forces-a postulate which, as we have seen, is necessitated by the form of our experience and rhythm is an inevitable corollary from the persistence of force.

[NOTE. In the Edinburgh Review for January, 1884, there was an antagonistic criticism of this work. The writer of the criticism, Lord Grimthorpe, made much of the exception furnished by non-periodic comets to the law above set forth. I was about to admit this exception when, on looking into the matter, I found no need for doing so. Though five or six cometary orbits are said to be hyperbolic, yet, as I learn from one who has paid special attention to comets (having tabulated the directions of their aphelia), “no such orbit has, I believe, been computed for a well-observed comet." Hence the probability that all the orbits are ellipses is overwhelming. Ellipses and hyperbolas have countless varieties of forms, but there is only one form of parabola; or, to speak literally, all parabolas are similar, while there are infinitely numerous dissimilar ellipses and dissimilar hyperbolas. Consequently, anything coming to the Sun from a great distance must have one exact amount of proper motion to produce a parabola: all other amounts would give hyperbolas or ellipses. And if there are no hyperbolic orbits, then it is infinity to one that all the orbits are elliptical.]

CHAPTER XI.

RECAPITULATION, CRITICISM, AND RECOMMENCEMENT.

§ 89. LET us pause awhile to consider how far the contents of the foregoing chapters go towards forming a body of knowledge such as was defined at the outset as constituting Philosophy.

In respect of its generality, the proposition enunciated and exemplified in each chapter, is of the required kind-—is a proposition transcending those class-limits which Science, as currently understood, recognizes. "The Indestructibility of Matter" is a truth not belonging to mechanics more than to chemistry, a truth assumed alike by molecular physics and the physics that deals with sensible masses, a truth which the astronomer and the biologist equally take for granted. Not merely do those divisions of Science which Ideal with the movements of celestial and terrestrial bodies postulate "The Continuity of Motion," but it is no less postulated in the physicist's investigations into the phenomena of light and heat, and is tacitly, if not avowedly, implied in the generalizations of the higher sciences. So, too, "The Persistence of Force," involved in each of the preceding propositions, is co-extensive with them, as is also its corollary," The Persistence of Relations among Forces." These are not truths of a high generality, but they are universal truths. Passing to the deductions drawn from them, we see the same thing. That force is transformable, and that between its correlates there exist quantitative

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equivalences, are ultimate facts not to be classed with those of mechanics, or thermology, or electricity, or magnetism; but they are illustrated throughout phenomena of every order, up to those of mind and society. Similarly, the law that motion follows the line of least resistance or the line of greatest traction or the resultant of the two, we found to be an all-pervading law; conformed to alike by each planet in its orbit, and by the moving matters, aërial, liquid, and solid, on its surface-conformed to no less by every organic movement and process than by every inorganic movement and process. And so likewise, in the chapter just closed, it has been shown that rhythm is exhibited universally, from the slow gyrations of double stars down to the inconceivably rapid oscillations of molecules from such terrestrial changes as those of recurrent glacial epochs and gradually alternating elevations and subsidences, down to those of the winds and tides and waves; and is no less conspicuous in the functions of living organisms, from the pulsations of the heart up to the paroxysms of the emotions.

Thus these truths have the character which constitutes them parts of Philosophy, properly so called. They are truths which unify concrete phenomena belonging to all divisions of Nature; and so must be components of that complete, coherent conception of things which Philosophy seeks.

§ 90. But now what parts do these truths play in forming such a conception? Does any one of them singly convey an idea of the Cosmos: meaning by this word the totality of the manifestations of the Unknowable? Do all of them taken together yield us an adequate idea of this kind? Do they even when thought of in combination compose anything like such an idea? To each of these questions the answer must be-No.

Neither these truths nor any other such truths, separately or jointly, constitute that integrated knowledge in which

only Philosophy finds its goal. It has been supposed by one thinker that when Science has succeeded in reducing all more complex laws to some most simple law, as of molecular action, knowledge will have reached its limit. Another authority has tacitly asserted that all minor facts are so merged in the major fact that the force everywhere in action is nowhere lost, that to express this is to express "the constitution of the universe." But either conclusion implies a misapprehension of the problem.

For these are all analytical truths, and no analytical truth-no number of analytical truths, will make up that synthesis of thought which alone can be an interpretation of the synthesis of things. The decomposition of phenomena into their elements, is but a preparation for understanding phenomena in their state of composition, as actually manifested. To have ascertained the laws of the factors is not at all to have ascertained the laws of their co-operation. The question is, not how any factor, Matter or Motion or Force, behaves by itself, or under some imagined simple conditions; nor is it even how one factor behaves under the complicated conditions of actual existence. The thing to be expressed is the joint product of the factors under all its various aspects. Only when we can formulate the total process, have we gained that knowledge of it which Philosophy aspires to. A clear comprehension of this matter is important enough to justify some further exposition.

§ 91. Suppose a chemist, a geologist, and a biologist, have given the deepest explanations furnished by their respective sciences, of the processes going on in a burning candle, in a region changed by earthquake, and in a growing plant. To the assertion that their explanations are not the deepest possible, they will probably rejoin—“ What would you have? What remains to be said of combustion when light and heat and the dissipation of substance have all been traced down to the liberation of molecular motion

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as their common cause? When all the actions accompanying an earthquake are explained as consequent upon the slow loss of the Earth's internal heat, how is it possible to go lower? When the influence of light on the oscillations of molecules has been proved to account for vegetal growth, what is the imaginable further rationale? You ask for a synthesis. You say that knowledge does not end in the resolution of phenomena into the actions of certain factors, each conforming to ascertained laws; but that the laws of the factors having been ascertained, there comes the chief problem-to show how from their joint action result the phenomena in all their complexity. Well, do not the above interpretations satisfy this requirement? Do we not, starting with the molecular motions of the elements concerned in combustion, build up synthetically an explanation of the light, and the heat, and the produced gases, and the movements of the produced gases? Do we not, setting out from the still-continued radiation of its heat, construct by synthesis a clear conception of the Earth's nucleus as contracting, its crust as collapsing, as becoming shaken and fissured and contorted and burst through by lava? And is it not the same with the chemical changes and accumulation of matter in the growing plant?"

To all which the reply is, that the ultimate interpretation to be reached by Philosophy, is a universal synthesis comprehending and consolidating such special syntheses. The synthetic explanations which Science gives, even up to the most general, are more or less independent of one another. Though they may have like elements in them, they are not united by the likeness of their essential structures. Is it to be supposed that in the burning candle, in the quaking Earth, and in the organism that is increasing, the processes as wholes are unrelated to one another? If it is admitted that each of the factors concerned always operates in conformity to a law, is it to be concluded that their co-operation conforms to no law? These various changes,