In a diagram like the accompanying _b_ and β are, he argues, “mediately conjoined,” but _a_ and α are “immediately co-adjacent.” Surely Dr. Stout forgets here that what can be intelligibly called “co-adjacent” are not lines but points or positions on the lines. And between any point in α and any point in _a_ there are a plurality of intermediate positions, except for the special case of the extreme left point of _a_ and the extreme right point of α. These, of course, coalesce in the single point M, and there is therefore no connection, mediate or immediate, left in this case.[99] The illustration, I think, may serve to reveal a serious discrepancy in Dr. Stout’s theory. He sees that relations presuppose a unity which is supra-relational, and which he calls “continuous,” on the ground of its supra-relational character. At the same time, to save the relational scheme from condemnation as leading to the endless regress, he has to turn this supra-relational unity itself into a sort of relation by calling it an immediate connection between _adjacent_ terms, and thus ascribing to it the fundamental character of a _discontinuous_ series. And I cannot help regarding this procedure as unconscious evidence to the truth of the principle, that what is not the truth about the whole of Reality is not ultimately the truth about any reality. ----- Footnote 73: See the admirable account of the “natural conception” of the world in the final chapter of Avenarius, _Der Menschliche Weltbegriff_. Footnote 74: May I say here once for all, that when I oppose _practice_ to intellectual speculation, I must be understood to mean by practice the alteration by myself of some datum of given existence. The activity of thought is thus for me not practical, precisely because the “truths” which I know or contemplate are not _quà_ truths given existences operated upon and altered by the act of thinking. Footnote 75: Such a view of the mental life of the animal seems to have been actually held, for instance, by the late Professor T. H. Green. Yet see Green, Works, ii. 217. Footnote 76: Strictly speaking, the “solidity” or “impenetrability” of the ultimate particles of matter, which is with Locke and Newton one of the most prominent “primary” qualities, is not a “mathematical” property, but it still owes its inclusion in the list to the conviction of these philosophers that it is, like extension and form, fundamentally important for mathematical Physics. The explanation of the “secondary” qualities as _subjective_ appears to go back to Democritus. Footnote 77: See the further elaboration of this analogy in Bk. III. chap. 3, § 2 ff. Footnote 78: