The Plurality of Worlds

4. There is, however, one caution suggested by this view. Since, besides, and mixed with the examples of Design which the creation offers, there are also results of General Laws, in which we cannot trace the purpose and object of the law; we may fall into error, if we fasten upon something which is a result of such mere general laws, and imagine that we can discern its object and purpose. Thus, for instance, we might possibly persuade ourselves that we had discovered the use and purpose of the teats of male animals; or of the trace of separation into parts which the leg-bone of a horse offers; or of the false toes of a pig: all which are, as we have seen, the rudiments of a plan more general than is developed in the particular case. And if, when we had made such a fancied discovery, it were found that the uses and purposes which we had imagined to belong to these parts or features, were not really served by them; at first, perhaps, we might be somewhat disturbed, as having lost one of the evidences of the design of the Creator, all which are, precious to a reverent mind. But it is not likely that any disturbance of a reverent mind on such grounds as this, would continue long, or go far. We should soon come to recollect, how light and precarious, perhaps how arbitrary and ill-supported by our real knowledge, were the grounds on which we had assigned such uses to such parts. We should turn back from them to the more solid and certain evidences, not shaken, nor likely to be shaken, by any change in prevalent zoological or anatomical doctrines, which those who love to contemplate such subjects habitually dwell upon; and, holding ourselves ready to entertain any speculations by which the bearing of those general Laws upon Natural Religion could be shown, in such a way as to convince our reason, we should rest in the confident and tranquil persuasion that no success or failure in such speculations could vitally affect our belief in a wise and benevolent Deity:—that though additional illustrations of his attributes might be interesting and welcome, no change of our scientific point of view could make his being or action doubtful.

5. This is, it would seem, the manner in which a reasonable and reverent man would regard the proof of a Supreme Creator and Governor, which is derived from Design, as seen in the organic creation; and the mode in which such proof would be affected by changes in the knowledge which we may acquire of the general laws by which the organic creation is constituted and governed. And hence, if it should be found to be established by the researches of the most comprehensive and exact philosophy, that there are, in any province of the universe, resemblances, gradations, general laws, indications of the mode in which one form approaches to another, and seems to pass into and generate another, which tend to obliterate distinctions which at first appeared broad and conspicuous; still the argument, from the design which appears in the parts of which we most clearly see the purpose, would not lose its force. If, for instance, it should be made apparent, by geological investigations of the extinct fossil creation, that the animal forms which have inhabited the earth, have gradually approached to that type in which the human form is included, passing from the rudest and most imperfect animal organizations, mollusks, or even organic monads, to vertebrate animals, to warm-blooded animals, to monkeys, and to men; still, the evidences of design in the anatomy of man are not less striking than they were, when no such gradation was thought of. And what is more to the purpose of our argument, the evidences of the peculiar nature and destination of man, as shown in other characters than his anatomy,—his moral and intellectual nature, his history and capacities,—stand where they stood before; nor is the vast chasm which separates man, as a being with such characters as these latter, from all other animals, at all filled up or bridged over.

6. The evidence of design in the inorganic world,—in the relation of earth, air, water, heat and light,—is, to most persons, less striking and impressive, than it is in the organic creation. But even among these mere physical elements of the world, when we consider them with reference to living things, we find many arrangements which, on a reflective view, excite our admiration, by the beneficial effect, and seemingly beneficent purpose. Our condition is furnished with the solid earth, on which we stand, and in which we find the materials of man's handiworks; stone and metal, clay and sand;—with the atmosphere which we breathe, and which is the vehicle of oral intercourse between man and man;—with revolutions of the sun, by which are brought round the successions of day and night, through all their varying lengths, and of summer and winter;—with the clouds above us, which pour upon the earth their fertilizing showers. All this furniture of the earth, so marvellously adapting it for the abode of living creatures, and especially of man, may well be regarded as a collection of provisions for his benefit:—as intended to do him the good, which they do. Nor would this impression be removed, or even weakened, if we were to discover that some of these arrangements, instead of being produced by a machinery confined to that single purpose, were only partial results of a more general plan. For instance; we learn that the varying lengths of days and nights through the year, and the varying declination of the sun, are produced, not, as was at first supposed, by the sun moving round the earth, in a complex diurnal and annual path, but by the earth revolving in an annual orbit round the sun; while at the same time she has a diurnal rotation about her own axis, which axis, by the laws of mechanics, remains always parallel to itself. When we learn that this is so, we see that the effect is produced by a mechanical arrangement far more simple than any which the imagination of man had devised; but in this case, the effect is plainly rather an increased admiration at the simplicity of the mechanism, than a wavering belief in the reality of the purpose. In like manner when, instead of supposing water to exist in a continuous reservoir in a firmament above the earth, and to fall in the earlier and in the latter rain, by some special agency for that purpose; men learnt to see that the water in the upper regions of the air must exist in clouds and in vapors only, and must fall in showers by the condensing influence of cold currents of air; they needed not to cease to admire the kindness of the Creator, in providing the rain to water the earth, and the wind to dry it; although the mechanism by which the effect was produced was of a larger kind than they had before imagined. And even if this mechanism extend through the solar system: if the arrangement by which the Earth's atmosphere is the special region in which there are winds hot and cold, clouds compact or dissolving,—be an arrangement which extends its influence to other planets, as well as to ours;—if this mixed atmosphere be placed, not only at the meeting point of clear aqueous vapor above, and warmer airs below, but also at the meeting point of a hot central region surrounding the Sun, and a cold exterior zone in which water and vapor can exist in immense collected masses, such as are Jupiter and Saturn;—still it would not appear, to a reasonable view, that this larger expansion of the machinery by which the effect is produced, makes the machinery less remarkable; or can at all tend to diminish the belief that it was intended to produce the effect which it does produce. Hot and cold, moist and dry, are constantly mixed together for the support of vegetable and animal life; and not the less so, if we believe that, though elements of this kind pervade the whole solar system, it is only at the Earth that they are combined so as to foster and nourish living things.

7. But it will perhaps be said, that to suppose the whole Solar System to be a machine merely operating for the benefit of the Earth and its population, is to give to the Earth and its population an importance in the scheme of creation which is quite extravagant and improbable:—it is to make the greater orbs, Jupiter and Saturn, minister to the less; instead of having their own purpose, and their own population, which their size naturally leads us to expect. To this we reply, that, in the first place, we have shown good reason for believing that the Earth is really the largest dense solid globe which exists in the solar system, and that the size of Jupiter and Saturn arises from their being composed mainly of water and vapor. And with regard to the difficulty of the greater ministering to the less;—if by greater, mere size and extent be understood, it appears to be the universal law of creation, that the greater, in that sense, should minister to the less, when the less includes living things. Even if the planets be all inhabited, the sun, which is greater far than all of them together, ministers light and heat to all of them. Even on this supposition, the vast spaces by which the planets are separated have no use, that we can discern, except to place them at suitable distances from the sun. Even on this supposition, their solid globes within, their atmospheres without are all merely subservient to the benefit of a thin and scattered population on the surface. The space occupied by men and animals on the earth's surface, even taking into account the highest buildings and the deepest seas, is only a few hundreds, or a thousand feet. The benefit of this minute shell, interrupted in many places for vast distances, everywhere loosely and sparsely filled, is ministered to by the solidity and attraction of a mass below it 20 millions of feet deep; by the influence of an atmosphere above it 200 thousand feet high at least, and it may be, much more. And this being so, if we increase the depth of the centre 20 thousand times; if we carry the extreme verge of air and vapor to thirty times the radius of the earth's orbit from us, how does the construction of the machine become more improbable, or the disproportion of its size to its purpose more incongruous? Is mere size,—extent of brute matter or blank space,—so majestic a thing? Is not infinite space large enough to admit of machines of any size without grudging? But if we thus move the centre of the Earth's peopled surface 20 thousand times further off, we reach the Sun. If we carry the limit of air and vapor to the distance of 30 times the radius of the Earth's orbit we arrive at Neptune. Are these new numbers monstrous, while the old ones were accepted without scruple? Is number such an alarming feature in the description of the Universe? Does not the description of every part and every aspect of it, present us with numbers so large, that wonder and repugnance, on that ground are long ago exhausted? Surely this is so: and if the evidence really tend to prove to us that all the solar system ministers to the earth's population; the mere size of the system, compared with the space occupied by the population, will not long stand in the way of the reception of such a doctrine.

8. But the objection will perhaps be urged in another form. It will be said that the other Planets have so many points of resemblance with the Earth, that we must suppose their nature and purpose the same. They, like the Earth, revolve in circles round the sun, rotate on their own axes, have, several of them, satellites, are opaque bodies, deriving light and probably heat from the sun. To an external spectator of the Solar System, they would not be distinguishable from the Earth. Such a spectator would never be tempted to guess that the Earth alone, of all these, neither the greatest nor the least, neither the one with the most satellites, nor the fewest, neither the innermost nor the outermost of the planets, is the only one inhabited; or at any rate the only one inhabited by an intelligent population. And to this we reply; that the largest of the other planets, if we judge rightly, are not like the Earth in one most essential respect, their density; and none of them, in having a surface consisting of land and water; except perhaps Mars: that if the supposed external spectator could see that this was so, he might see that the earth was different from the rest; and he might be able to see the vaporous nature of the outer planets, so that he would no more think of peopling them, than we do, of peopling the grand Alpine ridges and vallies which we see in the clouds of a summer-sky.

9. But even if the supposed spectator attended only to the obvious and superficial resemblances between one of the planets and another, he might still, if he were acquainted with the general economy of the Universe, have great hesitation in inferring that, if one of them were inhabited, the others also must be inhabited. For, as we have said, in the plan of creation, we have a profusion of examples, where similar visible structures do not answer a similar purpose; where, so far as we can see, the structure answers no purpose in many cases; but exists, as we may say, for the sake of similarity: the similarity being a general Law, the result, it would seem, of a creative energy, which is wider in its operation than the particular purpose. Such examples are, as we have said, the finger-bones which are packed into the hoofs of a horse, or the paps and nipples of a male animal. Now the spectator, recollecting such cases might say: I know that the earth is inhabited; no doubt Mars and Jupiter are a good deal like the Earth; but are they inhabited? They look like the terrestrial breast of Nature: but are they really nursing breasts? Do they, like that, give food to living offspring? Or are they mere images of such breasts? male teats, dry of all nutritive power? sports, or rather overworks of nature; marks of a wider law than the needs of Mother Earth require? many sketches of a design, of which only one was to be executed? many specimens of the preparatory process of making a Planet, of which only one was to be carried out into the making of a World? Such questions might naturally occur to a person acquainted with the course of creation in general; even before he remarked the features which tend to show that Jupiter and Saturn, that Venus and Mercury, have not been developed into peopled worlds, like our Earth.

10. Perhaps it may be said, that to hold this, is to make Nature work in vain; to waste her powers; to suppose her to produce the frame work, and not to build; to make the skeleton, and not to clothe it with living flesh; to delude us with appearances of analogy and promises of fertility, which are fallacious. What can we reply to this?

11. We reply, that to work in vain, in the sense of producing means of life which are not used, embryos which are never vivified, germs which are not developed; is so far from being contrary to the usual proceedings of nature, that it is an operation which is constantly going on, in every part of nature. Of the vegetable seeds which are produced, what an infinitely small proportion ever grow into plants! Of animal ova, how exceedingly few become animals, in proportion to those that do not; and that are wasted, if this be waste! It is an old calculation, which used to be repeated as a wonderful thing, that a single female fish contains in its body 200 millions of ova, and thus, might, of itself alone, replenish the seas, if all these were fostered into life. But in truth, this, though it may excite wonder, cannot excite wonder as anything uncommon. It is only one example of what occurs everywhere. Every tree, every plant, produces innumerable flowers, the flowers innumerable seeds, which drop to the earth, or are carried abroad by the winds, and perish, without having their powers unfolded. When we see a field of thistles shed its downy seeds upon the wind, so that they roll away like a cloud, what a vast host of possible thistles are there! Yet very probably none of them become actual thistles. Few are able to take hold of the ground at all; and those that do, die for lack of congenial nutriment, or are crushed by external causes before they are grown. The like is the case with every tribe of plants.68 The like with every tribe of animals. The possible fertility of some kinds of insects is as portentous as anything of this kind can be. If allowed to proceed unchecked, if the possible life were not perpetually extinguished, the multiplying energies perpetually frustrated, they would gain dominion over the largest animals, and occupy the earth. And the same is the case, in different degrees, in the larger animals. The female is stocked with innumerable ovules, capable of becoming living things: of which incomparably the greatest number end as they began, mere ovules;—marks of mere possibility, of vitality frustrated. The universe is so full of such rudiments of things, that they far outnumber the things which outgrow their rudiments. The marks of possibility are much more numerous than the tale of actuality. The vitality which is frustrated is far more copious than the vitality which is consummated. So far, then, as this analogy goes, if the earth alone, of all the planetary harvest, has been a fertile seed of creation;—if the terrestrial embryo have alone been evolved into life, while all the other masses have remained barren and dead:—we have, in this, nothing which we need regard as an unprecedented waste, an improbable prodigality, an unusual failure in the operations of nature: but on the contrary, such a single case of success among many of failure, is exactly the order of nature in the production of life. It is quite agreeable to analogy, that the Solar System, of which the flowers are not many, should have borne but one fertile flower. One in eight, or in twice eight, reared into such wondrous fertility as belongs to the Earth, is an abundant produce, compared with the result in the most fertile provinces of Nature. And even if any number of the Fixed Stars were also found to be barren flowers of the sky; objects, however beautiful, yet not sources of life or development, we need not think the powers of creation wasted or frustrated, thrown away or perverted. One such fertile result as the Earth, with all its hosts of plants and animals, and especially with Man, an intelligent being, to stand at the head of those hosts, is a worthy and sufficient produce, so far as we can judge of the Creator's ways by analogy, of all the Universal Scheme.

12. But when we follow this analogy, so far as to speak of the mere material mass of a planet as an embryo world;—a barren flower;—a seed which has never been developed into a plant;—we are in danger of allowing the analogy to mislead us. For a planet, as to its brute mass, has really nothing in common with a seed or an embryo. It has no organization, or tendency to organization; no principle of life, however obscure. So far as we can judge, no progress of time, or operation of mere natural influence, would clothe a brute mass with vegetables, or stock it with animals. No species of living thing would have its place upon the surface; by the mere order of unintelligent nature. So much is this so, according to all that our best knowledge teaches, that those geologists who must most have desired, for the sake of giving completeness and consistency to their systems, to make the production of vegetable and animal species from brute matter, a part of the order of nature, (inasmuch as they have explained everything else by the order of nature,) have not ventured to do so. They allow, generally at least, each separate species to require a special act of creative power, to bring it into being. They make the peopling of the earth, with its successive races of inhabitants, a series of events altogether different from the operation of physical laws in the sustentation of existing species. The creation of life is, they allow, something out of the range of the ordinary laws of nature. And therefore, when we speak of uninhabited planets, as cases in which vital tendencies have been defeated; in which their apparent destiny, as worlds of life, has been frustrated; we really do injustice to our argument. The planets had no vital tendencies: they could have had such given, only by an additional act, or a series of additional acts, of Creative power. As mere inert globes, they had no settled destiny to be seats of life: they could have such a destiny, only by the appointment of Him who creates living things, and puts them in the places which he chooses for them. If, when a planetary mass had come into being, (in virtue of the same general physical law, suppose, which produced the earth,) the Creator placed a host of living things upon the earth, and none upon the other planet; there was still no violation of analogy, no seeming change of purpose, no unfinished plan. In the solar system, we can see what seem to be good reasons why he did this; but if we could not see such reasons, still we should be yet further from being able to see reasons why he necessarily must place inhabitants upon the other planet.

13. It is sometimes said, that it is agreeable to the goodness of God, that all parts of the creation should swarm with life; that life is enjoyment; and that the benevolence of the Supreme Being is shown in the diffusion of such enjoyment into every quarter of the universe. To leave a planet without inhabitants, would, it is thought, be to throw away an opportunity of producing happiness. Now we shall not here dwell upon the consideration, that the enjoyment thus spoken of, is, in a great degree, the enjoyment which the mere life of the lower tribes of animals implies;—the enjoyment of madrepores and oysters, cuttle-fish and sharks, tortoises and serpents; but we reply more broadly, that it is not the rule followed by the Creator, to fill all places with living things. To say nothing of the vast intervals between planet and planet, which, it is presumed, no one supposes to be occupied by living things; how large a portion of the surface of the earth is uninhabited, or inhabited only in the scantiest manner. Vast desert tracts exist in Africa and in Asia, where the barren sand nourishes neither animal nor vegetable life. The highest regions of mountain-ranges, clothed with perpetual snow, and with far-reaching sheets of glacier ice, are untenanted, except by the chamois at their outskirts. There are many uninhabited islands; and were formerly many more. The ocean, covering nearly three-fourths of the globe, is no seat of habitation for land animals or for man; and though it has a large population of the fishy tribes, is probably peopled in smaller numbers than if it were land, as well as by inferior orders. We see, in the Earth then, which is the only seat of life of which we really know anything, nothing to support the belief that every field in the material universe is tenanted by living inhabitants.

14. That vegetables and animals, being once placed upon the earth, have multiplied or are multiplying, so as to occupy every part of the land and water which is suited for their habitation, we can see much reason to believe. Philosophical natural-historians have been generally led to the conviction that each species has had an original centre of dispersion, where it was first native, and that from this centre it has been diffused in all directions, as far as the circumstances of climate and soil were favorable to its production. But we can see also much reason to believe that this general diffusion of vegetable and animal life from centres, is a part of the order of nature which may often be made to give way to other and higher purposes;—to the diffusion, over the whole surface of the earth, of a race of intelligent, moral agents. This process may often interfere with the general law of diffusion: as for instance, when man exterminates noxious animals. And whatever may be the laws which tend to replenish the earth, on which such centres of the diffusion of life exist for animals and plants; according to all analogy, these laws can have no force on any other planet, till such origins and centres of life are established on their surfaces. And even if any of the species which have ever tenanted the earth were so established on any other planet, we have the strongest reason to believe that they could not survive to a second generation.

15. Perhaps it may be said that we unjustifiably limit the power and skill of the Supreme Creator, if we deny that he could frame creatures fitted to live on any of the other planets, as well as in the Earth:—that the wonderful variety, and unexpected resource, of the ways in which animals are adapted for all kinds of climates, habitations, and conditions, upon the earth, may give us confidence that, under conditions still more extended, in habitations still further removed, in climates going beyond the terrestrial extremes, still the same wisdom and skill may well be supposed to have devised possible modes of animal life.