# Popular Science Monthly/Volume 21/May 1882/Stallo's Concepts of Modern Physics

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* STALLO'S "CONCEPTS OF MODERN PHYSICS."
By W. D. LE SUEUR.
"IT is generally agreed," says Mr. Stallo, "that thought in its most comprehensive sense is the establishment or recognition of relations between phenomena." All perception is of difference; and two ​objects, therefore, are the smallest number requisite to constitute consciousness. On the other hand, objects are conceived as identical by an attention to their points of agreement; though conception may also be regarded as perception applied to a group of objects, so as to bring before the mind its class characteristics; the word well expressing the gathering into one of the several qualities or properties by which the group is distinguished from other groups. Conception is, therefore, the source of ideas, and the word concept expresses the union effected in the mind of those attributes or properties under which a given object is at any moment recognized. In other words, it is "the complement of properties characteristic of a particular class." If the class be a very special one the concept will apply to but few individuals; but the complement of properties which it will connote will be a very comprehensive one. If, on the other hand, the class be a very wide or general one, the concept will apply to a much larger number of individuals, but it will comprehend fewer attributes or properties. As application widens, meaning narrows; until from an infima species, or in English a group of the most special kind, we rise to a summum genus, or a class in which only such properties remain as are absolutely essential to thought. The process by which this is done is the process of abstraction, which consists in dismissing from consideration all properties not essential to the particular class which we may wish to form. Objects are known, it is further to be remarked, "only through their relations to other objects," and each individual object only "as a complex of such relations." No operation of thought, however, "involves the entire complement of the known or knowable properties (or relations) of a given object. In mechanics a body is considered simply as a mass of determinate weight or volume, without reference to its other physical or chemical properties"; and, in like manner, every other department of knowledge only takes account of that aspect of the object which it is necessary for the purpose in hand to study. The mind can not completely represent to itself at any one time all the properties or relations of an object; nor is it necessary that it should do so, as they can not possibly all be relevant to the same intellectual operation. Our thoughts of things are thus symbolical, because what is present to the mind at a given moment is not the object in the totality of its relations, but a symbol framed for the occasion, and embracing just those relations under which the object is to be considered. A concept in which all the relations of an object should be embraced is an obvious impossibility. We can not stand all round a thing all at once; we must choose our side, or, in other words, fix upon our point of view.
The above line of thought will be familiar to all students of philosophy, and particularly to those acquainted with the writings of Mr. Herbert Spencer. For some reason or other, however, Mr. Stallo abstains, not only here but generally throughout his book, from any ​mention of the relation of his philosophical views to those of other writers. He does not give us his bearings, so to speak, but leaves us to discover them for ourselves. We can not think this policy a good one. To the general reader it is not helpful, as it may lead him to form an exaggerated idea of the originality of the views contained in the volume—a result, we are sure, at which the author would not consciously aim. Some special illustrations of what we are now remarking upon may present themselves before we close.
"All metaphysical or ontological speculation is based upon a disregard of some or all of the truths above set forth. Metaphysical thinking is an attempt to deduce the true nature of things from our concepts of them." The last sentence presents us with a definition of admirable terseness and force, stating as it does the whole case against metaphysics in a dozen words. For purposes of thought we analyze and abstract; but, not content with deriving from these operations the logical aid they are calculated to afford, we fly off to the conclusion that what we have done in the realm of thought holds good outside of thought or absolutely. To apply this to the matter in hand: where the "mechanical theory of the universe" asserts mass and motion to be the "absolutely real and indestructible elements of all physical existence," it overlooks the fact that mass and motion by themselves are really elements of nothing but thought, and are simply a kind of mental residuum after all the more special properties of objects have, by successively wider generalizations (as before explained), been mentally abstracted. As our author puts it: "They are ultimate products of generalization, the intellectual vanishing-points of the lines of abstraction which proceed from the infimæ species of sensible experience. Matter is the summum genus of the classification of bodies on the basis of their physical and chemical properties. Of this concept, matter, mass and motion are the inseparable constituents. The mechanical theory, therefore, takes not only the ideal concept matter, but its two inseparable constituent attributes, and assumes each of them to be a distinct and real entity." Mr. Stallo sees in this a survival of mediæval realism; but it is really nothing else than the opinion of the multitude, now and in all ages, elevated to the rank of a philosophical doctrine. Men in general are materialists who temper their materialism to themselves by a supplementary belief in spiritual existences.
Not only is the mind prone to believe that its concepts are truly representative of external realities, but it readily assumes also that the order of succession in the world of thought must be the order of development in the external world. The effect of the latter illusion is completely to invert the order of reality. "The summa genera of abstraction—the highest concepts—are deemed the most, and the data of sensible experience the least, real of all forms of existence." Because we arrive at the concept matter by leaving out of consideration all the properties that differentiate one form of matter from another, ​and because matter thus divested of its special properties forms a kind of rock-bed of thought, we conclude that similarly undifferentiated matter must form the rock-bed, or, to vary the figure, the original raw material, of the objective universe. But manifestly, in the scale of reality, the highest place must be given to things as they are, to individual objects with their full complement of properties, and successively lower places to such objects robbed by abstraction of one after another of their essential attributes. When we come to matter, we have just enough left to think about and no more. The logical faculty, however, goes further, and performs the tremendous feat of sundering the elements, mass and force, the conjunction of which alone renders matter a possible object of thought; whence arise endless discussions as to whether motion is a function of matter, or matter a function of motion. The first opinion is known as the mechanical or corpuscular theory of matter, and the latter as the dynamical. The true answer to these intellectual puzzles is that we have no business dealing with the mere elements of thought as if they were elements of things, and that so long as we do we shall only succeed in landing ourselves in in what Mr. Spencer calls "alternative impossibilities of thought."
The notion of the inertia of matter is similarly a product of abstraction, and by no means a representation of fact. Our author's explanation (page 163) is as follows: When a body is considered by itself—conceptually detached from the relations which give rise to its attributes—it is, indeed, inert, and all its action comes from without. But this isolated instance of a body is a pure fiction of the intellect. Bodies exist solely in virtue of their relations; their reality lies in their mutual action. Inert matter, in the sense of the mechanical theory, is as unknown to experience as it is inconceivable in thought. Every particle of matter of which we have any knowledge attracts every other particle in conformity with the laws of gravitation; and every material element exerts chemical, electrical, and other force upon other elements which, in respect of such force, are its correlates. A body can not, indeed, move itself; but this is true for the same reason that it can not exist in and by itself. The very presence of a body in space and time, as well as its motion, implies interaction with other bodies, and therefore, actio in distans; consequently, all attempts to reduce gravitation or chemical action to mere impact are aimless and absurd.
This whole passage is so completely on the lines of the Positive Philosophy, that to us it seems singular that the author could have penned it without making some reference to the precisely similar views of Auguste Comte, views which the scientific world in general has largely disregarded or ignored. "Did the material molecules," says Comte ("Philosophic Positive," vol. i, p. 550), "present to our observation no other property than weight, that would suffice to prevent any physicist from regarding them as essentially passive. It ​would be of no avail to argue that, even in the possession of weight, they were entirely passive, inasmuch as they simply yielded to the attraction of the globe. Were this correct, the difficulty would only be shifted; the earth as a whole would then be credited with an activity denied to separated portions of it. It is, however, evident that, in its fall toward the center of the earth, the falling body is just as active as the earth itself, since it is proved that each molecule of the body in question attracts an equivalent portion of the earth quite as much as it is itself attracted, though, owing to the enormous preponderance of the earth's attraction, its action alone is perceptible. Finally, in regard to a host of other phenomena of equal universality, thermal, electric, and chemical, matter plainly presents a very varied spontaneous activity of which it is impossible for us henceforth to regard it as destitute. . . . It is beyond all question that the purely passive state in which bodies are conceived to be when studied from the point of view of abstract mechanics becomes under the physical point of view a complete absurdity." Nearly sixty years have elapsed since this was written; and yet, as Mr. Stallo's book proves, there is a necessity for repeating and re-enforcing it today. The same may be said of the doctrine that all our knowledge of objective reality depends upon the establishment and recognition of relations; or, in other words, that the properties of things by which we know them are their relations to other thing This doctrine lies at the very foundation, not only of the Positive Philosophy, but of all true philosophy, and yet, according to the statement of our author, it has been almost wholly ignored by men of science, as well as by metaphysicians, who constantly put forward the view that whatever is real must exist absolutely"; or, in other words, that nothing which does not exist absolutely can be real. Hence have arisen the endless discussions as to absolute motion and rest. That motion could be real, and yet only relative, L rued, even to such eminent thinkers as Newton, Leibnitz, and Descartes, wholly impossible; yet far from there being any impossibility in the matter, the truth is that it is only relative motion that can have to our apprehension the character of reality. Absolute motion could in no way be distinguished from absolute rest.