30 DECEMBER 1882, Page 10


THE recent observations made on the planet Venus during her transit across the Sun, appear to confirm the impres- sion derived from the last transit, in 1874, that she has an atmosphere not less dense than our own, and aqueous vapour and cloud within that atmosphere. This conclusion would have grieved the late Professor Whewell, who, in his ingenious essay to disprove the plurality of inhabited worlds, took for granted that "we discern no traces of a gaseous or watery atmosphere sur- rounding her [Venus]," and built on this negative evidence one of his arguments to prove that, in the whole Universe, the Earth is not improbably the only habitable globe. Professor Whewell did his best to show that the earth held a very singular place in what might be a very unique solar system ; that it occupied what he called " the temperate zone " of its own sun's system, and that there is no particular reason to suppose that any other sun has planetary attendants at all. In order to make out the singular position of the earth in its own sun's system, Professor Whewell was compelled to make the most of the intensity of the light and heat in Mer- cury and Venus, and the most, again, of the comparative cold of Mars. In point of fact, however, it is probable that very slight modification of our human organisation,—even if any structural modification at all of that organisation were necessary,—would enable creatures of the same general structure and habits as man to live with ease in either of the

planets nearest to the earth, in either Mars, which should, caeteris paribus, be colder and darker, or in Venus, which should, caeteris paribus, be lighter and hotter than the earth. We know, to some extent, the configuration of the continents in Mars, and our astronomers have at times watched the area of the polar snows of that planet increasing with the approach of winter, and dwindling with the approach of summer, Of Venus we know much less, the intense brightness of her reflected light being a very unfavourable condition for minute observation. But the apparently clear evidence for an atmo- sphere of a good deal of density, and for the presence of cloud and aqueous vapour in that atmosphere, disposes completely of the late Professor Whewell's assumption that no creature resembling man, now has, or could. ever have, his abode there. There now seems no reason to doubt that in Venus the con- ditions of physical existence are such that either there now may be there, or may have been, or may be in future, a being whose physical existence might, like that of man and the animal natures nearest to man, exist under something closely approaching to those of terrestrial life. The length of the day in Venus is nearly the same, the weight of any given mass is nearly the same, the atmospheric conditions are probably not very different from our own ; the only material differences being probably the length of the year, which is not very much above the half of ours—or, say, about seven months, instead of twelve—and the amount of light and heat, which, unless mitigated by special atmospheric conditions, as they easily might be, would probably be twice as intense as terrestrial light and heat.

We insist on this analogy, however, only for the sake of those who, like the late Dr. Whewell, made the argument from analogy so all-important, though in relation to a question on which, as it appears to us, the argument from analogy has really a very slight bearing indeed. There is no reason in the world why spiritual beings, much more like to us in their thoughts than it is at all pro- bable that birds and tortoises are like to us in their thoughts, should not exist everywhere,—in. the pure ether, in the hottest flames of the sun, in the dimness of the darkest recesses of space, iu the heart of the volcano, or in the depth of the ocean. Ignore the reasoning from analogy,—and we can hardly have a less secure basis for reasoning, where observation is limited, as it is in this case, to one minute corner of an infinite universe,—and we shall find no more reason why we should confine the Creator's power to working within conditions closely resembling our own, than there is why we should assume that he will work at all in regions where we have no evidence of that work. Nothing will give us a better idea of the utter arbitrariness of the argument from analogy, when it is used by creatures of extremely feeble powers as their only means of determining the direction and limits of the divine activity, than to suppose a reasoning bookworm,—we mean the genuine thing, and not the human being so nicknamed,— arguing from analogy that because it has verified the existence of a large supply of the food which best suits it,—say in some great public library,—therefore it may safely infer the exist- ence of a large and increasing population of bookworms, for whose consumption that ample provender is intended. The book- worm, being supposed entirely ignorant of the true use of books, would leave out of sight the trivial fact that his own existence, and that of his race, is regarded by the actual makers and keepers of these books as inconsistent with the purposes which lead men to produce and preserve them, and so all his argument from analogy would be worthless ; while if he could but know that what he regards as mere food to be passed into his stomach and there -digested and assimi- lated, other beings regard as infinitely more useful to them, if it never passes into any stomach, but is stored with as little injury to its form as is consistent with its being con- tinually passed under the eyes of this different order of beings, he might found on it a solid argument for inferring the existence and activity of that very different order of beings who really produce books, and do whatever is in their power to protect books from the ravages of himself and his species. Well, just as the bookworm, arguing from his own petty point of view, would found the most misleading inferences on the existence of a great public library, and be likely to deduce from it a totally mistaken concep- tion as to the numbers and destiny of bookworms,—so, as it -seems to us, even human beings, arguing to the habitation, or non-habitation, of other worlds than ours from the very in- sufficient premises of the physical analogies suggested by our own state of being, are as likely to make inferences concern- ing the Creator's purpose at least as false as the bookworm himself would have made in the case supposed. How do we know that the very conditions which we look upon as favourable to the life of beings like ourselves in worlds beyond our own, may not rather minister to the life of far higher beings, whose chief care it may be to prevent any evolution in their world of creatures like men whom they might regard as destruc- tive of, or at least noxious to, their own highest purposes P How do we know that these other worlds may not be full of beings who regard the planets where human life is possible much as we regard nests of wasps or hornets P How do we know, again, that if higher orders of beings exist and flourish there, they do not use the very physical conditions which we, in our narrow and petty sphere, think of only as subsidiary to the develop- ment of a bodily life like ours, for totally different ends, as auxiliary to moral characteristics of which we have absolutely no guess, or to the prosecution of studies of which we do not even possess the germs P The simple truth is that the argument from analogy in such a case as this is an argument hardly worth anything, so far as the right to found deliberate expectations on it goes. If it may be assumed that we know enough of the drift of creative purpose on the earth to infer from it the existence of a similar creative purpose in Mars and Venus so far as similar conditions exist ; and if we may assume that all the variations which may affect those conditions are insufficient to vary materially the scope of that creative purpose, why, then, it may be safe to say that beings somewhat like ourselves either do exist, or have existed, or will exist, in Mars and Venus ; but then, the "ifs" here are so tremendous, and attach to our mere ignorance of any material difference so much of the importance which would attach to a very different state of things, namely, the knowledge that there is no material difference, that the whole validity of the argument is vitiated by them. The truth is, that in arguments of this kind the only sure way is to argue from known differences of an essential kind, to known differ- ences of a corresponding kind. We can safely say that if the moon has no atmosphere and no aqueous vapour worth men- tioning, the whole organisation of living bodies there—if living bodies there be—must be totally different from the organisation of human bodies. We may safely say that if there be no atmosphere in the moon, there can be no lungs in the lunar inhabitants, and no winged creatures, and no balloons, and no vegetable growth of the sort which requires the constituents of the atmosphere to live upon ; and that if there be no aqueous vapour, there can be no seas, and no lakes, and no streams, and no snows, and no glaciers. So, again, we may safely say that if there be twice as much light and heat in Venus as there is on the earth, then, supposing bodies like those of the mammalia to exist, there must either be a groat modification of the physical structure of those bodies in Venus, fitting them to endure and enjoy much more light and heat than we can endure and enjoy, or else there must be some peculiar physical arrangements protecting the animals in Venus from the ex- cessive glare and heat. But we are wholly unable to say that there need. be bodies resembling ours at all,—or that even if there be none such, there may not yet be minds resembling ours, —or that the same physical conditions which we should re- gard here as specially adapted to produce particular physical results, may not there be important chiefly or wholly for the purpose of a totally different class of results of which we on form no conjecture. The truth is that, in our opinion, a great deal too much is made of the argument from analogy, when the facts on which we reason are a mere infinitesimal fraction of the facts which would be wanted in order to draw any certain inference. Granted the Creator's infinitude, it seems to us more than possible that beings of a totally different order from ourselves permeate the whole universe, stellar and ethereal not less than planetary. But for the actual existence of such beings, we have no analogies on which to reason with my confidence at all.

For the existence of physical conditions not unlike those of our own earth in a few specific planets, we have good evidence. But whether that constitutes any solid argument for the existence of beings like ourselves in those few planets, considering the enormous extent of our ignorance as to the totally different purposes which these conditions may also sub- serve, and the vastness of the differences in the play of life which a very slight change of physical condition might imply, we are very doubtful indeed. That creatures more or less like ourselves in physical constitution may exist in Venus and Mars, and cannot exist in the Moon, is perfectly dear. But that creatures like ourselves in physical constitution, do exist in Venus and Mars, or ever have existed there, or ever will exist there, we have, to our thinking, no substantial reason to believe. None the less, beings like ourselves in intellectual and moral, though not in bodily constitution, may people not only the planets most resembling the earth, but the infinite spaces of the universe, even those which least resemble the earth in any physical condition whatever.