given to us in experience, and therefore, thought of in relation to them. In what, then, consists the difference between figure and size as known to us? Simply in this :-When thinking of a thing's figure, we think of the relations of magnitude which its constituent parts bear to one another; but when thinking of its size, we think of the relation of magnitude which it, as a whole, bears to other wholes. Still there remains the question-What is a magnitude considered analytically? The reply is-It consists of relations of position. When we conceive anything as having a certain bulk, we conceive its opposite limiting surfaces as more or less removed from each other; that is as related in position. When we think of a particular area, we think of a surface having boundary lines standing to one another in specific degrees of remoteness; that is—as related in position. When we imagine a line of definite length, we imagine its termini as occupying places in space having some positive distance from each other; that is as related in position. A solid is decomposable into planes; a plane into lines; lines into points; and as adjacent points cannot be conceived as distinct from each other, without being conceived as having relative positions, it follows that every cognition of magnitude is a cognition of relations of position, which are presented to consciousness as like or unlike other relations of position.

This analysis brings us to the remaining space-attribute of body-Position. Like Magnitude, Position cannot be known absolutely; it can be known only relatively. The position of a thing is inconceivable, save by thinking of that thing as at some distance from one or more other things. Imagine a solitary point A, in space which has no assignable bounds; and suppose it possible for that point to be known by a being having no locality. What can be predicated respecting its place? Absolutely nothing. Imagine another point B, to be added. What can now be predicated respecting the two? Still nothing. Neither point having any

attribute save position, the two are not comparable in themselves; and nothing can be said of their relative position from lack of anything with which to compare it. The distance between them may be either infinite or infinitesimal, according to the measure used; and as, by the hypothesis, there exists no measure-as space contains nothing save these two points, the distance between them is unthinkable. But suppose that a third point C, is added. Immediately it becomes possible to frame a proposition respecting the positions of the three. The two distances A to B, and A to C, serve as measures to each other. The space between A and B may be compared with the space between A and C; and the relation of position in which A stands to B, is thinkable as like or unlike the relation in which A stands to C. Position, then, is not an attribute of body in itself, but only in its connexion with the other contents of the universe.

Relations of position are of two kinds: those which subsist between subject and object; and those which subsist between either different objects, or different parts of the same object. Of these the last are resolvable into the first. On remembering that in the dark a man can discover the relative positions of two objects only by touching first one and then the other, and so inferring their relative positions from his own position towards each; and on remembering that by vision no knowledge of their relative positions can be reached save through a perception of the distance of each from the eye; it becomes clear that ultimately, all relative positions may be decomposed into relative positions of subject and object.

These conclusions-that Figure is resolvable into relative magnitudes; that Magnitude is resolvable into relative positions; and that all relative positions may finally be reduced to positions of subject and object-will be fully confirmed on considering the process by which the space-attributes of body become known to a blind man. He puts out his hand, and touching something, thereby learns its position

with respect to himself. He puts out his other hand, and meeting no resistance above, or on one side of, the position already found, gains some negative knowledge of the thing's magnitude-a knowledge which three or four touches on different sides of it serve to render positive. And then, by moving his hands over its surface, he acquires a notion of its figure. What, then, are the elements out of which, by synthesis, his perceptions of magnitude and figure are framed? He has received nothing but simultaneous and successive touches. Each touch established a relation of position between himself and the point touched. And all he can know respecting magnitude and figure-that is, respecting the relative positions of these points to one another is necessarily known through the relative positions in which they severally stand to himself.

Our perceptions of all the space-attributes of body, being thus decomposable into perceptions of positions like that gained by a single act of touch, we have next to inquire. what is contained in a perception of this kind. Obviously to perceive the position of anything touched, is to perceive the position of that part of the body in which the sensation of touch arises. Whence it follows that our knowledge of the positions of objects, is built upon our knowledge of the positions of our members towards one another-knowledge both of their fixed relations, and of those temporary relations they are placed in by every change of muscular adjustment. That this knowledge is gained by bringing each part in contact with the others and moving the parts over one another in all possible ways; and that the motions as well as the touches involved in these mutual explorations, are known by their reactions upon consciousness; are propositions that scarcely need stating. But it is manifestly impossible to carry the analysis further without analyzing our perception of motion. Relative position and motion are two sides of the same experience. We can neither conceive motion without conceiving relative position, nor dis

cover relative position without motion. For the present, therefore, we must be content with the conclusion that, whether visual or tactual, the perception of every statical attribute of body is resolvable into perceptions of relative position which are gained through motion.

§ 329. Before defining in its totality the perception of body as presenting statical attributes, it is needful to remark that the resisting positions which, as co-ordinated in thought, constitute the consciousness of Magnitude or of Figure, must be aggregated—must be continuous with an assemblage of intermediate resisting positions. If they are discontinuous— if they are separated by positions that do not resist, we have a perception not of the space-attributes of one body, but of the space-attributes of two or more.

Premising this, and omitting as doubly mediate our visual perceptions, we may say that the perception of body as presenting statical attributes, is a composite state of consciousness, having for its primary elements the indefinite impressions of resistance and extension, unconditionally united with each other and with the subject in relations of coincidence in time and adjacency in space; and having for its secondary elements sundry definite impressions of resist ances, variously united with each other in relations of simultaneity and sequence that are severally conditional on the nature of the object and the acts of the subject, and all of them conditionally united with the primary elements by relations of sequence.

To which there is only to add, as before, that these being the materials of the perception, the process of perception consists in the unconscious classing of these impressions, relations, and conditions, with the like before-known ones.

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CHAPTER XIV.

THE PERCEPTION OF SPACE.

§ 330. In the last chapter, much has been tacitly asserted respecting our perception of Space. The consideration of occupied space cannot be dissociated from the consideration of unoccupied space. The two being distinguished as resistant extension and non-resistant extension, it is impossible to treat of either without virtually treating of both. Substantially, therefore, the inquiry on which we are now to enter must be a continuation of the one just concluded. Before commencing it, something must be said in answer to those who, holding with Kant that Space is a form which belongs to the subject and not to the object, consider all attempts to analyze our consciousness of it as absurd.

Among these, is Sir William Hamilton; who says that "it is truly an idle problem to attempt imagining the steps by which we may be supposed to have acquired the notion of extension; when in fact we are unable to imagine to ourselves the possibility of that notion not being always in our possession."

On this proposition the first comment to be made is that a philosopher, dealing with questions of so subtle a kind, becomes a doubtful guide when he hampers the statement of his doctrine by a phrase which seems to mean something but really means nothing; as in the last clause of the passage I have quoted. The entire fact to which Sir W.