moves; that between a given position as revealed by vision, and the amount of bodily movement required to reach it. All such necessities of thought corresponding to necessary external relations, are accompaniments of reflex discharges through nervous structures so perfectly organized by ancestral and individual experiences, that the channels they open are inevitably taken by the discharges initiated.

Most striking and instructive, however, is the correspondence existing between these facts of nervous structure and function, and the interpretation which was given of our consciousness of space. Grant that what we know psychically as an association of ideas, answers physically to a discharge between two excited nervous elements-grant that the strengthening of this association by repetition, corresponds to the making of the channel for this discharge more permeable -grant that the effect of habit in changing a voluntary conscious act into an act more and more automatic, answers to the formation of a more perfect nervous connexiongrant that the reflex actions thus gradually established in that part of the nervous system devoted to mental functions, are of the same nature as the reflex actions in that part of it by which bodily functions are carried on; and we may see how there has been evolved, and is from moment to moment reproduced, that consolidated conception of space which seems so marvellous. For, in the first place, the visual consciousness of any one point to which the eyes are converged, is automatically connected by infinite repetitions in the individual and his progenitors, with the consciousness accompanying those nervous acts by which the axes and foci of the eyes are adjusted to that point, and, also, when near, with the consciousness of those movements by which the point can be reached; and, in the second place, infinite repetitions have simultaneously established connexions be tween the nervous adjustments which go along with the consciousness of that point, and the nervous adjustments made in passing through each point on the way to it; so

that with the reflex consciousness of the motion required to be gone through in reaching a position on which the eyes are converged, there goes a reflex consciousness of all the intermediate positions. Further, in universal experience, each object looked at, occupying a cluster of positions more or less extensive, has, while exciting the most vivid consciousness of that particular point in it on which the visual axes are converged, also partially excited those nervous agents corresponding to all the other positions it occupies. Whence it has come to happen, that when these other positions are not occupied, yet, by reflex excitement, a distinct consciousness of any one position arouses a multitude of consciousnesses of the positions which constitute surrounding space. In brief, the laws of nervous organization warrant the inference that there has been evolved, by converse with adjacent space and the objects it contains, an extensive and elaborate plexus, the multitudinous parts of which correspond to the multitudinous positions in adjacent space; and which, in virtue of its extreme definiteness of organization, cannot have one of its parts excited without a reflex excitement of all the rest being produced, so as to generate a simultaneous consciousness of all the positions to which they answer. As harmonizing with this view, three traits of this consciousness may be named. The first is that the consciousness of the space close to us is far more intimate and detailed than the consciousness of remote space; which would obviously result from this reflex excite. ment through organic connexions established in experience. The second is that when the eyes are turned in any direction, the space-consciousness is much more minute and complete immediately around that direction than on the outskirts of the field of vision-a fact similarly explicable. And the third is that in the dark, especially when the place is unknown, the ordinary consciousness of space almost disappears, leaving only that part of the consciousness which accompanies freedom to move; while in a known place, as a

familiar room, such consciousness of space as remains, accompanies an ideal representation of the objects it contains. Let me add that, while we are thus enabled to understand how the space-consciousness is constituted, we are also furnished with an explanation of such special intuitions as the geometrical axioms; since these are interpretable as indissoluble connexions in consciousness, corresponding to certain reflex actions which occur in the space-plexus when certain. data are presented.

Not only, then, do we find entire congruity between the special results synthetically reached and those reached by analysis, but wo find that each elucidates the other.

CHAPTER V.

CO-ORDINATION OF GENERAL ANALYSES

§ 475i. The inquiries carried on in the divisions & bstracted and compared in the foregoing four chapters, assumed the co-existence and co-operation of subject and object. Avowedly made as provisional at the outset of First Principles, and there justified only by a brief survey of the reasons for making it, this assumption was, in Part VII. of this work, returned to for the purpose of finally justifying it. Reverting to the inference originally reached, that justification for this ultimate dictum of consciousness must consist in proof of its congruity with all other dicta, we proceeded to set forth the proof.

The general argument was composed of three portions. The first, dealing with the assumption of metaphysicians, their words, and their reasonings, made it clear that, to whatever school they belong, metaphysicians invariably and inevitably connote, alike by their terms and their arguments, the existence of a non-ego independent of the ego; and that thus, while congruity emerges with a realistic conclusion, an absolute and fatal incongruity is involved by any other conclusion. Dealing with the question more specially, the next group of chapters compared the arguments for and against realism in respect to their priority, their simplicity, and their distinctness; with the result of showing that the realistic belief, first in order of genesis, is that on which the

idealistic argument stands; that the mental process yielding the realistic belief is relatively brief and simple, and less liable to be vitiated by error than the long and involved process supposed to yield the idealistic belief; and that while the states of consciousness which, as combined, yield the one belief, are of that vivid kind in which most confidence is to be placed, the states of consciousness which yield, or are supposed to yield, the other belief, are of that faint kind in which less confidence is to be placed. And the implication was that while the realistic belief withstands the usual tests of certitude, the opposed belief is triply discredited by them.

After thus broadly distinguishing these antagonist doctrines as the one consistent with itself and with all results otherwise reached, and the other as inconsistent with both, we proceeded to judge between them more definitely by means of a criterion which must be accepted in common by their respective defenders. Having explained that before they can be rightly compared, propositions must be analyzed and reduced to like degrees of simplicity, it was shown that our ultimate ground for accepting a proposition as unquestionably true, is the inability to conceive the negation of it. And having recognized the fact that for every step in an argument this is the ultimate justification, we saw that by no possibility can this test be invalidated; since every step in any argument constituting the supposed invalidation, must assume the test. Hence, as Idealism and Realism both proceed upon the Universal Postulate, the realistic conclusion which, being reached by a single direct act of consciousness, invokes it only once, is of high validity in comparison with the idealistic conclusion, which, reached by many steps and invoking it at every step, is proportionately liable to error from mental lapsus.

Such being the negative justification of Realism implied by the logical inferiority of the idealistic argument, we proceeded to that positive justification of it furnished by