19 JUNE 1897, Page 11

LORD ARMSTRONG'S THEORY OF MATTER.

TN the impressive little, or rather both big and little, book (for it is little in its contents and enormously big in its extension in space) which Lord Armstrong has written on "Electric,. Movement in Air and Water, with Theoretical Inferences (published by Messrs. Smith and Elder), one of the most striking of the "theoretical inferences" at which he arrives is that there is no particular reason, so far as he can judge, for considering matter as anything but motion, motion with- out anything to be moved. He quotes Lord Kelvin's saying that "it is scarcely possible to help anticipating the arrival of a complete theory of matter in which all its properties will be seen to be merely attributes of motion," but though Lord Kelvin thought that matter may one day be shown to be that which has no properties except those which are attributes of motion, Lord Kelvin never seems to have suggested that matter may simply be motion,—in other words, interactions of different motions,—which would be another way of saying that there may be motion without anything to be moved. But this is what Lord Armstrong appears to think perfectly conceivable.. For in commenting on Lord Kelvin's phrase, "attributes of motion," he asks "motion of what? "and supposes that the reply must be the ether which is assumed to fill all space and whose undulations radiate light and heat and electricity,—though this ether itself is a mere hypothesis which Lord Armstrong, at least, does not regard as either necessary or useful; since he. says that this hypothetical ether is invented only to supply the subject of the motions which explain the laws of light and heat and electricity, and that for anything he sees, empty space would do just as well as ether, if we only chose to conceive "a continuity of interacting motions" penetrating- all space. "We are more familiar," he tells us, "with motion than with ether, and we do not seem to gain much by postulating two inscrutables instead of one." He thinks that if we chose to "endow space with the attributes assigned to, ether," "the difference vanishes." Motion would thus stand, forth as the " absolute " of "matter." Now we cannot in the least understand what motion, without anything to be moved,. can mean. Motion is the change of a relation. If I go, nearer to some other man, I alter my relation both to himb and to all others. Suppose that I halve my distance from him,. then I may double my distance from some one else, and must change my distance from all other persons and things in an in- definite number of different degrees. And with these changes. of distance, I must change also in the same indefinite variety of ways the attractive force which I exert upon them and they upon me. And doubtless as a consequence of all these changes there will be an indefinite number of other changes in my relation to other beings and other objects in the universe which it would be quite impossible to enumerate or even to imagine. But all of these changes would be changes of relation, and without beings or objects to which I could change my relation, the motions on which Lord Armstrong insists as the absolute essence of matter, would not be intelligible at all. If there were no objects to which my relation was changed, and if I myself were not an object to which the relation of other objects was changed, how could I describe the absolute" of matter as some kind of motion or series of interacting motions P We can understand motion only if we know the relations which motion affects and alters. But relations without related objects are surely quite inconceivable. If I am twice as near to another object as I was, or twice as far from another object as I was, I understand what the motion means, for I understand how it has affected the relation between me and those other objects; but if there are no objects whose relation to each other has been changed by the motion, or series of motions, then surely the motion, which is only a change of relations, or a series of changes of relations, is more than " inscrutable,"—it is unmeaning. We understand Lord Armstrong to say that what we call matter is nothing but motion or an inter- action of various motions; but in that case things, objects, persons, are all made up of motions, and motion being a change of relations, is unmeaning unless we know what the relations are which are changeable and changed. Lord Armstrong thinks that nothing is gained by substituting two " inscrutables " for one "inscrutable," yet surely two inscrutables are often far more intelligible, less inscrutable, than one inscrutable, because the two inscrutables are so coupled together that the one, taken alone, is inconceivable, while the two taken together, are not so. Thus to us, in the world in which we live, both matter is inscrutable and mind is also inscrutable, but matter with mind is less inscrutable than matter without mind ; and the world being what it is, mind with matter is less inscrutable than mind without matter, because we have been so created that the only clues which we have to "mind" are all obtained through the organisa- tion of the body. Again, what shall we say of the three " in- acrutables," "infinity," "naught," and a "negative infinity ? " None of them are really comprehensible by the human mind, except as the limits towards which constant increase, constant decrease, and constant increase of an opposite kind of value,— for example, constant increase of property, constant loss of property, and then constant increase of debt,—tend ; yet they are far less inscrutable taken together than they are taken separately. We all suppose that we understand, "infinity" as the as plus ultra of accumulation, and " nothing " as as plus ultra of subtraction, and again minus infinity as the ?le plus ultra of indebtedness, yet the three taken with- out relation to each other are far more completely beyond the grasp of the mind than the three regarded in their relation to each other. It is far from true that an inscrutable may not be rendered less inscrutable or more comprehensible if it is taken in connection with other inscrutables in close relation to each other. And we are fatly convinced that motion in relation to an infinite ocean of ether is more intelligible than motion per se. And so it is with motion without any moveable object to be moved. We cannot, indeed, grasp the idea of abstract motion at all ; motion is simply unmeaning without assuming some- thing that is to pass from place to place. Lord Armstrong thinks that the idea of a mere void or empty space would be just as good as an infinite ether to render motion apprehensible to the mind. But that seems to us like Baying that a thing, of which it is the very essence that it is always in the same place, like the lines of latitude and longitude which are neither moved nor moveable, is just as serviceable for the purpose of being moved over a chart, as, for example, a ship which defines its locality by its relation to the chart on which its latitude and longitude are marked. But this is absurd. Space is as immoveable in its very essence as the objects which pass over it are moveable. Indeed, you cannot conceive of motion unless you first have in your mind a conception of a universe of three dimensions, and next of the motion of some object, every situation of which can be mapped in any quarter of that universe, and therefore can be moved from one part of it to any other. It seems to us that Lord Armstrong conceives of the eurface of the sphere as if it could be moved up and down over the sphere of which it is the surface. You might just as well say that latitudes and longitudes, by reference to which locality is defined, are themselves localities to be defined by their position in relation to themselves. Motion cannot be "the absolute of matter" unless matter is inseparable from motion. And not even Lord Armstrong, with all his profound belief in the whirl- winds of motion secreted in matter, would assert that. In all these whirlwinds it would still be impossible to deny that a point might snatch a moment's rest, and might thereby,

and for that instant only, cease to be in motion. Make what you will of any points or group of points, they cannot be mere motions. For a motion itself cannot be set in motion, unless it be first transformed into an object or thing capable of either rest or motion. Bat to treat abstract motion as capable of rest, is as self-contradictory as it is to conceive abstract rest as capable of motion.