completely triumphs; but then the One becomes a mystery, or the many survive, and then where are the links?
Two features, frequent, but by no means universal, in realistic systems, I have in this whole summary deliberately kept in the background. Reality has often been regarded, by the realists who are of a more or less Eleatic type, as implying, essentially, the permanence and unchangeableness of the reals. So it was with Plato’s Ideas; so it was with Herbart’s Reals; and Spinoza’s Substance was eternal. A similar eternity the Sânkhya knew, although that doctrine also recognized a realm of real changes. Reality has also often been made, by these or by other Realists, to imply essentially the causal efficacy, the active potency, of the real entities. These two views, of course, cannot easily be harmonized. But regarding both these features of many realistic systems, I can here only observe that they are, to my mind, secondary features.
Historically, they are indeed not unimportant in the development of Realism. Permanence, in the first place, has always been regarded, — and especially by the older forms of Realism, — as a peculiarly strong evidence of independence; and often it has been conceived as, in the second place, a necessary condition of such independence. So it was, for instance, for Herbart. What lasts forever, wholly unchanged by anything, must of course be unchanged by the coming and going of knowledge. Hence the concept of the real as the absolutely Abiding, has played a great part, not only in the Eleatic doctrine, in Plato, and in Atomism, but also in modern, scientifically colored, specu-
