And if here, for the mere sake of cavilling, it be urged, that although my starting-point is, as I a.s.sert, the a.s.sumption of absolute Simplicity, yet Simplicity, considered merely in itself, is no axiom; and that only deductions from axioms are indisputable-it is thus that I reply:-
Every other science than Logic is the science of certain concrete relations. Arithmetic, for example, is the science of the relations of number-Geometry, of the relations of form-Mathematics in general, of the relations of quant.i.ty in general-of whatever can be increased or diminished. Logic, however, is the science of Relation in the abstract-of absolute Relation-of Relation considered solely in itself.
An axiom in any particular science other than Logic is, thus, merely a proposition announcing certain concrete relations which seem to be too obvious for dispute-as when we say, for instance, that the whole is greater than its part:-and, thus again, the principle of the _Logical_ axiom-in other words, of an axiom in the abstract-is, simply, _obviousness of relation_. Now, it is clear, not only that what is obvious to one mind may not be obvious to another, but that what is obvious to one mind at one epoch, may be anything but obvious, at another epoch, to the same mind. It is clear, moreover, that what, to-day, is obvious even to the majority of mankind, or to the majority of the best intellects of mankind, may to-morrow be, to either majority, more or less obvious, or in no respect obvious at all. It is seen, then, that the _axiomatic principle_ itself is susceptible of variation, and of course that axioms are susceptible of similar change. Being mutable, the "truths" which grow out of them are necessarily mutable too; or, in other words, are never to be positively depended upon as truths at all-since Truth and Immutability are one.
It will now be readily understood that no axiomatic idea-no idea founded in the fluctuating principle, obviousness of relation-can possibly be so secure-so reliable a basis for any structure erected by the Reason, as _that_ idea-(whatever it is, wherever we can find it, or _if_ it be practicable to find it anywhere)-which is _ir_relative altogether-which not only presents to the understanding _no obviousness_ of relation, either greater or less, to be considered, but subjects the intellect, not in the slightest degree, to the necessity of even looking at _any relation at all_. If such an idea be not what we too heedlessly term "an axiom," it is at least preferable, as a Logical basis, to any axiom ever propounded, or to all imaginable axioms combined:-and such, precisely, is the idea with which my deductive process, so thoroughly corroborated by induction, commences. My _particle proper_ is but _absolute Irrelation_. To sum up what has been here advanced:-As a starting point I have taken it for granted, simply, that the Beginning had nothing behind it or before it-that it was a Beginning in fact-that it was a beginning and nothing different from a beginning-in short that this Beginning was--_that which it was_. If this be a "mere a.s.sumption" then a "mere a.s.sumption" let it be.
To conclude this branch of the subject:-I am fully warranted in announcing that _the Law which we have been in the habit of calling Gravity exists on account of Matter"s having been irradiated, at its origin, atomically, into a limited[4] sphere of s.p.a.ce, from one, individual, unconditional, irrelative, and absolute Particle Proper, by the sole process in which it was possible to satisfy, at the same time, the two conditions, irradiation, and generally-equable distribution throughout the sphere-that is to say, by a force varying in direct proportion with the squares of the distances between the irradiated atoms, respectively, and the Particular centre of Irradiation_.
[4] Limited sphere-A sphere is _necessarily_ limited. I prefer tautology to a chance of misconception.
I have already given my reasons for presuming Matter to have been diffused by a determinate rather than by a continuous or infinitely continued force. Supposing a continuous force, we should be unable, in the first place, to comprehend a reaction at all; and we should be required, in the second place, to entertain the impossible conception of an infinite extension of Matter. Not to dwell upon the impossibility of the conception, the infinite extension of Matter is an idea which, if not positively disproved, is at least not in any respect warranted by telescopic observation of the stars-a point to be explained more fully hereafter; and this empirical reason for believing in the original finity of Matter is unempirically confirmed. For example:-Admitting, for the moment, the possibility of understanding s.p.a.ce _filled_ with the irradiated atoms-that is to say, admitting, as well as we can, for argument"s sake, that the succession of the irradiated atoms had absolutely _no end_-then it is abundantly clear that, even when the Volition of G.o.d had been withdrawn from them, and thus the tendency to return into Unity permitted (abstractly) to be satisfied, this permission would have been nugatory and invalid-practically valueless and of no effect whatever. No Reaction could have taken place; no movement toward Unity could have been made; no Law of Gravity could have obtained.
To explain:-Grant the _abstract_ tendency of any one atom to any one other as the inevitable result of diffusion from the normal Unity:-or, what is the same thing, admit any given atom as _proposing_ to move in any given direction-it is clear that, since there is an _infinity_ of atoms on all sides of the atom proposing to move, it never can actually move toward the satisfaction of its tendency in the direction given, on account of a precisely equal and counterbalancing tendency in the direction diametrically opposite. In other words, exactly as many tendencies to Unity are behind the hesitating atom as before it; for it is a mere sotticism to say that one infinite line is longer or shorter than another infinite line, or that one infinite number is greater or less than another number that is infinite. Thus the atom in question must remain stationary forever. Under the impossible circ.u.mstances which we have been merely endeavoring to conceive for argument"s sake, there could have been no aggregation of Matter-no stars-no worlds-nothing but a perpetually atomic and inconsequential Universe. In fact, view it as we will, the whole idea of unlimited Matter is not only untenable, but impossible and preposterous.
With the understanding of a _sphere_ of atoms, however, we perceive, at once, a _satisfiable_ tendency to union. The general result of the tendency each to each, being a tendency of all to the centre, the _general_ process of condensation, or approximation, commences immediately, by a common and simultaneous movement, on withdrawal of the Divine Volition; the _individual_ approximations, or coalescences-_not_ coalitions-of atom with atom, being subject to almost infinite variations of time, degree, and condition, on account of the excessive multiplicity of relation, arising from the differences of form a.s.sumed as characterizing the atoms at the moment of their quitting the Particle Proper; as well as from the subsequent particular inequidistance, each from each.
What I wish to impress upon the reader is the certainty of there arising, at once, (on withdrawal of the diffusive force, or Divine Volition,) out of the condition of the atoms as described, at innumerable points throughout the Universal sphere, innumerable agglomerations, characterized by innumerable specific differences of form, size, essential nature, and distance each from each. The development of Repulsion (Electricity) must have commenced, of course, with the very earliest particular efforts at Unity, and must have proceeded constantly in the ratio of Coalescence-that is to say, _in that of Condensation_, or, again, of Heterogeneity.
Thus the two Principles Proper, _Attraction_ and _Repulsion_-the Material and the Spiritual-accompany each other, in the strictest fellowship, forever. Thus _The Body and The Soul walk hand in hand_.
If now, in fancy, we select _any one_ of the agglomerations considered as in their primary stages throughout the Universal sphere, and suppose this incipient agglomeration to be taking place at that point where the centre of our Sun exists-or rather where it _did_ exist originally; for the Sun is perpetually shifting his position-we shall find ourselves met, and borne onward for a time at least, by the most magnificent of theories-by the Nebular Cosmogony of Laplace:-although "Cosmogony" is far too comprehensive a term for what he really discusses-which is the const.i.tution of our solar system alone-of one among the myriad of similar systems which make up the Universe Proper-that Universal sphere-that all-inclusive and absolute _Kosmos_ which forms the subject of my present Discourse.
Confining himself to an _obviously limited_ region-that of our solar system with its comparatively immediate vicinity-and _merely_ a.s.suming-that is to say, a.s.suming without any basis whatever, either deductive or inductive-_much_ of what I have been just endeavoring to place upon a more stable basis than a.s.sumption; a.s.suming, for example, matter as diffused (without pretending to account for the diffusion) throughout, and somewhat beyond, the s.p.a.ce occupied by our system-diffused in a state of heterogeneous nebulosity and obedient to that omniprevalent law of Gravity at whose principle he ventured to make no guess;-a.s.suming all this (which is quite true, although he had no logical right to its a.s.sumption) Laplace has shown, dynamically and mathematically, that the results in such case necessarily ensuing, are those and those alone which we find manifested in the actually existing condition of the system itself.
To explain:-Let us conceive _that_ particular agglomeration of which we have just spoken-the one at the point designated by our Sun"s centre-to have so far proceeded that a vast quant.i.ty of nebulous matter has here a.s.sumed a roughly globular form; its centre being, of course, coincident with what is now, or rather was originally, the centre of our Sun; and its periphery extending out beyond the orbit of Neptune, the most remote of our planets:-in other words, let us suppose the diameter of this rough sphere to be some 6000 millions of miles. For ages, this ma.s.s of matter has been undergoing condensation, until at length it has become reduced into the bulk we imagine; having proceeded gradually, of course, from its atomic and imperceptible state, into what we understand of visible, palpable, or otherwise appreciable nebulosity.
Now, the condition of this ma.s.s implies a rotation about an imaginary axis-a rotation which, commencing with the absolute incipiency of the aggregation, has been ever since acquiring velocity. The very first two atoms which met, approaching each other from points not diametrically opposite, would, in rushing partially past each other, form a nucleus for the rotary movement described. How this would increase in velocity, is readily seen. The two atoms are joined by others:-an aggregation is formed. The ma.s.s continues to rotate while condensing. But any atom at the circ.u.mference has, of course, a more rapid motion than one nearer the centre. The outer atom, however, with its superior velocity, approaches the centre; carrying this superior velocity with it as it goes. Thus every atom, proceeding inwardly, and finally attaching itself to the condensed centre, adds something to the original velocity of that centre-that is to say, increases the rotary movement of the ma.s.s.
Let us now suppose this ma.s.s so far condensed that it occupies _precisely_ the s.p.a.ce circ.u.mscribed by the orbit of Neptune, and that the velocity with which the surface of the ma.s.s moves, in the general rotation, is precisely that velocity with which Neptune now revolves about the Sun. At this epoch, then, we are to understand that the constantly increasing centrifugal force, having gotten the better of the non-increasing centripetal, loosened and separated the exterior and least condensed stratum, or a few of the exterior and least condensed strata, at the equator of the sphere, where the tangential velocity predominated; so that these strata formed about the main body an independent ring encircling the equatorial regions:-just as the exterior portion thrown off, by excessive velocity of rotation, from a grindstone, would form a ring about the grindstone, but for the solidity of the superficial material: were this caoutchouc, or anything similar in consistency, precisely the phaenomenon I describe would be presented.
The ring thus whirled from the nebulous ma.s.s, _revolved_, of course, _as_ a separate ring, with just that velocity with which, while the surface of the ma.s.s, it _rotated_. In the meantime, condensation still proceeding, the interval between the discharged ring and the main body continued to increase, until the former was left at a vast distance from the latter.
Now, admitting the ring to have possessed, by some seemingly accidental arrangement of its heterogeneous materials, a const.i.tution nearly uniform, then this ring, _as_ such, would never have ceased revolving about its primary; but, as might have been antic.i.p.ated, there appears to have been enough irregularity in the disposition of the materials, to make them cl.u.s.ter about centres of superior solidity; and thus the annular form was destroyed.[5] No doubt, the band was soon broken up into several portions, and one of these portions, predominating in ma.s.s, absorbed the others into itself; the whole settling, spherically, into a planet. That this latter, _as_ a planet, continued the revolutionary movement which characterized it while a ring, is sufficiently clear; and that it took upon itself also, an additional movement in its new condition of sphere, is readily explained. The ring being understood as yet unbroken, we see that its exterior, while the whole revolves about the parent body, moves more rapidly than its interior. When the rupture occurred, then, some portion in each fragment must have been moving with greater velocity than the others. The superior movement prevailing, must have whirled each fragment round-that is to say, have caused it to rotate; and the direction of the rotation must, of course, have been the direction of the revolution whence it arose. _All_ the fragments having become subject to the rotation described, must, in coalescing, have imparted it to the one planet const.i.tuted by their coalescence.-This planet was Neptune. Its material continuing to undergo condensation, and the centrifugal force generated in its rotation getting, at length, the better of the centripetal, as before in the case of the parent orb, a ring was whirled also from the equatorial surface of this planet: this ring, having been ununiform in its const.i.tution, was broken up, and its several fragments, being absorbed by the most ma.s.sive, were collectively spherified into a moon. Subsequently, the operation was repeated, and a second moon was the result. We thus account for the planet Neptune, with the two satellites which accompany him.
[5] Laplace a.s.sumed his nebulosity heterogeneous, merely that he might be thus enabled to account for the breaking up of the rings; for had the nebulosity been h.o.m.ogeneous, they would not have broken. I reach the same result-heterogeneity of the secondary ma.s.ses immediately resulting from the atoms-purely from an _a priori_ consideration of their general design-_Relation_.
In throwing off a ring from its equator, the Sun re-established that equilibrium between its centripetal and centrifugal forces which had been disturbed in the process of condensation; but, as this condensation still proceeded, the equilibrium was again immediately disturbed, through the increase of rotation. By the time the ma.s.s had so far shrunk that it occupied a spherical s.p.a.ce just that circ.u.mscribed by the orbit of Ura.n.u.s, we are to understand that the centrifugal force had so far obtained the ascendency that new relief was needed: a second equatorial band was, consequently, thrown off, which, proving ununiform, was broken up, as before in the case of Neptune; the fragments settling into the planet Ura.n.u.s; the velocity of whose actual revolution about the Sun indicates, of course, the rotary speed of that Sun"s equatorial surface at the moment of the separation. Ura.n.u.s, adopting a rotation from the collective rotations of the fragments composing it, as previously explained, now threw off ring after ring; each of which, becoming broken up, settled into a moon:-three moons, at different epochs, having been formed, in this manner, by the rupture and general spherification of as many distinct ununiform rings.
By the time the Sun had shrunk until it occupied a s.p.a.ce just that circ.u.mscribed by the orbit of Saturn, the balance, we are to suppose, between its centripetal and centrifugal forces had again become so far disturbed, through increase of rotary velocity, the result of condensation, that a third effort at equilibrium became necessary; and an annular band was therefore whirled off as twice before; which, on rupture through ununiformity, became consolidated into the planet Saturn. This latter threw off, in the first place, seven uniform bands, which, on rupture, were spherified respectively into as many moons; but, subsequently, it appears to have discharged, at three distinct but not very distant epochs, three rings whose equability of const.i.tution was, by apparent accident, so considerable as to present no occasion for their rupture; thus they continue to revolve as rings. I use the phrase "_apparent_ accident;" for of accident in the ordinary sense there was, of course, nothing:-the term is properly applied only to the result of indistinguishable or not immediately traceable _law_.
Shrinking still farther, until it occupied just the s.p.a.ce circ.u.mscribed by the orbit of Jupiter, the Sun now found need of farther effort to restore the counterbalance of its two forces, continually disarranged in the still continued increase of rotation. Jupiter, accordingly, was now thrown off; pa.s.sing from the annular to the planetary condition; and, on attaining this latter, threw off in its turn, at four different epochs, four rings, which finally resolved themselves into so many moons.
Still shrinking, until its sphere occupied just the s.p.a.ce defined by the orbit of the Asteroids, the Sun now discarded a ring which appears to have had _eight_ centres of superior solidity, and, on breaking up, to have separated into eight fragments no one of which so far predominated in ma.s.s as to absorb the others. All therefore, as distinct although comparatively small planets, proceeded to revolve in orbits whose distances, each from each, may be considered as in some degree the measure of the force which drove them asunder:-all the orbits, nevertheless, being so closely coincident as to admit of our calling them _one_, in view of the other planetary orbits.
Continuing to shrink, the Sun, on becoming so small as just to fill the orbit of Mars, now discharged this planet-of course by the process repeatedly described. Having no moon, however, Mars could have thrown off no ring. In fact, an epoch had now arrived in the career of the parent body, the centre of the system. The _de_crease of its nebulosity, which is the _in_crease of its density, and which again is the _de_crease of its condensation, out of which latter arose the constant disturbance of equilibrium-must, by this period, have attained a point at which the efforts for restoration would have been more and more ineffectual just in proportion as they were less frequently needed. Thus the processes of which we have been speaking would everywhere show signs of exhaustion-in the planets, first, and secondly, in the original ma.s.s.
We must not fall into the error of supposing the decrease of interval observed among the planets as we approach the Sun, to be in any respect indicative of an increase of frequency in the periods at which they were discarded. Exactly the converse is to be understood. The longest interval of time must have occurred between the discharges of the two interior; the shortest, between those of the two exterior, planets. The decrease of the interval of s.p.a.ce is, nevertheless, the measure of the density, and thus inversely of the condensation, of the Sun, throughout the processes detailed.
Having shrunk, however, so far as to fill only the orbit of our Earth, the parent sphere whirled from itself still one other body-the Earth-in a condition so nebulous as to admit of this body"s discarding, in its turn, yet another, which is our Moon;-but here terminated the lunar formations.
Finally, subsiding to the orbits first of Venus and then of Mercury, the Sun discarded these two interior planets; neither of which has given birth to any moon.
Thus from his original bulk-or, to speak more accurately, from the condition in which we first considered him-from a partially spherified nebular ma.s.s, _certainly_ much more than 5,600 millions of miles in diameter-the great central orb and origin of our solar-planetary-lunar system, has gradually descended, by condensation, in obedience to the law of Gravity, to a globe only 882,000 miles in diameter; but it by no means follows, either that its condensation is yet complete, or that it may not still possess the capacity of whirling from itself another planet.
I have here given-in outline of course, but still with all the detail necessary for distinctness-a view of the Nebular Theory as its author himself conceived it. From whatever point we regard it, we shall find it _beautifully true_. It is by far too beautiful, indeed, _not_ to possess Truth as its essentiality-and here I am very profoundly serious in what I say. In the revolution of the satellites of Ura.n.u.s, there does appear something seemingly inconsistent with the a.s.sumptions of Laplace; but that _one_ inconsistency can invalidate a theory constructed from a million of intricate consistencies, is a fancy fit only for the fantastic. In prophecying, confidently, that the apparent anomaly to which I refer, will, sooner or later, be found one of the strongest possible corroborations of the general hypothesis, I pretend to no especial spirit of divination. It is a matter which the only difficulty seems _not_ to foresee.[6]
[6] I am prepared to show that the anomalous revolution of the satellites of Ura.n.u.s is a simply perspective anomaly arising from the inclination of the axis of the planet.
The bodies whirled off in the processes described, would exchange, it has been seen, the superficial _rotation_ of the orbs whence they originated, for a _revolution_ of equal velocity about these orbs as distant centres; and the revolution thus engendered must proceed, so long as the centripetal force, or that with which the discarded body gravitates toward its parent, is neither greater nor less than that by which it was discarded; that is, than the centrifugal, or, far more properly, than the tangential, velocity. From the unity, however, of the origin of these two forces, we might have expected to find them as they are found-the one accurately counterbalancing the other. It has been shown, indeed, that the act of whirling-off is, in every case, merely an act for the preservation of the counterbalance.
After referring, however, the centripetal force to the omniprevalent law of Gravity, it has been the fashion with astronomical treatises, to seek beyond the limits of mere Nature-that is to say, of _Secondary_ Cause-a solution of the phaenomenon of tangential velocity. This latter they attribute directly to a _First_ Cause-to G.o.d. The force which carries a stellar body around its primary they a.s.sert to have originated in an impulse given immediately by the finger-this is the childish phraseology employed-by the finger of Deity itself. In this view, the planets, fully formed, are conceived to have been hurled from the Divine hand, to a position in the vicinity of the suns, with an impetus mathematically adapted to the ma.s.ses, or attractive capacities, of the suns themselves.
An idea so grossly unphilosophical, although so supinely adopted, could have arisen only from the difficulty of otherwise accounting for the absolutely accurate adaptation, each to each, of two forces so seemingly independent, one of the other, as are the gravitating and tangential.
But it should be remembered that, for a long time, the coincidence between the moon"s rotation and her sidereal revolution-two matters seemingly far more independent than those now considered-was looked upon as positively miraculous; and there was a strong disposition, even among astronomers, to attribute the marvel to the direct and continual agency of G.o.d-who, in this case, it was said, had found it necessary to interpose, specially, among his general laws, a set of subsidiary regulations, for the purpose of forever concealing from mortal eyes the glories, or perhaps the horrors, of the other side of the Moon-of that mysterious hemisphere which has always avoided, and must perpetually avoid, the telescopic scrutiny of mankind. The advance of Science, however, soon demonstrated-what to the philosophical instinct needed _no_ demonstration-that the one movement is but a portion-something more, even, than a consequence-of the other.
For my part, I have no patience with fantasies at once so timorous, so idle, and so awkward. They belong to the veriest _cowardice_ of thought.
That Nature and the G.o.d of Nature are distinct, no thinking being can long doubt. By the former we imply merely the laws of the latter. But with the very idea of G.o.d, omnipotent, omniscient, we entertain, also, the idea of _the infallibility_ of his laws. With Him there being neither Past nor Future-with Him all being _Now_-do we not insult him in supposing his laws so contrived as not to provide for every possible contingency?-or, rather, what idea _can_ we have of _any_ possible contingency, except that it is at once a result and a manifestation of his laws? He who, divesting himself of prejudice, shall have the rare courage to think absolutely for himself, cannot fail to arrive, in the end, at the condensation of _laws_ into _Law_-cannot fail of reaching the conclusion that _each law of Nature is dependent at all points upon all other laws_, and that all are but consequences of one primary exercise of the Divine Volition. Such is the principle of the Cosmogony which, with all necessary deference, I here venture to suggest and to maintain.
In this view, it will be seen that, dismissing as frivolous, and even impious, the fancy of the tangential force having been imparted to the planets immediately by "the finger of G.o.d," I consider this force as originating in the rotation of the stars:-this rotation as brought about by the in-rushing of the primary atoms, towards their respective centres of aggregation:-this in-rushing as the consequence of the law of Gravity:-this law as but the mode in which is necessarily manifested the tendency of the atoms to return into imparticularity:-this tendency to return as but the inevitable reaction of the first and most sublime of Acts-that act by which a G.o.d, self-existing and alone existing, became all things at once, through dint of his volition, while all things were thus const.i.tuted a portion of G.o.d.
The radical a.s.sumptions of this Discourse suggest to me, and in fact imply, certain important _modifications_ of the Nebular Theory as given by Laplace. The efforts of the repulsive power I have considered as made for the purpose of preventing contact among the atoms, and thus as made in the ratio of the approach to contact-that is to say, in the ratio of condensation.[7] In other words, _Electricity_, with its involute phaenomena, heat, light and magnetism, is to be understood as proceeding as condensation proceeds, and, of course, inversely as density proceeds, or the _cessation to condense_. Thus the Sun, in the process of its aggregation, must soon, in developing repulsion, have become excessively heated-perhaps incandescent: and we can perceive how the operation of discarding its rings must have been materially a.s.sisted by the slight incrustation of its surface consequent on cooling. Any common experiment shows us how readily a crust of the character suggested, is separated, through heterogeneity, from the interior ma.s.s. But, on every successive rejection of the crust, the new surface would appear incandescent as before; and the period at which it would again become so far encrusted as to be readily loosened and discharged, may well be imagined as exactly coincident with that at which a new effort would be needed, by the whole ma.s.s, to restore the equilibrium of its two forces, disarranged through condensation. In other words:-by the time the electric influence (Repulsion) has prepared the surface for rejection, we are to understand that the gravitating influence (Attraction) is precisely ready to reject it. Here, then, as everywhere, _the Body and the Soul walk hand in hand_.
[7] See page 70.
These ideas are empirically confirmed at all points. Since condensation can never, in any body, be considered as absolutely at an end, we are warranted in antic.i.p.ating that, whenever we have an opportunity of testing the matter, we shall find indications of resident luminosity in _all_ the stellar bodies-moons and planets as well as suns. That our Moon is strongly self-luminous, we see at her every total eclipse, when, if not so, she would disappear. On the dark part of the satellite, too, during her phases, we often observe flashes like our own Auroras; and that these latter, with our various other so-called electrical phaenomena, without reference to any more steady radiance, must give our Earth a certain appearance of luminosity to an inhabitant of the Moon, is quite evident. In fact, we should regard all the phaenomena referred to, as mere manifestations, in different moods and degrees, of the Earth"s feebly-continued condensation.
If my views are tenable, we should be prepared to find the newer planets-that is to say, those nearer the Sun-more luminous than those older and more remote:-and the extreme brilliancy of Venus (on whose dark portions, during her phases, the Auroras are frequently visible) does not seem to be altogether accounted for by her mere proximity to the central orb. She is no doubt vividly self-luminous, although less so than Mercury: while the luminosity of Neptune may be comparatively nothing.
Admitting what I have urged, it is clear that, from the moment of the Sun"s discarding a ring, there must be a continuous diminution both of his heat and light, on account of the continuous encrustation of his surface; and that a period would arrive-the period immediately previous to a new discharge-when a _very material_ decrease of both light and heat, must become apparent. Now, we know that tokens of such changes are distinctly recognizable. On the Melville islands-to adduce merely one out of a hundred examples-we find traces of _ultra-tropical_ vegetation-of plants that never could have flourished without immensely more light and heat than are at present afforded by our Sun to any portion of the surface of the Earth. Is such vegetation referable to an epoch immediately subsequent to the whirling-off of Venus? At this epoch must have occurred to us our greatest access of solar influence; and, in fact, this influence must then have attained its maximum:-leaving out of view, of course, the period when the Earth itself was discarded-the period of its mere organization.
Again:-we know that there exist _non-luminous suns_-that is to say, suns whose existence we determine through the movements of others, but whose luminosity is not sufficient to impress us. Are these suns invisible merely on account of the length of time elapsed since their discharge of a planet? And yet again:-may we not-at least in certain cases-account for the sudden appearances of suns where none had been previously suspected, by the hypothesis that, having rolled with encrusted surfaces throughout the few thousand years of our astronomical history, each of these suns, in whirling off a new secondary, has at length been enabled to display the glories of its still incandescent interior?-To the well-ascertained fact of the proportional increase of heat as we descend into the Earth, I need of course, do nothing more than refer:-it comes in the strongest possible corroboration of all that I have said on the topic now at issue.
In speaking, not long ago, of the repulsive or electrical influence, I remarked that "the important phaenomena of vitality, consciousness, and thought, whether we observe them generally or in detail, seem to proceed _at least in the ratio of the heterogeneous_."[8] I mentioned, too, that I would recur to the suggestion:-and this is the proper point at which to do so. Looking at the matter, first, in detail, we perceive that not merely the _manifestation_ of vitality, but its importance, consequence, and elevation of character, keep pace, very closely, with the heterogeneity, or complexity, of the animal structure. Looking at the question, now, in its generality, and referring to the first movements of the atoms towards ma.s.s-const.i.tution, we find that heterogeneousness, brought about directly through condensation, is proportional with it forever. We thus reach the proposition that _the importance of the development of the terrestrial vitality proceeds equably with the terrestrial condensation_.
[8] Page 36.
Now this is in precise accordance with what we know of the succession of animals on the Earth. As it has proceeded in its condensation, superior and still superior races have appeared. Is it impossible that the successive geological revolutions which have attended, at least, if not immediately caused, these successive elevations of vitalic character-is it improbable that these revolutions have themselves been produced by the successive planetary discharges from the Sun-in other words, by the successive variations in the solar influence on the Earth? Were this idea tenable, we should not be unwarranted in the fancy that the discharge of yet a new planet, interior to Mercury, may give rise to yet a new modification of the terrestrial surface-a modification from which may spring a race both materially and spiritually superior to Man. These thoughts impress me with all the force of truth-but I throw them out, of course, merely in their obvious character of suggestion.
The Nebular Theory of Laplace has lately received far more confirmation than it needed, at the hands of the philosopher, Compte. These two have thus together shown-_not_, to be sure, that Matter at any period actually existed as described, in a state of nebular diffusion, but that, admitting it so to have existed throughout the s.p.a.ce and much beyond the s.p.a.ce now occupied by our solar system, _and to have commenced a movement towards a centre_-it must gradually have a.s.sumed the various forms and motions which are now seen, in that system, to obtain. A demonstration such as this-a dynamical and mathematical demonstration, as far as demonstration can be-unquestionable and unquestioned-unless, indeed, by that unprofitable and disreputable tribe, the professional questioners-the mere madmen who deny the Newtonian law of Gravity on which the results of the French mathematicians are based-a demonstration, I say, such as this, would to most intellects be conclusive-and I confess that it is so to mine-of the validity of the nebular hypothesis upon which the demonstration depends.
That the demonstration does not _prove_ the hypothesis, according to the common understanding of the word "proof," I admit, of course. To show that certain existing results-that certain established facts-may be, even mathematically, accounted for by the a.s.sumption of a certain hypothesis, is by no means to establish the hypothesis itself. In other words:-to show that, certain data being given, a certain existing result might, or even _must_, have ensued, will fail to prove that this result _did_ ensue, _from the data_, until such time as it shall be also shown that there are, _and can be_, no other data from which the result in question might _equally_ have ensued. But, in the case now discussed, although all must admit the deficiency of what we are in the habit of terming "proof," still there are many intellects, and those of the loftiest order, to which _no_ proof could bring one iota of additional _conviction_. Without going into details which might impinge upon the Cloud-Land of Metaphysics, I may as well here observe that the force of conviction, in cases such as this, will always, with the right-thinking, be proportional to the amount of _complexity_ intervening between the hypothesis and the result. To be less abstract:-The greatness of the complexity found existing among cosmical conditions, by rendering great in the same proportion the difficulty of accounting for all these conditions _at once_, strengthens, also in the same proportion, our faith in that hypothesis which does, in such manner, satisfactorily account for them:-and as _no_ complexity can well be conceived greater than that of the astronomical conditions, so no conviction can be stronger-to _my_ mind at least-than that with which I am impressed by an hypothesis that not only reconciles these conditions, with mathematical accuracy, and reduces them into a consistent and intelligible whole, but is, at the same time, the _sole_ hypothesis by means of which the human intellect has been ever enabled to account for them _at all_.
A most unfounded opinion has become latterly current in gossiping and even in scientific circles-the opinion that the so-called Nebular Cosmogony has been overthrown. This fancy has arisen from the report of late observations made, among what hitherto have been termed the "nebulae," through the large telescope of Cincinnati, and the world-renowned instrument of Lord Rosse. Certain spots in the firmament which presented, even to the most powerful of the old telescopes, the appearance of nebulosity, or haze, had been regarded for a long time as confirming the theory of Laplace. They were looked upon as stars in that very process of condensation which I have been attempting to describe.
Thus it was supposed that we "had ocular evidence"-an evidence, by the way, which has always been found very questionable-of the truth of the hypothesis; and, although certain telescopic improvements, every now and then, enabled us to perceive that a spot, here and there, which we had been cla.s.sing among the nebulae, was, in fact, but a cl.u.s.ter of stars deriving its nebular character only from its immensity of distance-still it was thought that no doubt could exist as to the actual nebulosity of numerous other ma.s.ses, the strong-holds of the nebulists, bidding defiance to every effort at segregation. Of these latter the most interesting was the great "nebulae" in the constellation Orion:-but this, with innumerable other mis-called "nebulae," when viewed through the magnificent modern telescopes, has become resolved into a simple collection of stars. Now this fact has been very generally understood as conclusive against the Nebular Hypothesis of Laplace; and, on announcement of the discoveries in question, the most enthusiastic defender and most eloquent popularizer of the theory, Dr. Nichol, went so far as to "admit the necessity of abandoning" an idea which had formed the material of his most praiseworthy book.[9]
[9] "_Views of the Architecture of the Heavens._" A letter, purporting to be from Dr. Nichol to a friend in America, went the rounds of our newspapers, about two years ago, I think, admitting "the necessity" to which I refer. In a subsequent Lecture, however, Dr. N. appears in some manner to have gotten the better of the necessity, and does not quite _renounce_ the theory, although he seems to wish that he could sneer at it as "a purely hypothetical one." What else was the Law of Gravity before the Maskelyne experiments? and who questioned the Law of Gravity, even then?
Many of my readers will no doubt be inclined to say that the result of these new investigations _has_ at least a strong _tendency_ to overthrow the hypothesis; while some of them, more thoughtful, will suggest that, although the theory is by no means disproved through the segregation of the particular "nebulae," alluded to, still a _failure_ to segregate them, with such telescopes, might well have been understood as a triumphant _corroboration_ of the theory:-and this latter cla.s.s will be surprised, perhaps, to hear me say that even with _them_ I disagree. If the propositions of this Discourse have been comprehended, it will be seen that, in my view, a failure to segregate the "nebulae" would have tended to the refutation, rather than to the confirmation, of the Nebular Hypothesis.
Let me explain:-The Newtonian Law of Gravity we may, of course, a.s.sume as demonstrated. This law, it will be remembered, I have referred to the reaction of the first Divine Act-to the reaction of an exercise of the Divine Volition temporarily overcoming a difficulty. This difficulty is that of forcing the normal into the abnormal-of impelling that whose originality, and therefore whose rightful condition, was _One_, to take upon itself the wrongful condition of _Many_. It is only by conceiving this difficulty as _temporarily_ overcome, that we can comprehend a reaction. There could have been no reaction had the act been infinitely continued. So long as the act _lasted_, no reaction, of course, could commence; in other words, no _gravitation_ could take place-for we have considered the one as but the manifestation of the other. But gravitation _has_ taken place; therefore the act of Creation has ceased: and gravitation has long ago taken place; therefore the act of Creation has long ago ceased. We can no more expect, then, to observe _the primary processes_ of Creation; and to these primary processes the condition of nebulosity has already been explained to belong.