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tween things so very different, he imagines, in spite of the import of my words, and of all contextual propriety, that when I am speaking and reasoning about analytical proof, I must mean analytical induction. In confirmation that this was the view which I was then taking of the subject, I may mention, that in order to illustrate my meaning I stated a few things which were necessary towards supplying this analytical proof, such as refuting the prevailing hypothesis of the undulatory nature of light, &c.

We must by no means imagine, because certain principles are fairly the result of an inductive investigation, that the truth of any system founded on them is therefore necessarily established. We may go further, and say, that this consequence does not follow, even if the principles are more than legitimate inductions-even if they are really found to exist in nature, for without being untrue, they may be insufficient to support so extensive a system as may be wished to erect upon them. Other unknown principles of co-ordinate value may really prevail in the natural system, which, after all, may not be quite so simple as in the artificial system, it may be convenient for the grasp of man's intellect to make it. Hence arises the necessity of testing the truth of a system, independent of, and apart from, its principles. If the system be found true, of course the principles cannot be false; but the converse will not follow, that because the principles are true, the system must be true also; for besides the truth of its principles, a true system requires a sufficiency in regard to their number, and an efficiency in regard to their character, by which they may be qualified fitly and adequately to meet the exigencies of all the particular cases. It is not enough to show that the principles do exist among the causes of things, for they may have only a concurring or a partial jurisdiction; it is necessary that they be not fewer than nature herself demands, for under the guise of simplicity in this particular, real complexity and circuitous procedures have been introduced into the working operation of systems, in order to bring the inapposite principles to bear in any manner upon facts. It is necessary also, that they be fully competent to carry all the deductions which are referred to them, for even acknowledged principles are not

to be tortured and twisted to serve purposes to which they are really inapplicable. A system whose principles in their abstract truth are really not to be controverted, may still be very deficient therein, both as to their number and their quality, when they are considered in reference to their fitness for supporting a very extensive superstructure. I might also advert to the mechanism of the operations, or the form or mode in which the principles are brought into action, but this is a topic which I must pass. These things show, that to establish a system as indubitable, we must bring it as a whole to the test of a severe investigation, and to the strict analytical proof of rejection, by showing that the phenomena cannot happen in any other manner. We must have the criterion instances, which Bacon requires for the removal of all doubt on any subject, and which enable us "to decide the question by rejecting all the causes but one." We must prove in regard to the principles of the system, not merely that they are true, but that they alone are sufficient, and that they only are adequate to furnish the explanations of phenomena which are adduced. Am I exacting too hard a task? I did not before, nor do I now invite Mr. Exley to undertake it, knowing very well that in the present state of science it is impossible for him to accomplish it. I merely pointed it out to his attention, as that which, if successfully pursued, could alone justify his extreme confidence in the truth of his system. This task, however, must be undertaken-this proof must be produced before, in reference to this system, be it theory or be it hypothesis, it can be determined whether it belongs to the category of the things that are, or of the things that may be; but Mr. Exley, with the enthusiasm natural to him as the author of it, would forestall the favourable award of posterity. Instead of commencing with first principles of such extreme generality-so fundamental indeed that we presume on knowing the primal essential forces of matter-and thence with à priori reasoning, working downwards to phenomena, we shall do more wisely, at least for the present-at any rate we shall be more succes-ful-if we work upwards with experiments and inductive reasoning, and restrain the imagination or genius from overleaping very many of the intermediates which connect

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the known with the unknown. subordinate flights are admissible and useful, witness Dr. Dalton's, by which he alighted on the doctrine of definite proportions, but Mr. Exley's more ardent and impatient Pegasus, vaults at once to the primal spring and source of things.

Mr. Exley observes-"In the sixth head Mr. C. thinks the distinction of atoms into two widely different classes is not conformable to analogy; my head thinks otherwise." However that may be in regard to Mr. Exley's head, his hand it appears has not been induced by it to write much otherwise, for a few lines further on he says, "I think it probable that the electric fluid, which I have classed with the ethereal, may form an intermediate class, approaching that which constitutes light and caloric."

Mr. Exley in reference to my inquiry, who shall make it an axiom that bodies can only act where they are?—makes answer "common sense.". Nay, not common sense-cultivated sense, or philosophy, if you please, but not common sense, which is continually presenting to us the appearances, at least, of bodies exercising powers where they are not. It is not impossible that it is a gravific fluid and a magnetic fluid, which respectively produce the phenomena of the tides and local attraction: but we must acknowledge that it looks very much like a case of bodies acting where they are not, those bodies being respectively the sun and moon and the magnet; and common sense being satisfied with looking over the surface of things, accepts this explanation of the case. Is

it not, however, the dictate of good sense and sound philosophy that bodies not merely can, but that they necessarily must act where they are not? The place where a body acts is the place where the action is felt. If of two contiguous atoms, one acts upon the other, it must act in the place where the other is, for there the action takes place. To suppose that an atom can only act where it is, is to suppose that the acting atom and the atom acted on occupy the same place. It may be objected that the surface of contact is the place of action. But this is a mathematical surface, and if the atoms are spheres, it is a mathematical point, and these have no place. The action is on one side or the other of the

imaginary point or surface, and is of

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course on the side along with the effect, or rather is itself the effect. It may be objected again, that the axiom in question requires only that the atoms shall be in contact, and that, strictly speaking, it does not mean that bodies can act only exactly where they are. It must mean this, or nothing that is at all essential. Whether two atoms are in contact or not, it has been shown, if they have any magnitude, that action must take place at a distance, and simply because, however near, they cannot occupy the same place. This question of distance is the real and influential point in dispute; and if there be any, it matters nothing whe. ther it be great or little. Besides are all bodies?—are any bodies in contact? These questions would open too wide a field for discussion to be any more than alluded to. Enough has been said, I hope, to show that neither common sense nor philosophical sense answer for the axiom in question; and that it is only worthy to rank as an intuitive truth "in the region of pure intellect," along with many others which the Schoolmen have left us.

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In regard to the subsidiary hypotheses, with which I had stated that Mr. Exley found it necessary to prop up his system, he strenuously contends that he has not introduced any, and founds this denial on the consideration that "he has assumed nothing except what the theory à priori indicates." This may be, but the subsidiary hypothesis is an hypothesis, although the grand hypothesis should indicate the minor one. The question is, whether some subordinate points are not assumed. Mr. Exley himself admits they are, but then he says he was led to them by his theory. What is this but saying, in other words, that the wants of his theory indicated what was necessary to make it hold together, and which he assumed accordingly. If these subordinate points were unavoidable deductions from his principles, he would not speak of them as being indicated by his theory, nor of his having assumed them. Mr. Exley does not venture to affirm that they are necessary conclusions from his theory: wanting that character, there fore, I am fully justified in the statement that I made, and which though he impugns he has unwittingly confirmed its accuracy, namely, "that various subsi diary hypotheses are introduced, for

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which no reason can be adduced but their convenience, and no proof but their fitness to make facts and theory accord." In illustration of it, I instanced his explanation of the difficulty of accounting, why of all the metals, iron, nickel, and cobalt, are capable, in any particular degree, of becoming magnetical, and quoted the passage, which he says he cannot find in his work. He will find it at page 366. It runs thus :-"In some conductors the fluid may be transmitted merely over the surface, in others through the interior substance; but in such as admit of magnetism, in a sensible degree, it must be capable of entering the surface to a very small distance, and by pressing or crowding the atoms of the body in its course together be incapable of making its way in a straight course; and this condition appears to belong to few bodies." Now, what is all this but pure supposition? The ethereal matter it is assumed must be сараble of doing this, and incapable of doing that, and why?-because the fact requires it, and because the prior subsidiary hypothesis of a spiral channelling of magnetic bodies will not hold good without it.

In the parallel passage quoted from his work by himself in page 117 of your Magazine he observes: "Now the magnitude of the spherules and forces of the atoms or particles which compose some conducting bodies may be such, that they shall be susceptible of receiving and retaining the im-. pressions of the above-mentioned current, &c.; and particularly this may be the case with iron and ferruginous bodies." It is quite enough to say that, for aught we can tell, the circumstances may not be such, and the case may not be as is here confessedly supposed; and what can Mr. Exley advance in support of the affirmative, save only and except, that the wants of his theory indicate the convenience of so representing the matter? It would be vain to refer us to the fact, for that may be cited in favour of any other supposition. Even in the case of the true hypothesis it would be reasoning in a circle, for by going back again to the same fact which suggested it, we should obtain no additional evidence. Mr. Exley in effect says-so and so is possible, and therefore it is—at least my theory requires that such it should be; yet in reference to this very case he

says, "no hypothesis is introduced here!" I have been the more inclined to adduce this case in illustration of my observations, from the circumstance that it is at this point philosophers just at the present time are stopped in their electro-magnetic researches. Has Mr. Exley, by the aid of his theory, elucidated the subject in the slightest degree? He has stated how he imagines the fact "may be;" but Ampère's or any other person's "may be," would have the same ground to rest upon. Then there is the subsidiary hypothesis of the mode in which he supposes bodies to be rendered magnetic, namely, by a penetration and a spiral channelling of their substances by an ethereal fluid, and by a constant current in those channels of such ethereal fluid. Now, admitting the existence of the gyrating ethereal currents in the atmosphere, can Mr. Exley prove that the local currents necessarily follow as an effect from such a cause? Does the. conclusion inevitably flow from the premises? Unless he can show that such must be, and not that such may be the case, surely we are entitled to say that this his ingenious supposition, is but a convenient subsidiary hypothesis, in order to eke out or complete the more general one. It is, however, more than problematical, whether this conjecture be as just as it is confessedly ingenious, for I have drawn Mr. Exley's attention to an experiment, which is as I conceive, utterly inconsistent with it; I allude to the fact of a plate of hardened steel being rendered magnetic in very fine lines, by the angular corner of a magnet being drawn over it in any direction. Now if the communication of magnetism takes place, as Mr. Exley contends, by a continuation to the body magnetised of the spiral current which flows around the body of the magnet, such communicated influence ought to be commensurate with the spiral from which it was propagated. But this is not the case, for the magnetic lines are extremely fine, and correspond with the point in contact, and not with the diameter of the spiral around the magnetic bar. This and other experiments were submitted to Mr. Exley for explanation, which he has obligingly afforded. The powers of his theory, he observes, "explain them off hand." Unfortunately, however, it is this very off-hand,

indistinct manner of giving explanations, which affords so much less satisfaction to the reader than it does to the author. Surely the specimens which he has given are cases in point. For instance, in regard to the experiment of magnetic communication just stated, he merely observes, that in hardened steel the magnetism ought to take place only in the direction over which the pointed magnet is drawn:" by which it also appears, that he mistakes the particular in which the difficulty really lies, it not being in the direction but in the narrow limits of the magnetic influence.

In resuming the metaphysical part of the discussion, I beg to introduce it under a new head :

Observations on the Metaphysical Doctrines which arise out of Mr. Exley's new Theory of Physics.

Having gone through those observations which Mr. Exley's theory of physics has suggested, permit me, sir, to add a few thoughts on the metaphysics which grow out of it, more particularly as such an inquiry will give a new aspect to those more recondite speculations, inasmuch as it will show the possibility of connecting the ultimate researches in natural philosophy, with the first steps in mental philosophy, and the practicability of inducting from the phenomena of matter to the phenomena of mind. In these more refined investigations, we have been accustomed to depend upon and advance from the facts and observations peculiar to this department of knowledge; but if it can be shown that we are able to infer some important elementary truths in metaphysics, from the primary laws and forces of matter, we shall have enlarged the dominion and extended the triumphs of the art of induction. In this point of view, it is not necessary to admit that those laws and forces are as yet fully established; but assuming them to be correctly enounced, I proceed to reveal the consequences to which they lead in the region beyond the boundaries of physics; and by making use of a probable truth, the certainty of which may in after times be established even by experimental research, to show the possibility of scaling the barrier of separation which has hitherto been considered impassable, and of laying down lines

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of communication between those kingdoms of nature which have been thought to be utterly alien, and for ever irreconcilable. It is probable that the sagacious and prophetic observation of Sir Isaac Newton may yet be verified, that "if natural philosophy should be continued to be improved in its various branches, the bounds of moral philosophy would be enlarged also."

I trust to these observations as being sufficient to justify me for introducing a theme which is not very obviously con nected with the physical sciences, to which your valuable periodical is more immediately devoted.

It will be recollected that in a former article on this subject, I comprised under four doctrines the opinions which have been held concerning the essential nature of matter, each of which I shortly discussed. They were these:1. That material phenomena may be referred to an essence or substance which exists without any power that is essentially its own, that is, such substance is supposed not to be really endowed with power by the Divine Being, but simply, that it is by him supplied therewith continually, as the immediate emanation of his own energy; in short, that material phenomena may be referred to a created substance which exists conjointly with divine power. 2. That they may be referred to a created power which exists without any substance necessary to uphold it. 3. That they may be referred to a created substance which exists conjointly and co-essentially with a created power. 4. That they may be referred immediately and solely to the divine power. The two latter doctrines were considered by me to be either of them more tenable and rational than the two former. It is possible to imagine other doctrines, and some strange ones have in fact been promulgated, such as, 5. That the material phenomena may be referred to uncreated substance, existing co-essentially with uncreated power; and, 6. That they may be referred to the divine substance and power. These doctrines, the last of which is the Spinozaism of the west, or the Pantheism of the east, I adverted to only in reference to arguments reductio ad absurdum. From the perusal of Mr. Exley's work, I was led to consider that he held the second of

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these doctrines, namely, the existence of power without substance, that is, without its being necessary that there should exist also a substratum, in order to uphold it, and I was thence induced to offer some considerations in refutation of it. Mr. Exley, however, now asserts, that he contends for 66 "a distinct, really created, material substance," and that he upholds no doctrine of power without substance-to which declaration I, of course, defer; but I cannot so easily submit to the correctness of the assertion which immediately follows, that such doctrine "cannot be inferred from his work or theory:" I formed my opinion from the following passages in his work, and from other similar statements, and I shall think it very strange if any one after reading them should come to any other conclusion.

"Matter is perceptible to man by means of its powers acting on the senses: powers which themselves are in continual operation, and appear to constitute the very essence of matter." "These powers are denominated attraction and repulsion." ""Each atom of matter consists of an indefinitely extensive sphere of attraction, resting on a very small concentric sphere of repulsion, the force being every where from the centre, inversely as the square of the distance; repulsive near the centre, and then attractive." 66 It may be asked, are we absolutely to exclude atoms? I confess I can find no use for them." "It is nothing but a mere hypothesis and a vulgar notion, to judge that there is a minute solid impenetrable mass necessary to constitute an atom of matter on which forces act." "There appears, in fact, to be no use whatever for these infinitely small solids, and it is on this ground that I discard this ideal substratum." "We know nothing of such little solids-we have never seen them, nor felt them, nor perceived them by any of the senses; if they do exist at all, we have not been affected by them, but only by the forces of repulsion and attraction, directed in one case fron them, and in the other towards them." "It has been a question of debate much agitated among philosophers, to ascertain what it is which constitutes the nature of bodies, or rather of the matter of which they are formed. Sume make it to consist in extension,

because this attribute first presents itself to the mind; but the same rule might lead us to draw other conclusions, since different views of the subject would suggest some other attribute first to our notice. Besides, all the properties of matter ought to be derived from its nature now can this apply to extension? How can we derive from it solidity, mobility, attraction, &c. ? There may be considered simple extension without any of these. Similar difficulties press upon those, who place the essence of matter in solid extension; for how can we hence derive mobility, resistance to impressed action, attraction, or repulsion? These surely cannot flow necessarily from solid extension. Will the same objections reach our theory, which places the essence of matter in attraction and repulsion? Do not the other properties of bodies flow from this? Cannot we derive from it extension, figure, solidity, inertia, vis inertiæ, mobility, and gravity, and even divisibility, as far as it is known to extend in fact ?" "There is nothing incongru ous in the idea that a being infinite in power and wisdom, could direct a power every way from a central point to any distance he pleased; and towards the same point he could exercise a power contrary in direction, and resting on the former; and this would constitute an atom having all the properties which we observe in the elements of matter." "We know nothing of matter but by the forces which it exerts, and which doubtless constitute its nature. Matter is force applied and exerted in a peculiar way; and reciprocally, force operating in a certain mode, constitutes matter."

It will be seen from these extracts, that Mr. Exley overturns and reverses all the commonly received notions concerning matter. Instead of recognising the existence of solid extended particles, and assigning to them as properties the powers of attraction and repulsion, he converts the properties into an essence, deduces thence as necessary consequences, and not as qualities, the phenomena of solidity and extension, and dispenses with the particles altogether. Whilst he deprives us of those particles as the support or substratum of those powers, he in none of these passages, nor any where else, makes any allusion