In his intercourse with spirits from Jupiter, Swedenborg heard of animals larger than those that live on the earth. It has been a favourite idea of many believers in other worlds than ours, that though in each world the same races of animals exist, they would be differently proportioned; and there has been much speculation as to the probable size of men and other animals in worlds much larger or much smaller than the earth. When as yet ideas about other worlds were crude, the idea prevailed that giants exist in the larger orbs, and pygmies in the smaller. Whether this idea had its origin in conceptions as to the eternal fitness of things or not, does not clearly appear. It seems certainly at first view natural enough to suppose that the larger beings would want more room and so inhabit the larger dwelling-places. It was a pleasing thought that, if we could visit Jupiter or Saturn, we should find the human inhabitants there
In bigness to surpa.s.s earth"s giant sons;
but that if we could visit our moon or Mercury, or whatever smaller worlds there are, we should find men
Now less than smallest dwarfs, in narrow room Throng numberless, like that pygmaean race Beyond the Indian mount; or fairy elves, Whose midnight revels, by a forest side Or fountain, some belated peasant sees, Or dreams he sees.
Later the theory was started that the size of beings in various worlds depends on the amount of light received from the central sun. Thus Wolfius a.s.serted that the inhabitants of Jupiter are nearly fourteen feet high, which he proved by comparing the quant.i.ty of sunlight which reaches the Jovians with that which we Terrenes receive. Recently, however, it has been noted that the larger the planet, the smaller in all probability must be the inhabitants, if any. For if there are two planets of the same density but unequal size, gravity must be greater at the surface of the larger planet, and where gravity is great large animals are c.u.mbered by their weight. It is easy to see this by comparing the muscular strength of two men similarly proportioned, but unequal in height. Suppose one man five feet in height, the other six; then the cross section of any given muscle will be less for the former than for the latter in the proportion of twenty-five (five times five) to thirty-six (six times six). Roughly, the muscular strength of the bigger man will be half as great again as that of the smaller. But the weights of the men will be proportioned as 125 (five times five times five) to 216 (six times six times six), so that the weight of the bigger man exceeds that of the smaller nearly as seven exceeds four, or by three-fourths. The taller man exceeds the smaller, then, much more in weight than he does in strength; he is accordingly less active in proportion to his size. Within certain limits, of course, size increases a man"s effective as well as his real strength. For instance, our tall man in the preceding ill.u.s.tration cannot lift his own weight as readily as the small man can lift his; but he can lift a weight of three hundred pounds as easily as the small man can lift a weight of two hundred pounds. When we get beyond certain limits of height, however, we get absolute weakness as the result of the increase of weight. Swift"s Brobdingnags, for instance, would have been unable to stand upright; for they were six times as tall as men, and therefore each Brobdingnag would have weighed 216 times as much as a man, but would have possessed only thirty-six times the muscular power. Their weight would have been greater, then, in a sixfold greater degree than their strength, and, so far as their mere weight was concerned, their condition would have resembled that of an ordinary man under a load five times exceeding his own weight. As no man could walk or stand upright under such a load, so the Brobdingnags would have been powerless to move, despite, or rather because of, their enormous stature. Applying the general considerations here enunciated to the question of the probable size of creatures like ourselves in other planets, we see that men in Jupiter should be much smaller, men in Mercury much larger, than men on the earth. So also with other animals.
But Swedenborg"s spirit visitors from these planets taught differently.
"The horses of our earth," he says, "when seen by the spirits of Jupiter, appeared to me smaller than usual, though rather robust; which arose from the idea those spirits had respecting them. They informed me that among them there are animals similar, though much larger; but that they are wild, and in the woods, and that when they come in sight they cause terror though they are harmless; they added that their terror of them is natural or innate."[28] On the other hand the inhabitants of Mercury, who might be thirteen feet high yet as active as our men, appeared slenderer than Terrene men. "I was desirous to know," says Swedenborg, "what kind of face and person the people in Mercury have, compared with those of the people on our earth. There therefore stood before me a female exactly resembling the women on that earth. Her face was beautiful, but it was smaller than that of a woman of our earth; she was more slender, but of equal height; she wore a linen head-dress, not artfully yet gracefully disposed. A man also was presented. He, too, was more slender than the men of our earth; he wore a garment of deep blue, closely fitted to his body without folds or flowing skirts. Such, I learn, were the personal form and costume of the humans of that earth.
Afterwards there was shown me a species of the oxen and cows, which did not indeed differ much from those on our earth, except that they were smaller, and made some approach to the stag and hind species." We have seen, too, that the lunar spirits were no larger than children seven years old.
One pa.s.sage of Swedenborg"s description of Jupiter is curious. "Although on that earth," he says, "spirits speak with men" (_i.e._ with Jovian men) "man in his turn does not speak with spirits, except to say, when instructed, _that he will do so no more_,"--which we should regard as a bull if it were not news from the Jovian spirit world. "Nor is man allowed to tell anyone that a spirit has spoken to him; if he does so, he is punished. Those spirits of Jupiter when they were with me, at first supposed they were with a man of their own earth; but when in my turn I spoke with them, and thought of publishing what pa.s.sed between us and so relating it to others, then, because they were not allowed to chastise me, they discovered they were with a stranger."
It has been a favourite idea with those who delight in the argument from design, that the moons of the remoter planets have been provided for the express purpose of making up for the small amount of sunlight which reaches those planets. Jupiter receives only about one twenty-seventh part of the light which we receive from the sun; but then, has he not four moons to make his nights glorious? Saturn is yet farther away from the sun, and receives only the ninetieth part of the light we get from the sun; but then he has eight moons and his rings, and the nocturnal glory of his skies must go far to compensate the Saturnians for the small quant.i.ty of sunlight they receive. The Saturnian spirits who visited Swedenborg were manifestly indoctrinated with these ideas. For they informed him that the nocturnal light of Saturn is so great that some Saturnians worship it, calling it the Lord. These wicked spirits are separated from the rest, and are not tolerated by them. "The nocturnal light," say the spirits, "comes from the immense ring which at a distance encircles that earth, and from the moons which are called the satellites of Saturn." And again, being questioned further "concerning the great ring which appears from our earth to rise above the horizon of that planet, and to vary its situations, they said that it does not appear to them as a ring, but only as a snow-white substance in heaven in various directions." Unfortunately for our faith in the veracity of these spirits, it is certain that the moons of Saturn cannot give nearly so much light as ours, while the rings are much more effective as darkeners than as illuminators. One can readily calculate the apparent size of each of the moons as seen from Saturn, and thence show that the eight discs of the moons together are larger than our moon"s disc in about the proportion of forty-five to eight. So that if they were all shining as brightly as our full moon and all full at the same time, their combined light would exceed hers in that degree. But they are not illuminated as our moon is. They are illuminated by the same remote sun which illuminates Saturn, while our moon is illuminated by a sun giving her as much light as we ourselves receive. Our moon then is illuminated ninety times more brightly than the moons of Saturn, and as her disc is less than all theirs together, not as one to ninety, but as sixteen to ninety, it follows that all the Saturnian moons, if full at the same time, would reflect to Saturn one-sixteenth part of the light which we receive from the full moon.[29] As regards the rings of Saturn, nothing can be more certain than that they tend much more to deprive Saturn of light then to make up by reflection for the small amount of light which Saturn receives directly from the sun. The part of the ring which lies between the planet and the sun casts a black shadow upon Saturn, this shadow sometimes covering an extent of surface many times exceeding the entire surface of our earth. The shadow thus thrown upon the planet creeps slowly, first one way, then another, northwards and southwards over the illuminated hemisphere of the planet (as pictured in the 13th plate of my treatise on Saturn), requiring for its pa.s.sage from the arctic to the antarctic regions and back again to the arctic regions of the planet, a period nearly equal to that of a generation of terrestrial men. Nearly thirty of our years the process lasts, during half of which time the northern hemisphere suffers, and during the other half the southern. The shadow band, which be it remembered stretches right athwart the planet from the extreme eastern to the extreme western side of the illuminated hemisphere, is so broad during the greater part of the time that in some regions (those corresponding to our temperate zones) the shadow takes two years in pa.s.sing, during which time the sun cannot be seen at all, unless for a few moments through some c.h.i.n.ks in the rings, which are known to be not solid bodies, but made up of closely crowded small moons. And the slow pa.s.sage of this fearful shadow, which advances at the average rate of some twenty miles a day, but yet hangs for years over the regions athwart which it sweeps, occurs in the very season when the sun"s small direct supply of heat would require to be most freely compensated by nocturnal light--in the winter season, namely, of the planet. Moreover, not only during the time of the shadow"s pa.s.sage, but during the entire winter half of the Saturnian year, the ring reflects no light during the night time, the sun being on the other or summer side of the ring"s plane.[30] The only nocturnal effect which would be observable would be the obliteration of the stars covered by the ring system. It is strange that, this being so, the spirits from Saturn should have made no mention of the circ.u.mstance; and even more strange that these spirits and others should have a.s.serted that the moons and rings of Saturn compensate for the small amount of light directly received from the sun. Most certainly a Swedenborg of our own time would find the spirits from Saturn more veracious and more communicative about these matters, though even what _he_ would hear from the spirits would doubtless appear to sceptics of the twenty-first century to be no more than he could have inferred from the known facts of the science of his day.
But Swedenborg was not content merely to receive visits from the inhabitants of other planets in the solar system. He was visited also by the spirits of earths in the starry heaven; nay, he was enabled to visit those earths himself. For man, even while living in the world, "is a spirit as to his interiors, the body which he carries about in the world only serving him for performing functions in this natural or terrestrial sphere, which is the lowest." And to certain men it is granted not only to converse as a spirit with angels and spirits, but to traverse in a spiritual way the vast distances which separate world from world and system from system, all the while remaining in the body. Swedenborg was one of these. "The interiors of my spirit," he says, "are opened by the Lord, so that while I am in the body I can at the same time be with angels in heaven, and not only converse with them, but behold the wonderful things which are there and describe them, that henceforth it may no more be said, "Who ever came from heaven to a.s.sure us it exists and tell us what is there?" He who is unacquainted with the arcana of heaven cannot believe that man can see earths so remote, and give any account of them from sensible experience. But let him know that s.p.a.ces and distances, and consequently progressions, existing in the natural world, in their origin and first causes are changes of the state of the interiors; that with angels and spirits progressions appear according to changes of state; and that by changes of state they may be apparently translated from one place to another, and from one earth to another, even to earths at the boundaries of the universe; so likewise may man as to his spirit, his body still remaining in its place. This has been the case with me."
Before describing his visits to earths in the starry heavens, Swedenborg is careful to indicate the probability that such earths exist. "It is well known to the learned world," he says, "that every star is a sun in its place, remaining fixed like the sun of our earth." The proper motions of the stars had, alas! not been discovered in Swedenborg"s day, nor does he seem to have been aware what a wild chase he was really entering upon in his spiritual progressions. Conceive the pursuit of Sirius or Vega as either sun rushed through s.p.a.ce with a velocity of thirty or forty miles in every second of time! To resume, however, the account which Swedenborg gives of the ideas of the learned world of his day. "It is the distance which makes a star appear in a small form; consequently" (the logical necessity is not manifest, however) "each star, like the sun of our system, has around it planets which are earths; and the reason these are not visible to us is because of their immense distance and their having no light but from their own star, which light cannot be reflected so far as to reach us." "To what other end," proceeds this most convincing reasoning, "can be so immense a heaven with such a mult.i.tude of stars? For man is the end for which the universe was created. It has been ascertained by calculation that supposing there were in the universe a million earths, and on every earth three hundred millions of men and two hundred generations within six thousand years, and that to every man or spirit was allotted a s.p.a.ce of three cubic ells, the collective number of men or spirits could not occupy a s.p.a.ce equal to a thousandth part of this earth, thus not more than that occupied by one of the satellites of Jupiter or Saturn; a s.p.a.ce on the universe almost undiscernible, for a satellite is hardly visible to the naked eye. What would this be for the Creator of the universe, to whom the whole universe filled with earths could not be enough" (for what?), "seeing that he is infinite." However, it is not on this reasoning alone that Swedenborg relies. He tells us, honestly beyond all doubt, that he knows the truth of what he relates. "The information I am about to give," he says, "respecting the earths in the starry heaven is from experimental testimony; from which it will likewise appear how I was translated thither as to my spirit, the body remaining in its place."
His progress in his first star-hunt was to the right, and continued for about two hours. He found the boundary of our solar system marked first by a white but thick cloud, next by a fiery smoke ascending from a great chasm. Here some guards appeared, who stopped some of the company, because these had not, like Swedenborg and the rest, received permission to pa.s.s. They not only stopped those unfortunates, but tortured them, conduct for which terrestrial a.n.a.logues might possibly be discovered.
Having reached another system, he asked the spirits of one of the earths there how large their sun was and how it appeared. They said it was less than the sun of our earth, and has a flaming appearance. Our sun, in fact, is larger than other suns in s.p.a.ce, for from that earth starry heavens are seen, and a star larger than the rest appears, which, say those spirits, "was declared from heaven" to be the sun of Swedenborg"s earthly home.
What Swedenborg saw upon that earth has no special interest. The men there, though haughty, are loved by their respective wives because they, the men, are good. But their goodness does not appear very manifest from anything in the narrative. The only man seen by Swedenborg took from his wife "the garment which she wore, and threw it over his own shoulders; loosening the lower part, which flowed down to his feet like a robe (much as a man of our earth might be expected to loosen the tie-back of the period, if he borrowed it in like manner) he thus walked about clad."
He next visited an earth circling round a star, which he learned was one of the smaller sort, not far from the equator. Its greater distance was plain from the circ.u.mstance that Swedenborg was two days in reaching it.
In this earth he very nearly fell into a quarrel with the spirits. For hearing that they possess remarkable keenness of vision, he "compared them with eagles which fly aloft, and enjoy a clear and extensive view of objects beneath." At this they were indignant, supposing, poor spirits, "that he compared them to eagles as to their rapacity, and consequently thought them wicked." He hastened to explain, however, that he "did not liken them to eagles as to their rapacity, but as to sharpsightedness."
Swedenborg"s account of a third earth in the star-depths contains a very pretty idea for temples and churches. The temples in that earth "are constructed," he says, of trees, not cut down, but growing in the place where they were first planted. On that earth, it seems, there are trees of an extraordinary size and height; these they set in rows when young, and arrange in such an order that they may serve when they grow up to form porticoes and colonnades. In the meanwhile, by cutting and pruning, they fit and prepare the tender shoots to entwine one with another, and join together so as to form the groundwork and floor of the temple to be constructed, and to rise at the sides as walls, and above to bend into arches to form the roof. In this manner they construct the temple with admirable art, elevating it high above the ground. They prepare also an ascent into it, by continuous branches of the trees, extended from the trunk and firmly connected together. Moreover, they adorn the temple without and within in various ways, by disposing the foliage into particular forms; thus they build entire groves. But it was not permitted me to see the nature of these temples, only I was informed that the light of their sun is let in by apertures amongst the branches, and is everywhere transmitted through crystals; whereby the light falling on the walls is refracted in colours like those of the rainbow, particularly blue and orange, of which they are fondest. Such is their architecture, which they prefer to the most magnificent palaces of our earth."
Other earths in the starry heavens were visited by Swedenborg, but the above will serve sufficiently to ill.u.s.trate the nature of his observations. One statement, by the way, was made to him which must have seemed unlikely ever to be contravened, but which has been shown in our time to be altogether erroneous. In the fourth star-world he visited, he was told that that earth, which travels round its sun in 200 days of fifteen hours each, is one of the least in the universe, being scarcely 500 German miles, say 2000 English miles, in circ.u.mference. This would make its diameter about 640 English miles. But there is not one of the whole family of planetoids which has a diameter so great as this, and many of these earths must be less than fifty miles in diameter. Now Swedenborg remarks that he had his information from the angels, "who made a comparison in all these particulars with things of a like nature on our earth, according to what they saw in me or in my memory. Their conclusions were formed by angelic ideas, whereby are instantly known the measure of s.p.a.ce and time in a just proportion with respect to s.p.a.ce and time elsewhere. Angelic ideas, which are spiritual, in such calculations infinitely excel human ideas, which are natural." He must therefore have met, unfortunately, with untruthful angels.
The real source of Swedenborg"s inspirations will be tolerably obvious--to all, at least, who are not Swedenborgians. But our account of his visions would not be complete in a psychological sense without a brief reference to the personal allusions which the spirits and angels made during their visits or his wanderings. His distinguished rival, Christian Wolf, was encountered as a spirit by spirits from Mercury, who "perceived that what he said did not rise above the sensual things of the natural man, because in speaking he thought of honour, and was desirous, as in the world (for in the other world every one is like his former self), to connect various things into series, and from these again continually to deduce others, and so form several chains of such, which they did not see or acknowledge to be true, and which, therefore, they declared to be chains which neither cohered in themselves nor with the conclusions, calling them the obscurity of authority;" so they ceased to question him further, and presently left him. Similarly, a spirit who in this world had been a "prelate and a preacher," and "very pathetic, so that he could deeply move his hearers," got no hearing among the spirits of a certain earth in the starry heavens; for they said they could tell "from the tone of the voice whether a discourse came from the heart or not;" and as his discourse came not from the heart, "he was unable to teach them, whereupon he was silent."
Convenient thus to have spirits and angels to confirm our impressions of other men, living or dead.
Apart from the psychological interest attaching to Swedenborg"s strange vision, one cannot but be strongly impressed by the idea pervading them, that to beings suitably const.i.tuted all that takes place in other worlds might be known. Modern science recognises a truth here; for in that mysterious ether which occupies all s.p.a.ce, messages are at all times travelling by which the history of every orb is constantly recorded. No world, however remote or insignificant; no period, however distant--but has its history thus continually proclaimed in ever widening waves. Nay, by these waves also (to beings who could read their teachings aright) the future is constantly indicated. For, as the waves which permeate the ether could only be situated as they actually are, at any moment, through past processes, each one of which is consequently indicated by those ethereal waves, so also there can be but one series of events in the future, as the sequel of the relations actually indicated by the ethereal undulations. These, therefore, speak as definitely and distinctly of the future as of the past. Could we but rid us of the gross habiliments of flesh, and by some new senses be enabled to feel each order of ethereal undulations, even of those only which reach our earth, all knowledge of the past and future would be within our power.
The consciousness of this underlies the fancies of Swedenborg, just as it underlies the thought of him who sang--
There"s not an orb which thou behold"st But in his motion like an angel sings, Still quiring to the young-eyed cherubim.
But while this muddy vesture of decay Doth grossly close us in, we cannot hear it.
V.
_OTHER WORLDS AND OTHER UNIVERSES._
If any one shall gravely tell me that I have spent my time idly in a vain and fruitless inquiry after what I can never become sure of, the answer is that at this rate he would put down all natural philosophy, as far as it concerns itself in searching into the nature of such things. In such n.o.ble and sublime studies as these, "tis a glory to arrive at probability, and the search itself rewards the pains. But there are many degrees of probable, some nearer to the truth than others, in the determining of which lies the chief exercise of our judgment. And besides the n.o.bleness and pleasure of the studies, may we not be so bold as to say that they are no small help to the advancement of wisdom and morality?--HUYGHENS, _Conjectures concerning the Planetary Worlds_.
The interest with which astronomy is studied by many who care little or nothing for other sciences is due chiefly to the thoughts which the celestial bodies suggest respecting life in other worlds than ours.
There is no feeling more deeply seated in the human heart--not the belief in higher than human powers, not the hope of immortality, not even the fear of death--than the faith in realms of life where other conditions are experienced than those we are acquainted with here. It is not vulgar curiosity or idle fancy that suggests the possibilities of life in other worlds. It has been the conviction of the profoundest thinkers, of men of highest imagination. The mystery of the star-depths has had its charm for the mathematician as well as for the poet; for the exact observer as for the most fruitful theoriser; nay, for the man of business as for him whose life is pa.s.sed in communing with nature. If we a.n.a.lyse the interest with which the generality of men inquire into astronomical matters apparently not connected with the question of life in other worlds, we find in every case that it has been out of this question alone or chiefly that that interest has sprung. The great discoveries made during the last few years respecting the sun for example, might seem remote from the subject of life in other worlds. It is true that Sir William Herschel thought the sun might be the abode of living creatures; and Sir John Herschel even suggested the possibility that the vast streaks of light called the solar willow-leaves, objects varying from two hundred to a thousand miles in length, might be living creatures whose intense l.u.s.tre was the measure of their intense vitality. But modern discoveries had rendered all such theories untenable. The sun is presented to us as a mighty furnace, in whose fires the most stubborn elements are not merely melted but vaporised.
The material of the sun has been a.n.a.lysed, the motions and changes taking place on his surface examined, the laws of his being determined.
How, it might be asked, is the question of life in other worlds involved in these researches? The faith of Sir David Brewster in the sun as the abode of life being dispelled, how could discoveries respecting the sun interest those who care about the subject of the plurality of worlds?
The answer to these questions is easily found. The real interest which solar researches have possessed for those who are not astronomers has resided in the evidence afforded respecting the sun"s position as the fire, light, and life of the system of worlds whereof our world is one.
The mere facts discovered respecting the sun would be regarded as so much dry detail were they not brought directly into relation with our earth and its wants, and therefore with the wants of the other earths which circle round the sun; but when thus dealt with they immediately excite attention and interest. I do not speak at random in a.s.serting this, but describe the result of widely ranging observation. I have addressed hundreds of audiences in Great Britain and America on the subject of recent solar discoveries, and I have conversed with many hundreds of persons of various capacity and education, from men almost uncultured to men of the highest intellectual power; and my invariable experience has been that solar research derives its chief interest when viewed in relation to the sun"s position as the mighty ruler, the steadfast sustainer, the beneficent almoner of the system of worlds to which our earth belongs. It is the same with other astronomical subjects. Few care for the record of lunar observations, save in relation to the question whether the moon is or has been the abode of living creatures. The movements of comets and meteors, and the discoveries recently made respecting their condition, have no interest except in relation to the position of these bodies in the economy of solar systems, or to the possible part which they may at one time have performed in building up worlds and suns. None save astronomers, and few only of these, care for researches into the star-depths, except in connection with the thought that every star is a sun and therefore probably the light and fire of a system of worlds like those which circle around our own sun.
It is singular how variously this question of life in other worlds has been viewed at various stages of astronomical progress. From the time of Pythagoras, who first, so far as is known, propounded the general theory of the plurality of worlds, down to our own time, when Brewster and Chalmers on the one hand, and Whewell on the other, have advocated rival theories probably to be both set aside for a theory at once intermediate to and more widely ranging in time and s.p.a.ce than either, the aspect of the subject has constantly varied, as new lights have been thrown upon it from different directions. It may be interesting briefly to consider what has been thought in the past on this strangely attractive question, and then to indicate the view towards which modern discoveries seem manifestly to point--a view not likely to undergo other change than that resulting from clearer vision and closer approach. In other words, I shall endeavour to show that the theory to which we are now led by all the known facts is correct in general, though, as fresh knowledge is obtained, it may undergo modification in details. We now see the subject from the right point of view, though as science progresses we may come to see it more clearly and definedly.
When men believed the earth to be a flat surface above which the heavens were arched as a tent or canopy, they were not likely to entertain the belief in other worlds than ours. During the earlier ages of mankind ideas such as these prevailed. The earth had been fashioned into its present form and condition, the heavens had been spread over it, the sun, and moon, and stars had been set in the heavens for its use and adornment, and there was no thought of any other world.
But while this was the general belief, there was already a school of philosophy where another doctrine had been taught. Pythagoras had adopted the belief of Apollonius Pergaeus that the sun is the centre of the planetary paths, the earth one among the planets--a belief inseparable from the doctrine of the plurality of worlds. Much argument has been advanced to show that this belief never was adopted before the time of Copernicus, and unquestionably it must be admitted that the theory was not presented in the clear and simple form to which we have become accustomed. But it is not necessary to weigh the conflicting arguments for and against the opinion that Pythagoras and others regarded the earth as not the fixed centre of the universe. The certain fact that the doctrine of the plurality of worlds was entertained (I do not say adopted) by them, proves sufficiently that they cannot have believed the earth to be fixed and central. The idea of other worlds like our earth is manifestly inconsistent with the belief that the earth is the central body around which the whole universe revolves.
That this is so is well ill.u.s.trated by the fate of the unfortunate Giordano Bruno. He was one of the first disciples of Copernicus, and, having accepted the doctrine that the earth travels round the sun as one among his family of planets, was led very naturally to the belief that the other planets are inhabited. He went farther, and maintained that as the earth is not the only inhabited world in the solar system, so the sun is not the only centre of a system of inhabited worlds, but each star a sun like him, about which many planets revolve. This was one of the many heresies for which Bruno was burned at the stake. It is easy, also, to recognise in the doctrine of many worlds as the natural sequel of the Copernican theory, rather than in the features of this theory itself, the cause of the hostility with which theologians regarded it, until, finding it proved, they discovered that it is directly taught in the books which they interpret for us so variously. The Copernican theory was not rejected--nay, it was even countenanced--until this particular consequence of the theory was recognised. But within a few years from the persecution of Bruno, Galileo was imprisoned, and the last years of his life made miserable, because it had become clear that in setting the earth adrift from its position as centre of the universe, he and his brother Copernicans were sanctioning the belief in other worlds than ours. Again and again, in the attacks made by clericals and theologians upon the Copernican theory, this lamentable consequence was insisted upon. Unconscious that they were advancing the most damaging argument which could be conceived for the cause they had at heart, they maintained, honestly but unfortunately, that with the new theory came the manifest inference that our earth is not the only and by no means the most important world in the universe--a doctrine manifestly inconsistent (so they said) with the teachings of the Scriptures.
It was naturally only by a slow progression that men were able to advance into the domain spread before them by the Copernican theory, and to recognise the real minuteness of the earth both in s.p.a.ce and time.
They more quickly recognised the earth"s insignificance in s.p.a.ce, because the new theory absolutely forced this fact upon them. If the earth, whose globe they knew to be minute compared with her distance from the sun, is really circling around the sun in a mighty orbit many millions of miles in diameter, it follows of necessity that the fixed stars must lie so far away that even the span of the earth"s...o...b..t is reduced to nothing by comparison with the vast depths beyond which lie even the nearest of those suns. This was Tycho Brahe"s famous and perfectly sound argument against the Copernican theory. "The stars remain fixed in apparent position all the time, yet the Copernicans tell us that the earth from which we view the stars is circling once a year in an orbit many millions of miles in diameter; how is it that from so widely ranging a point of view we do not see widely different celestial scenery? Who can believe that the stars are so remote that by comparison the span of the earth"s path is a mere point?" Tycho"s argument was of course valid.[31] Of two things one. Either the earth does not travel round the sun, or the stars are much farther away than men had conceived possible in Tycho"s time. His mistake lay in rejecting the correct conclusion because simply it made the visible universe seem many millions of times vaster than he had supposed. Yet the universe, even as thus enlarged, was but a point to the universe visible in our day, which in turn will dwindle to a point compared with the universe as men will see it a few centuries hence; while that or the utmost range of s.p.a.ce over which men can ever extend their survey is doubtless as nothing to the real universe of occupied s.p.a.ce.
Such has been the progression of our ideas as to the position of the earth in s.p.a.ce. Forced by the discoveries of Copernicus to regard our earth as a mere point compared with the distances of the nearest fixed stars, men gradually learned to recognise those distances which at first had seemed infinite as in their turn evanescent even by comparison with that mere point of s.p.a.ce over which man is able by instrumental means to extend his survey.
Though there has been a similar progression in men"s ideas as to the earth"s position in time, that progression has not been carried to a corresponding extent. Men have not been so bold in widening their conceptions of time as in widening their conceptions of s.p.a.ce. It is here and thus that, in my judgment, the subject of life in other worlds has been hitherto incorrectly dealt with. Men have given up as utterly idle the idea that the existence of worlds is to be limited to the special domain of s.p.a.ce to which our earth belongs; but they are content to retain the conception that the domain of time to which our earth"s history belongs, "this bank and shoal of time" on which the life of the earth is cast, is the period to which the existence of other worlds than ours should be referred.
This, which is to be noticed in nearly all our ordinary treatises on astronomy, appears as a characteristic peculiarity of works advocating the theory of the plurality of worlds. Brewster and d.i.c.k and Chalmers, all in fact who have taken that doctrine under their special protection, reason respecting other worlds as though, if they failed to prove that other orbs are inhabited _now_, or are at least _now_ supporting life in some way or other, they failed of their purpose altogether. The idea does not seem to have occurred to them that there is room and verge enough in eternity of time not only for activity but for rest. They must have all the orbs of s.p.a.ce busy at once in the one work which they seem able to conceive as the possible purpose of those bodies--the support of life. The argument from a.n.a.logy, which they had found effective in establishing the general theory of the plurality of worlds, is forgotten when its application to details would suggest that not _all_ orbs are _at all times_ either the abode of life or in some way subserving the purposes of life.
We find, in all the forms of life with which we are acquainted, three characteristic periods--first the time of preparation for the purposes of life; next, the time of fitness for those purposes; and thirdly, the time of decadence tending gradually to death. We see among all objects which exist in numbers, examples of all these stages existing at the same time. In every race of living creatures there are the young as yet unfit for work, the workers, and those past work; in every forest there are saplings, seed-bearing trees, and trees long past the seed-bearing period. We know that planets, or rather, speaking more generally, the orbs which people s.p.a.ce, pa.s.s through various stages of development, during some only of which they can reasonably be regarded as the abode of life or supporting life; yet the eager champion of the theory of many worlds will have them all in these life-bearing or life-supporting stages, none in any of the stages of preparation, none in any of the stages of decrepitude or death.
This has probably had its origin in no small degree from the disfavour with which in former years the theory of the growth and development of planets and systems of planets was regarded. Until the evidence became too strong to be resisted, the doctrine that our earth was once a baby world, with many millions of years to pa.s.s through before it could be the abode of life, was one which only the professed atheist (so said too many divines) could for a moment entertain; while the doctrine that not the earth alone, but the whole of the solar system, had developed from a condition utterly unlike that through which it is now pa.s.sing, could have had its origin only in the suggestions of the Evil One. Both doctrines were p.r.o.nounced to be so manifestly opposed to the teachings of Moses, and not only so, but so manifestly inconsistent with the belief in a Supreme Being, that--that further argument was unnecessary, and denunciation only was required. So confident were divines on these points, that it would not have been very wonderful if some few students of science had mistaken a.s.sertion for proof, and so concluded that the doctrines towards which science was unmistakably leading them really were inconsistent with what they had been taught to regard as the Word of G.o.d. Whether multiplied experiences taught men of science to wait before thus deciding, or however matters fell out, it certainly befell before very long that the terrible doctrine of cosmical development was supported by such powerful evidence, astronomical and terrestrial, as to appear wholly irresistible. Then, not only was the doctrine accepted by divines, but shown to be manifestly implied in the sacred narrative of the formation of the earth and heavens, sun, and moon, and stars; while upon those unfortunate students of science who had not changed front in good time, and were found still arguing on the mistaken a.s.sumption that the development of our system was not accordant with that ancient narrative, freshly forged bolts were flung from the Olympus of orthodoxy.
So far as the other argument--from the inconsistency of the development theory with belief in a Supreme Being--was concerned, the student of science was independent of the interpretations which divines claim the sole right of a.s.signing to the ancient books. Science has done so much more than divinity (which in fact has done nothing) to widen our conceptions of s.p.a.ce and time, that she may justly claim full right to deal with any difficulties arising from such enlargement of our ideas.
With the theological difficulty science would not care to deal at all, were she not urged to do so by the denunciations of divines; and when, so urged, she touches that difficulty, she is quickly told that the difficulty is insuperable, and not long after that it has no existence, and (on both accounts) that it should have been left alone. But with the difficulty arising from the widening of our ideas respecting s.p.a.ce and time, science may claim good, almost sole, right to deal. The path to a solution of the problem is not difficult to find. At a first view, it does seem to those whose vision had been limited to a contracted field, that the wide domain of time and s.p.a.ce in which processes of development are found to take place is the universe itself, that to deny the formation of our earth by a special creative act is to deny the existence of a Creator, that to regard the beginning of our earth as a process of development is to a.s.sert that development has been in operation from the beginning of all things. But when we recognise clearly that vastness and minuteness, prolonged and brief duration, are merely relative, we perceive that in considering our earth"s history we have to deal only with small parts of s.p.a.ce and brief periods of time, by comparison with all s.p.a.ce and all time. Our earth is very large compared with a tree or an animal, but very small compared with the solar system, a mere point compared with the system of stars to which the sun belongs, and absolutely as nothing compared with the universe of s.p.a.ce; and in like manner, while the periods of her growth and development occupy periods very long-lasting compared with those required for the growth and development of a tree or an animal, they are doubtless but brief compared with the eras of the development of our solar system, a mere instant compared with the eras of the development of star-systems, and absolutely evanescent compared with eternity. We have no more reason for rejecting the belief in a Creator because our earth or the solar system is found to have developed to its present condition from an embryonic primordial state, than we have had ever since men first found that animals and trees are developed from the germ. The region of development is larger, the period of development lasts longer, but neither the one nor the other is infinite; and being finite, both one and the other are simply nothing by comparison with infinity. It is a startling thought, doubtless, that periods of time compared with which the life of a man, the existence of a nation, nay, the duration of the human race itself, sink into insignificance, should themselves in turn be dwarfed into nothingness by comparison with periods of a still higher order. But the thought is not more startling than that other thought which we have been compelled to admit--the thought that the earth on which we live, and the solar system to which it belongs, though each so vast that all known material objects are as nothing by comparison, are in turn as nothing compared with the depths of s.p.a.ce separating us from even the nearest among the fixed stars. One thought, as I have said, we have been compelled to admit, the other has not as yet been absolutely forced upon us. Though men have long since given up the idea that the earth and heavens have endured but a few thousand years, it is still possible to believe that the birth of our solar system, whether by creative act or by the beginning of processes of development, belongs to the beginning of all time. But this view cannot be regarded as even probable. Although it has never been proved that any definite relation must subsist between time (occupied by events) and s.p.a.ce (occupied by matter), the mind naturally accepts the belief that such a relation exists. As we find the universe enlarging under the survey of science, our conceptions of the duration of the universe enlarge also. When the earth was supposed to be the most important object in creation, men might reasonably a.s.sign to time itself (regarded as the interval between the beginning of the earth and the consummation of all things when the earth should perish) a moderate duration; but it is equally reasonable that, as the insignificance of the earth"s domain in s.p.a.ce is recognised, men should recognise also the presumable insignificance of the earth"s existence in time.
In this respect, although we have nothing like the direct evidence afforded by the measurement of s.p.a.ce, we yet have evidence which can scarcely be called in question. We find in the structure of our earth the signs of its former condition. We see clearly that it was once intensely hot! and we know from experimental researches on the cooling of various earths that many millions of years must have been required by the earth in cooling down from its former igneous condition. We may doubt whether Bischoff"s researches can be relied upon in details, and so be unwilling to a.s.sign with him a period of 350 millions of years to a single stage of the process of cooling. But that the entire process lasted tens of millions and probably hundreds of millions of years cannot be doubted. Recognising such enormous periods as these in the development of one of the smallest fruits of the great solar tree of life, we cannot but admit at least the reasonableness of believing that the larger fruits (Jupiter, for instance, with 340 times as much matter, and Saturn with 100 times) must require periods still vaster, probably many times larger. Indeed, science shows not only that this view is reasonable, but that no other view is possible. For the mighty root of the tree of life, the great orb of the sun, containing 340 _thousand_ times as much matter as the earth, yet mightier periods would be needed.
The growth and development of these, the parts of the great system, must of necessity require much shorter time-intervals than the growth and development of the system regarded as a whole. The enormous period when the germs only of the sun and planets existed as yet, when the chaotic substance of the system had not yet blossomed into worlds, the mighty period which is to follow the death of the last surviving member of the system, when the whole scheme will remain as the dead trunk of a tree remains after the last leaf has fallen, after the last movement of sap within the trunk--these periods must be infinite compared with those which measure the duration of even the mightiest separate members of the system.
But all this has been left unnoticed by those who have argued in support of the Brewsterian doctrine of a plurality of worlds. They argue as if it had never been shown that every member of the solar system, as of all other such systems in s.p.a.ce, has to pa.s.s through an enormously long period of preparation before becoming fit to be the abode of life, and that after being fit for life (for a period very long to our conceptions, but by comparison with the other exceedingly short) it must for countless ages remain as an extinct world. Or else they reason as though it had been proved that the relatively short life-bearing periods in the existence of the several planets must of necessity synchronise, instead of all the probabilities lying overwhelmingly the other way.
While this has been (in my judgment) a defect in what may be called the Brewsterian theory of other worlds, a defect not altogether dissimilar has characterised the opposite or Whewellite theory. Very useful service was rendered to astronomy by Whewell"s treatise upon, or rather against, the plurality of worlds, calling attention as it did to the utter feebleness of the arguments on which men had been content to accept the belief that other planets and other systems are inhabited. But some among the most powerfully urged arguments against that belief tacitly relied on the a.s.sumption of a similarity of general condition among the members of the solar system. For instance, the small mean density of Jupiter and Saturn had, on the Brewsterian theory, been explained as probably due to vast hollow s.p.a.ces in those planets" interiors--an explanation which (if it could be admitted) would leave us free to believe that Jupiter and Saturn may be made of the same materials as our own earth. With this was pleasantly intermixed the conception that the inhabitant of these planets may have his "home in subterranean cities warmed by central fires, or in crystal caves cooled by ocean tides, or may float with the Nereids upon the deep, or mount upon wings as eagles, or rise upon the pinions of the dove, that he may flee away and be at rest," with much more in the same fanciful vein. We now know that there can be no cavities more than a few miles below the crust of a planet, simply because, under the enormous pressures which would exist, the most solid matter would be perfectly plastic. But while Whewell"s general objection to the theory that Jupiter or Saturn is in the same condition as our earth thus acquires new force, the particular explanation which he gave of the planet"s small density is open to precisely the same general objection. For he a.s.sumes that, because the planet"s mean density is little greater than that of water, the planet is probably a world of water and ice with a cindery nucleus, or in fact just such a world as would be formed if a sufficient quant.i.ty of water in the same condition as the water of our seas were placed at Jupiter"s greater distance from the sun, around a nucleus of earthy or cindery matter large enough to make the density of the entire planet thus formed equal to that of Jupiter, or about one-third greater than the density of water. In this argument there are in reality two a.s.sumptions, of precisely the same nature as those which Whewell set himself to combat.
It is first a.s.sumed that some material existing on a large scale in our earth, and nearly of the same density as Jupiter, must const.i.tute the chief bulk of that planet, and secondly that the temperature of Jupiter"s globe must be that which a globe of such material would have if placed where Jupiter is. The possibility that Jupiter may be in an entirely different stage of planetary life--or, in other words, that the youth, middle life, and old age of that planet may belong to quite different eras from the corresponding periods of our earth"s life--is entirely overlooked. Rather, indeed, it may be said that the extreme probability of this, on any hypothesis respecting the origin of the solar system, and its absolute certainty on the hypothesis of the development of that system, are entirely overlooked.
A fair ill.u.s.tration of the erroneous nature of the arguments which have been used, not only in advocating rival theories respecting the plurality of worlds, but also in dealing with subordinate points, may be presented as follows:
Imagine a wide extent of country covered with scattered trees of various size, and with plants and shrubs, flowers and herbs, down to the minutest known. Let us suppose a race of tiny creatures to subsist on one of the fruits of a tree of moderate size, their existence as a race depending entirely on the existence of the fruit on which they subsist, while the existence of the individuals of their race lasts but for a few minutes. Furthermore, let there be no regular fruit season either on their tree or in their region of vegetable life, but fruits forming, growing, and decaying all the time.
Let us next conceive these creatures to be possessed of a power of reasoning respecting themselves, their fruit world, the tree on which it hangs, and to some degree even respecting such other trees, plants, flowers, and so forth, as the limited range of their vision might be supposed to include. It would be a natural thought with them, when first they began to exercise this power of reasoning, that their fruit home was the most important object in existence, and themselves the chief and n.o.blest of living beings. It would also be very natural that they should suppose the formation of their world to correspond with the beginning of time, and the formation of their race to have followed the formation of their world by but a few seconds. They would conclude that a Supreme Being had fashioned their world and themselves by special creative acts, and that what they saw outside their fruit world had been also specially created, doubtless to subserve their wants.
Let us now imagine that gradually, by becoming more closely observant than they had been, by combining together to make more complete observations, and above all by preserving the records of observations made by successive generations, these creatures began to obtain clearer ideas respecting their world and the surrounding regions of s.p.a.ce. They would find evidence that the fruit on which they lived had not been formed precisely as they knew it, but had undergone processes of development. The distressing discovery would be made that this development could not possibly have taken place in a few seconds, but must have required many hours, nay, even several of those enormous periods called by us days.