Fables of Infidelity and Facts of Faith Part 21

"In the present state of things, these eccentricities and these inclinations are totally incompatible with Olbers' hypothesis, which supposed that the small planets--some of which were discovered even in his day--were produced from the wreck of a larger star, which had exploded. The forces necessary to launch the fragments of a given body in such different routes (whose existence we should be obliged to suppose) would be of such an improbable intensity, that the most limited mathematical knowledge could not but see its absurdity." He concludes the memoir by advancing four propositions, "which forever annihilate Olbers' hypothesis."[198]

3. _The progress of astronomical discovery has utterly refuted the notion of creation by natural law, known as the Development Theory, or the Nebular Hypothesis._

Scientific Infidels knew that there was too much order and regularity in the motions of the planets to allow any rational mind to ascribe these motions to accident, according to Buffon's notion. They saw that these movements must be regulated by law. La Place, an eminent mathematician, saw that there are at least five great regularities pervading the system, for which Buffon's theory gave no reason:

1. The planets all move in elliptical orbits, nearly circular. They might, on the contrary, have been as elongated as those of comets.

2. They revolve in orbits nearly in the plane of the sun's equator. They might have revolved in orbits inclined to it at any angle, or even in the plane of his poles.

3. They revolve around the sun all in the same direction, which is the direction of his rotation on his axis.

4. They rotate on their axes, also, so far as known, in the same direction.

5. The satellites (with the exception of those of Ura.n.u.s) revolve around their primary planets, and also rotate on their axes, in the same normal direction.

It was evident, even to the believers in chance, that so many regularities were not produced by accident. La Place found, by computing the chances by the formula of probabilities, that the chances were two millions to one against these regularities happening by chance, _and four millions to one in favor of these motions having a common origin_.

The grand phenomenon being a motion of rotation in the whole system, of which the rotation of the sun is the central part, he thought if he could account for this, he could explain all the rest.

He set out by supposing, that the sun and planets originally existed as a vast cloud of gaseous matter, intensely heated--a vast fire-mist--placed in a region of s.p.a.ce much cooler, and that this cloud, by gradual cooling, and the pressure of its parts, settled down into solid forms. It was supposed that some portions of this cloud would begin to cool sooner than others, and so become solid sooner, and that the hot gas, rushing to the solid part, would form a vortex, which would set the cloud in motion around its center. As the speed of its rotation would increase, and the outside condense and grow solid before the inside, the cloud would whirl off the rings of solid matter, which would keep revolving in the same orbits in which they were cast off, and would revolve faster and faster as they grew cooler and more solid, till they broke up, by the force of their velocity, into smaller pieces; which fragments, in their turn, repeated the process, until the present number of planets and their satellites was produced.[199]

This theory differs from Buffon's much as a low pressure engine, deriving most of its power from the condenser, differs from one of high pressure. La Place does not explode the boiler to make his planets, but merely runs his train so fast as to break an axle every now and then, when the wheel runs off with the velocity it has got, and keeps its track as well as if it had an engineer to guide it, grows into a little locomotive by dint of running, and after a while breaks an axle too--breaking is a hereditary failing of these suns and planets that had no G.o.d to make them--and the wheels thus thrown off supply it with moons and rings, like Saturn's. The ill.u.s.tration is not nearly so absurd as the theory, inasmuch as a locomotive is an incomparably less complicated contrivance than a planet. However the nonsense was cradled in the halls of philosophy by means of antiquity, and distance.

As no fiction was too marvelous for the credence of the Greek, if it were only a hundred years old, or located beyond the Euxine, so to our development philosopher any impossibility may be accepted, if it can only be dissolved into gas, and located a good many millions of miles away; and to make it an article of faith on which he will risk his soul, it is only necessary to give it a remote antiquity. No Papist ever insisted more on antiquity as the solvent of all absurdity. Antiquity, distance, and expansion are his trinity, with which all absurdities become scientific facts.

Herschel had discovered numbers of nebulae, or luminous clouds, in the distant heavens shining with a distinct light, but which, with the highest magnifying power he could apply, presented no trace of stars.

Some nebulae, it is true, his largest telescope resolved, like our own Milky Way, into beds of distinct stars; but there were others--for instance, one in the belt of Orion--visible to the naked eye as a cloud, but which his forty feet telescope only displayed as a larger cloud, without any shape of stars. Now, reasoning upon the matter, he found that if these nebulae were composed of stars as large as those distinctly visible, they must be immensely distant to be indistinguishable by his telescope, and exceedingly numerous and close together to give a cloud of light visible to the naked eye. In fact, the suns of those firmaments must be so close to each other as to present a blaze of glory, and complexities of revolution inconceivable to the dwellers on earth. But as this daring idea seemed incredible, even to his giant mind, he thought the appearance of these nebulae might be more rationally accounted for by supposing that they were not stars at all, but simply clouds of gaseous matter, like the matter of comets, from which he supposed that stars were formed by a long process of condensation and solidification. He thought this theory was favored by the fact, that nebulae are generally seen in those portions of the heavens that are not thickly strewn with stars; and also by the various forms of these clouds. Some were merely loose clouds, without any definite form; others seemed gathering toward the center. In some, of a roundish, or oval form, the central ma.s.s seemed well defined. In a few, the process seemed nearly complete, a bright star shining in the midst of a faint nebulous halo. Here, then, it was said, we see the whole progress of the growth of stars; their development from the gaseous nebulous fluid into solid, brilliant suns. La Place accepted Herschel's discoveries as conclusive proof of the truth of his theory, and it was generally accepted by the scientific world. Oddly enough, Infidels seem not to have noticed that those appearances of _condensation toward the center_, which seemed to Herschel so strongly in favor of his theory of the nebulous fluid, were diametrically opposed to La Place's requirements of _condensation at the circ.u.mference_; and these two contradictory notions were supposed to support each other, and to furnish a solid basis for the development hypothesis.

This theory, as stated by Herschel, and expounded by Nichol, d.i.c.k, and other Christian writers, _is not necessarily Atheistical_. On the contrary, they allege that it furnishes us with greater evidences of the power of G.o.d, and gives us higher ideas of his wisdom, to suppose a system of creation by development, under natural law, than by a direct exercise of his will. Undoubtedly, had G.o.d so pleased he could have made suns from fire-mists, according to some plan which his infinite wisdom could devise, and his omnipotent power could execute; but it is beyond the possibilities even of omniscience and omnipotence to make worlds, or to make anything but nonsense, according to La Place's plan. Had G.o.d so pleased, to make firmaments grow as forests do, and if he should please to enable us to discover such celestial growth in some distant part of heaven, we should have the same kind of evidence of his being, power, wisdom, and goodness in this creation by natural law which we now have from his providence by natural law, in the growth of the fruits of the earth, and as much greater an amount of it as the heavens are greater than the earth. The first beginning of primeval elements demands a Creator. The contrivance of the law of development proclaims a Contriver. The force by which it operates--whether that of gravity or chemical reaction--must be the force of an Agent.

_The development theory, then, fails to account for the origin of the universe, or even of our own world._ Herbert Spencer, its most eloquent expounder, admits this. He says: "It remains only to point out that while the genesis of the solar system, and of countless other systems like it, is thus rendered comprehensible, the ultimate mystery continues as great as ever. The problem of existence is not solved; it is simply removed farther back. The Nebular Hypothesis throws no light on the origin of diffused matter; and diffused matter as much needs accounting for as concrete matter. The genesis of an atom is not easier to conceive than the genesis of a planet. Nay, indeed, so far from making the universe a less mystery than before, it makes it a greater mystery.

Creation by manufacture is a much lower thing than creation by evolution. A man can put together a machine, but he can not make a machine develop itself. The ingenious artisan, able as some have been, so far to imitate vitality as to produce a mechanical piano-forte player, may in some sort conceive how, by greater skill, a complete man might be artificially produced; but he is unable to conceive how such a complex organism gradually arises out of a minute, structureless germ.

That our harmonious universe once existed potentially as formless, diffused matter, and has slowly grown into its present organized state, is a far more astonishing fact than would have been its formation after the artificial method vulgarly supposed. Those who hold it legitimate to argue from phenomena to noumena, may rightly contend that the Nebular Hypothesis implies a First Cause as much transcending 'the mechanical G.o.d of Paley,' as this does the fetish of a savage."[200]

The Nebular Hypothesis, then, can not exist without G.o.d. However, as it seems to remove him to a great distance from this present world, both in s.p.a.ce and time, it has become popular with Atheists.

The Nebular Hypothesis, as presented by Atheists, _imagines a state of primeval matter as simple, or h.o.m.ogeneous, of which science presents no example, in heaven or on earth_.

This h.o.m.ogeneous condition of matter is the very foundation of the theory. Spencer reasons at great length, that all progress is from the simple to the differentiated. And it is indispensable for the Atheists to prove that the primeval world was composed of matter perfectly simple and h.o.m.ogeneous. If they alleged that it was composed of several ingredients, n.o.body would believe them that this compound was eternal.

There is no conviction of common sense stronger than that every compound has been put together by some compounder.

They could not persuade a child that a plum pudding made itself, or that a steamship filled with pa.s.sengers existed so from eternity, much less a planet with a much larger crew and company. They therefore alleged that the first matter of the universe was perfectly h.o.m.ogeneous and simple.

When common people objected that no such thing was to be seen in this world nowadays, since all things here--stones, water, air, earth, plants, animals--are compounded and built up out of a great variety of matters, they claimed that this is the result of the growth of our planet; but that the nebulae, which astronomers see far away in the sky, are young suns and planets, just beginning to condense, and that the gas they consist of is the genuine, simple, h.o.m.ogeneous matter out of which this world, and all worlds, originally made themselves. They thought the nebulae were so very far away that n.o.body would ever go there to see and come back to contradict them; and so they were quite safe in pointing to them as examples of h.o.m.ogeneous matter.

Now one does not see, if the nebula had been exactly what the development men a.s.sert--_simple, h.o.m.ogeneous matter_--_how they could ever have made such a composite world as this out of it_, or indeed how they could make anything but itself out of it. No chemical actions or reactions can begin in a simple substance; there must always be at least two simple substances to make a compound. Heating or cooling a simple substance will never make it a compound. You may heat water in a boiler and cool it again as often as you please, but your heating and cooling will never make coffee out of it, unless you put coffee into it. So you may heat and cool your simple nebula to all eternity, but you will never get coffee out of it, much less coffee and coffee-pot, china and company, with the biscuits and b.u.t.ter; all which, and a great deal more, our philosophers contrive to churn out of the primeval h.o.m.ogeneous nebula.

But the progress of science has enabled us to show that the nebulae, far from being simple, h.o.m.ogeneous matter, are compounded of as many ingredients as the flame of your lamp or gas light, which is combined of half a score of different substances. By the discovery of Spectrum a.n.a.lysis we are able to a.n.a.lyze the chemical composition of the most distant flames, to tell whether they proceed from solids or gases in a state of combustion, and what are the gases and minerals consumed in them. As s.p.a.ce forbids the details of this discovery here, I can only state the results, namely that some of the nebulae consist of clouds of small solid stars, of which the nebula in Orion is an instance; but others consist of flames of gases, in all cases compound, and showing, besides the oxygenated flame, the lines which declare the presence of hydrogen, and of several metals. Thus it is proved, that no such eternal, h.o.m.ogeneous nebulae are to be found in heaven, and consequently n.o.body could ever make worlds out of a substance which had no existence.

This theory of development was always _a mere notion, a castle in the air_, and never could be anything more. To say that it was mere moonshine would be to give it far too respectable a standing; for moonshine has a real existence, and may be seen and felt. But n.o.body ever saw or felt a h.o.m.ogeneous nebula. Indeed, its inventor never pretended that he, or anybody else, ever saw one; or saw it sailing off into moons, and planets, and suns, or ever would see any such thing. No scientific man has ever pretended that it was an established fact, or anything more than a theory, a notion. Young people, who are invited to hazard their souls on the strength of this miscalled scientific theory, should remember that it is not science, which means something a man knows, but merely a theory, which is some notion which he imagines.

_It is an unsatisfactory notion._ It does not answer the purpose of its inventors. As we have already seen, it gives us no account of the origin of the h.o.m.ogeneous matter of the nebula. It gives no answer to the questions, How did it get to be so hot, while all the s.p.a.ce around it was so cold? Is the fire that heated it burning still, or is it exhausted for want of fuel? Were the germs of all the plants and animals in it while it was blazing at a white heat? If they were, how did they escape being burnt to ashes? If they were not, where did they come from?

For there was nothing but that nebula then in existence. Did it contain within itself all the principles of things, all the forces now found in the worlds which grew out of it? If so, how came they there? If not, how did attraction, and repulsion, vegetable life, animal life, intellect, and free will, work themselves into that cloud of h.o.m.ogeneous gas?

Professor Tyndall thus exposes the absurdity of the supposition that the nebula contained the elements of mind: "For what are the core and essence of this hypothesis? Strip it naked and you stand face to face with the notion that not alone the more ign.o.ble forms of animalcular or animal life, not alone the n.o.ble forms of the horse and lion, not alone the exquisite and wonderful mechanisms of the human body, but the human mind itself--emotion, intellect, will, and all these phenomena, were once latent in a fiery cloud. Surely the mere statement of such a notion is more than a refutation."[201]

_It was only one of several contradictory notions._ Thus a writer in the _Atlantic Monthly_, so far from accepting the notion that the sun and earth are solidifying and cooling down, as explanatory of the facts revealed by astronomy and geology, infers the very contrary from the acknowledged facts, namely, that we are coming up to the nebular condition, rather than developing from it. He writes as follows:

"The earth is progressing by excessively slow changes toward the solar and nebulous condition. Its history is a repet.i.tion of the solar, and a time must arrive when the surface, becoming incandescent, will be obscured only by casual dark pits in a brilliant atmosphere, a _souvenir_ of the present darkness of the crust; yet during a certain period, within fixed limits of gravitating force and heat of ma.s.s, the human race may continue to exist; progressing, we may suppose, in force and fineness of organization. The race will perish, perhaps, in the order of nature, by failure or insufficient number of offspring, a princ.i.p.al cause of the extinction of superior races. The earth must become lone and voiceless long before the incandescence of the crust. Science may follow it into the condition of an attendant star, and then of an expanding nebula.

"In the cosmos all movements are cyclical, and recurrent, without change, save interchange among forms of motion. A universe which is, in its total, the same to-day as yesterday, and always, would appear idle and dull if it were not the footstool of divine force, upon which the creative will maintains a certain equipoise, necessary to the continued production of spiritual forms."

_It is an impracticable notion, contrary to the first principle of mechanics, that action and reaction are equal._

The grand requirement of the system--power to work the engine--can never be raised by La Place's, nor by any other mechanical plan. The cooling cloud of fire-mist is simply a very big machine, and no machine can generate power to work itself. If La Place could have somehow or other got power for the motion of rotation outside of his cloud, he might have made it revolve, and scatter off great lumps of the lightest outside stuffs, as your grindstone scatters off drops of water when you turn it rapidly; but, having no such power, his theory is a plan to make the grindstone turn itself. It is, therefore, precisely of the same value as any one of the hundred of ingenious schemes for creating power by machinery, of the perpetual motion men, in defiance of the first law of mechanics, that action and reaction are equal.

Moreover, he proposes to raise the power by making the gas cool at one part of the surface faster than at another, and so to make a vortex around that spot, which would set the whole ma.s.s to revolving. But no conceivable reason can be alleged why the h.o.m.ogeneous ma.s.s should begin to cool at one place faster than another, or indeed why an eternally hot ma.s.s should ever begin to cool at all. But, letting that pa.s.s, to make the required vortex for the rotation of the whole ma.s.s, it should not begin to cool at any part of the surface, but at the center, where, as every engine driver who ever saw a condenser, and every woman who ever cooled a dish of mush knows, it could not possibly begin to cool till the outside ma.s.s had become cold; and so no motion could be produced.

This is so well known in the machine shops that it is rare to find a machinist own the theory.

But even a more fatal objection has been raised by one of the most eloquent expounders of the theory. Mr. Spencer shows us that the ma.s.s, condensing under the influence of gravitation, so far from cooling _must necessarily evolve heat_. He is perfectly clear and decided on this matter, _that the condensing ma.s.s could never, by any possibility, begin to cool, but must begin to heat, and go on heating till it burst out in a blaze_. He says: "Heat must inevitably be generated by the aggregation of diffused matter into a concrete form; and throughout our reasonings we have a.s.sumed that such generation of heat has been an accompaniment of nebular condensation."[202] "While the condensation and the rate of rotation are progressively increasing, the approach of the atoms necessarily generates _a progressively increasing temperature_. As this temperature rises light begins to be evolved, and ultimately there results a revolving sphere of fluid matter radiating intense light and heat--a sun."[203]

This, it will be perceived, is exactly the reverse of the original nebular theory of a cooling globe, or spheroid of h.o.m.ogeneous nebular matter, diffused by intense heat, and cooling down into suns, and moons, and planets. So far as the Spencer system is accepted, it displaces La Place's theory, and the inventor accordingly works out a new theory of his own, and equally inconsistent with known facts and principles. But as Mr. Spencer candidly owns that his scheme can neither generate matter nor force, as we have already seen, it needs no further discussion in this connection.

The fact is simply this, a chemical perpetual motion is as impossible as a mechanical one. The discovery of the convertibility of forces shows this. The development theory of the generation of motion by processes of the self-heating or the self-cooling of the machine, or by chemical actions and reactions, is, in its last a.n.a.lysis, only a big perpetual motion humbug.

Even were the rotation, and the cooling process, to take place, as is supposed, _no such results would proceed from these combined operations as the case requires_; for, according to the theory, as the cooling and contracting rings revolve in the verge of a vortex of fluid less dense than themselves, one of these two results must take place: either, as is most probable, from their exceeding tenuity, the rings will break at once into fragments, when, instead of flying outward, they will sink toward the center, and, as long as they are heavier than the surrounding fluid, _they will stay there_; and, as the cooling goes on on the outside, so will the concentration of the heavier matter, till we have _one_ great spheroid, with a solid center, liquid covering, and gaseous atmosphere. A vortex will never make, nor allow to exist beyond its center, planets heavier than the fluid of which it is composed. The other alternative, and the one which La Place selected, was the supposition that the cooling and contracting rings did not at first break up into pieces, but retained their continuity; but, contrary to all experience and reason, he supposed that these cooling rings kept contracting and widening out from the heated ma.s.s, at the same time. The only fluid planetary rings which we can examine--those of Saturn--have been closing in on the planet since the days of Huygens, and eventually will be united with the body of the planet. Every boy who has seen a blacksmith hoop a cart-wheel has learned the principle, that a heated ring contracts as it cools, and in doing so presses in upon the ma.s.s around which it clings. But, according to this nebular notion, the fire-mist keeps cooling and shrinking up, while the rings, of the very same heat and material, keep cooling faster, and widening out from it; a piece of schismatical behavior without a parallel among solids or fluids, either in heaven or earth, or under the earth.

Plateau's ill.u.s.tration of the mode in which centrifugal force acts in overcoming molecular attraction, has been cited as a demonstration of the truth of the nebular hypothesis. The conditions, however, are entirely different. By means of clock-work he caused a globule of oil to rotate in a mixture of alcohol and water _of the same density_, thus entirely getting rid of the power of gravitation; and by increasing the velocity he caused it to flatten out into a disc, and finally to project a mult.i.tude of minute drops, which continued their revolutions so long as the fluid in which they floated kept revolving by the motion of the rotating spindle, _the divergent drops, the central ma.s.s, and the surrounding fluid, being all the while of the same density_. But the essential conditions of the nebular theory are, that _the central ma.s.s_ exert an attraction of gravitation upon all its parts, and _therefore be denser than the surrounding ether or empty s.p.a.ce_, and that _the cooling and contracting rings be of a different density from the rest of the ma.s.s_. Their divergence from the more fluid portion is supposed to arise from their growing denser. And Reclus shows[204] that the divergent drops owe their existence to the _expansion_, not to the _contraction_, of the globule of oil. This experiment, then, contradicts the theory, so far as it is applicable.

Plateau himself never adduced this experiment in support of the nebular theory; but having, by way of ill.u.s.tration, spoken of the revolving drops as satellites, and finding that expression misunderstood, he corrected the error in a subsequent paper. He says: "It is clear that this mode of formation is entirely foreign to La Place's cosmogonic hypothesis; therefore we have no idea of deducing from this little experiment, which only refers _to the effects of molecular attraction_, and _not to those of gravitation_, any argument in favor of the hypothesis in question; an hypothesis which _in other respects we do not adopt_."[205]

_It was always contrary to the facts of astronomical science._ It has accordingly been repudiated by the most eminent astronomers.

Sir John Herschel declares that the appearance of those groups, or cl.u.s.ters, of stars, supposed to be formed by the condensation of nebulae is quite different from that depicted by this theory, and that no traces of the ring-making process is visible among them. He thus describes the appearances of these groups; exactly the contrary of that demanded by the theory, which he emphatically disclaims, from the presidential chair of the British a.s.sociation for the Advancement of Science.

"If it is to be regarded as demonstrated truth, or as receiving the smallest support from any observed numerical relations which actually hold good among the elements of the primary orbits, I beg leave to demur. a.s.suredly it receives no support from the observation of the effects of sidereal aggregation as exemplified in the formation of globular and elliptic cl.u.s.ters, supposing them to have resulted from such aggregation. For we see this cause working out in thousands of instances, to have resulted, _not_ in the formation of a single large central body, surrounded by a few smaller attendants disposed in one plane around it, but in systems of infinitely greater complexity, consisting of mult.i.tudes of nearly equal luminaries, grouped together in a solid elliptic or globular form. So far then as any conclusions from our observations of nebulae can go, the result of agglomerative tendencies _may_ indeed be the formation of families of stars of a general and very striking character, but we see nothing to lead us to presume its further result to be the surrounding of those stars with planetary adherents."[206]

_This theory is contradicted by the peculiarities of our solar system._ The orbits of the comets being inclined at all angles to the sun's equator, are often out of the plane of his rotation, and so in the way of the theory. The moons of Ura.n.u.s revolve in a direction contrary to all the other bodies, and fly right into the face of the theory.

According to the nebular theory, the outer planets, first cast off from the sun, ought to be lighter than those nearer him, as these had longer pressing near the middle of the ma.s.s; and the sun himself, having been pressed by the weight of all the rest of the system, should be the densest body of the whole. And the author of _The Vestiges of Creation_, in expounding the theory, manufactures a set of facts to suit it, and tells his readers that the planets exhibit a progressive diminution in density from the one nearest the sun to that which is most distant. Our solar system could not have lasted thirty years had that been the case.

The Earth, Venus, and Mars, are nearly of the same density. Ura.n.u.s is more dense than Saturn, which is nearer the sun. Neptune is more dense than either. The sun, which ought to be the heaviest of all, according to the theory, is only one-fourth the density of the earth. La Place himself has demonstrated that these densities and arrangements are indispensable to the stability of the system. But they are plainly contradictory to his theory of its formation.[207]

The palpable difference of luminosity between the sun and the planets, which, as they are all made of the very same materials, and by the same process, according to this theory, ought to be equally self-luminous, is in itself a self-evident refutation of the nebular hypothesis, or of any other process of creation by mere mechanical law. "The same power, whether natural or supernatural, which placed the sun in the center of the six primary planets, placed Saturn in the center of the orb of his five secondary planets; and Jupiter in the center of his four secondary planets; and the earth in the center of the moon's...o...b..t; and, therefore, had this cause been a blind one, _without contrivance or design_, the sun would have been a body of the same kind with Saturn, Jupiter, and the Earth; that is, _without light or heat_. Why there is one body in our system qualified to give light and heat to all the rest, I know no reason, but because the Author of the system thought it convenient." So says the immortal Newton.[208]

The great expounder of modern science--Humboldt--is equally explicit in enumerating the decisive marks of choice and will in the construction of the solar system, and in contemptuously dismissing the notion of development and creation by natural law from the halls of science.

"Up to the present time, _we are ignorant, as I have already remarked, of any internal necessity--any mechanical law of nature_--which (like the beautiful law which connects the square of the periods of revolution with the cube of the major axis) represents the above-named elements--the absolute magnitude of the planets, their density, flattening at the poles, velocity of rotation, and presence or absence of moons--of the order of succession of the individual planetary bodies of each group, in their dependence upon the distances. Although the planet which is nearest the sun is densest--even six or eight times denser than some of the exterior planets: Jupiter, Saturn, Ura.n.u.s, and Neptune--the order of succession in the case of Venus, the Earth, and Mars, is very irregular. The absolute magnitudes do, generally, as Kepler has already observed, increase with the distances; but this does not hold good when the planets are considered individually. Mars is smaller than the Earth; Ura.n.u.s smaller than Saturn; Saturn smaller than Jupiter, and succeeds immediately to a host of planets, which, on account of their smallness, are almost immeasurable. It is true, the period of rotation generally increases with the distance from the sun; but it is in the case of Mars slower than in that of the Earth, and slower in Saturn than in Jupiter."[209] "_Our knowledge of the primeval ages of the world's physical history does not extend sufficiently far to allow of our depicting the present condition of things as one of development._"[210]

Sir David Brewster adds his testimony as follows: "Geology does not pretend to give us any information respecting the process by which the nucleus of the earth was formed. Some speculative astronomers indeed have presumptuously embarked in such an inquiry; but there is not a trace of evidence that the solid nucleus of the globe was formed by secondary causes, such as the aggregation of attenuated matter diffused through s.p.a.ce; and the _nebular theory_, as it has been called, though maintained by a few distinguished names, has, we think, been overturned by arguments which have never been answered. Sir Isaac Newton, in his four celebrated letters to Dr. Bentley, has demonstrated that the planets of the solar system could not have been thus formed and put in motion round a central sun."[211]

4. _Astronomy not only exposes the folly of past cosmogonies, but demonstrates the impossibility of framing any true theory of creation, and thus refutes all future cosmogonies._