Page:The World and the Individual, First Series (1899).djvu/258

Rh in this respect followed his footsteps. Mr. Spencer’s Unknowable is, on the whole, a realistic conception, although sometimes spoken of in mystical terms. But Mr. Spencer’s world of the Knowable has a reality of the Kantian type. It is a world of valid empirical truth. John Stuart Mill elaborated our Third Conception in his famous chapter on the “Psychological Theory of Our Belief in an External World,” in his Review of Sir William Hamilton’s Philosophy. His definition of matter as a permanent possibility of sensation is altogether of our present type. Several of the writers most prominent in the recent logical movement have used what is essentially this view of the nature of scientific truth. So, notably, Wundt, in his discussions of the fundamental ideas of the physical sciences, for example, the ideas of Substance and of Cause. In a very different spirit, Avenarius, while rejecting absolute validity, reaches a view of the real which is much of our present sort.

The conception now in question, as you see, is indeed technical in its character; but it has so many bonds of connection with popular thinking and with exact science, that, when once defined, as our century has learned to define it, it is sure to have a great practical potency in affairs. In earlier lectures I called the typical realists the partisans of strict conservatism, the philosophical defenders of the extreme Right of any social order.