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 cannot 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 cannot 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 cannot 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 cannot 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 volumea 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 mediæ. val 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 so we shall only succeed in landing ourselves 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 cannot indeed move itself; but this is true for the same reason that it cannot 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 (Philosophie Positive, Vol. i. p. 550),

'present to our observation no other property than weight, that would suftice 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 towards the centre 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 to-day. 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 things. 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, has seemed, 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 bedistinguished from absolute rest.

Mr. Stallo has expended much ingenuity in combating the views of those who, to use his expression, reify space, and who devote all the powers of mathematical analysis to determining the several modes in which space can exist. The whole structure of socalled transcendental geometry he regards as purely illusory. Instead of crediting space with a fourth dimension, he does not allow it so much as one. Dimensions are properties of bodies, and if we seem able, mentally, to apply measurements to space, it is because the mind has acquired, by long practice, the power of thinking of the dimensions of bodies without taking into account their solidity. Our author explains the matter well : 'Space is a concept, a product of abstraction. All objects of our sensible experience present the feature of extension in conjunction with a number of different and variable qualities attested by sensation; and, when we have successively abstracted these various sensations, we finally arrive at the abstract or concept of a form of spatial extension.' A similar explanation is given in the Philosophie Positive (Vol. i., p. 353), where the conception of space is spoken of as resulting from one of the earliest efforts at abstraction made by the human mind; its formation having, in all probability, been greatly facilitated by the fact that the impress of any material object affords the same means of reason

ing about its size and figure as the object itself.

In Chapter xv. Mr. Stallo touches upon the discussion as to the finitude or infinitude of the material universe, and shows its unreal character. 'We cannot,' he says, 'deal with the Infinite as with a physically real thing, because definite physical reality is coextensive with action and reaction; and physical laws cannot be applied to it, because they are determinations of the modes of interaction between distinct finite bodies. The universe, so called, is not a distinct body, and there are no bodies without it with which it could interact.' The following is also well put, and would have been warmly applauded by the author of the Positive Philosophy :-"The only question to which a series or group of phenomena gives legitimate rise relates to their filiation and interdependence; and the attempt to transcend the limits of this filiation and interdependenceto determine the conditions of the emergence of physical phenomena beyond the bounds of space and the limits of time-are as futile (to use the happy simile of Sir William Hamilton) as the attempt of the eagle to outsoar the atmosphere in which he floats.' We have in the same chapter an interesting discussion and criticism of the Nebular Hypothesis considered as a cosmological theory. As applied to the solar system, Mr. Stallo is not disposed to question the scientific legitimacy of the hypothesis, though he calls attention forcibly to the difficulties by which it is embarrassed. As applied to the universe at large, it becomes unmeaning.

In his concluding chapter, Mr. Stallo tells us that while the atomomechanical theory cannot be, if his reasonings are correct, the true basis of modern physics, he is far from denying the, at least partial, usefulness of the theory considered as an aid to investigation. The steps to scientific, as well as to other knowledge,' he observes, 'consist in a series of logi

cal fictions which are as legitimate as they are indispensable in the operations of thought, but whose relations to the phenomena whereof they are the partial, and not unfrequently merely symbolical, representations, must never be lost sight of.' In this way the circumference of a circle may be considered as made up of an infinite number of straight lines; and this hypothesis will serve for the determination of the area of the circle; while at the same time we know that the circumference and the diameter are radically incommensurable. In like manner the astronomer, no matter what bodies he may be dealing with, always considers the action of gravity as taking place between two mathematical points. The chemist in like manner, when dealing with chemical equivalents, is under no necessity of supposing that the formulas which experience has taught him to use, point to the absolute existence of atoms of varying weights. Enough for him that he has formulas which truly express the facts that take place under his eyes. To quote our author again :

That no valid inference respecting the real constitution of bodies and the true nature of physical action can be drawn from the forms in which it is found necessary or convenient to represent or to conceive them, is illustrated by the fact that we habitually resort, not only in ordinary thought and speech, but also for purposes of scientific discussion, to modes of representing natural phenomena which are founded upon hypotheses long since. discarded as untenable.'

If now we were asked to state in a few words the drift and purpose ofthe interesting and really able work which we have been passing in rapid review, we should say that Mr. Stallo has made, towards the close of the nineteenth century, a remarkable attempt to do what Auguste Comte so strenuously endeavoured to do towards the beginning of the century, viz., to per

suade the scientific world that true science lies only in the region of the relative, that the search for causes is futile, that our knowledge can only be of laws, and that laws when grasped must be regarded as working hypotheses and not as affording any insight into the essential nature of things. Mr. Stallo aims at banishing metaphysics from science; such was also the passionate desire of Comte, a desire so frequently expressed as to give rise to Prof. Huxley's sarcasm that with Comte the word 'metaphysical' was simply a general term of abuse. No man, however, ever knew better what he meant by a word than Comte knew the sense he attached to the term in question; nor did any man ever use one term more consistently in the same sense. One or two out of the numberless passages in which Comte records his opposition to, and distrust of, metaphysics may perhaps be quoted. 'The fundamental character of metaphysical conceptions is to regard phenomena independently of the bodies which manifest them, to attribute to the properties of each substance an existence distinct from that of the substance itself. Once do this, and what does it matter whether you make of these personified abstractions controlling spirits or simply fluids? The origin is the same in either case, and is found in that habit of enquiring into the intimate (absolute) nature of things which characterizes the infancy of the human mind' (Phil. Pos. ii., p. 446). Again: 'Science being wholly unable to ascertain the first causes, or the mode of production of phenomena should concern itself solely with the effective laws of the observed phenomena; and every hypothesis which aims at anything else is, by that very fact, stamped as radically contrary to the true scientific spirit' (Phil. Pos. ii., p. 452). We do not think Mr. Stallo, though coming more than half a century later, has said anything better than this. And remember these are not obiter dicta ;

the whole stress and strain of the Positive Philosophy is in the same direction. Comte desired that science should abide in its lot-the relative -in order that it might become truly positive, that is affirmative and constructive, and that human thought might be spared the wanderings, and human society the confusion, which he saw to be inseparable from a science vitiated by metaphysics; in other words, by pretentious enquiries be. yond its proper range-enquiries to which a character of reality could by no possibility be given. By his attitude towards such enquiries, which greatly strike the popular imagination, and bring much more glory to those engaged in them than merely accurate determinations of law, he incurred the hatred of the majority of scientific men of his day, a hatred which has not infrequent echoes even in our own time. Yet that the path which he indicated is the true path is to the best thinkers becoming daily more evident. We look to Mr. Stallo's work to help forward the demonstration. The question at issue is not one of merely technical interest; it is one of the widest and profoundest interest. 'The reaction,' (of fundamentally erroneous scientific views) says Mr. Stallo in his preface, 'upon the character and tendencies of modern thought becomes more apparent from day to day. The utter

anarchy which notoriously prevails in the discussion of ultimate scientific questions, so called, indicates that a determination of the proper attitude of scientific enquiry toward its objects is the most pressing intellectual need of our time, as it is an indispensable prerequisite of real intellectual progress at all times.' The wars and fightings in the intellectual realm come from the lust of forbidden, or rather impossible, knowledge, not from the difficulties of legitimate research. The evil is a moral, even more than an intellectual, one. Positive science is