sense functions of unity ; those of Quantity prove their practical identity with time and space ; and the categories of Modality are admitted by Kant himself to stand on quite another footing from the others being virtually, indeed, mere varying expressions of his insistence upon the greater reality of the sensuous. The true functions of unity are evidently, then, to be sought under the head of ' Relation ' ; and there, we find, Kant recognises substance or permanence (a modification of identity), Causality or the necessary con- nexion of the Successive, and Reciprocal Determination, or the necessary connexions of the simultaneous. So Schopen- hauer, whose metaphysical doctrine has failed, unhappily, of its rightful influence, because overshadowed by his ethical system, Schopenhauer, though he overlooks permanence and identity, reduces the categories to one, that of necessary connexion, or, as he names it, Grund, of which time, space and causality are subordinate forms. " Alle unsere Vor- stellungen," he says, " stehen unter einander in einer gesetzmassigen Verbindung, vermoge welcher nichts fur sich Bestehendes und Unabhangiges, auch nichts Einzelnes und Abgerissenes Objekt fur uns werden kann. Diese Verbindung ist es, welche der Satz vom Zureichenden Grunde ausdriickt." 1 To discuss both sorts of phenomenal unity would lead us too far afield. We are more concerned with this last named, so clearly described by Schopenhauer ; the necessary relation of all the diverse facts of the universe to each other, a principle of unity manifested in many ways, by the com- 1 Vierfache Wurzel des Satzes vom Zureichenden Grunde, 16.
