Thoughts on Man: His Nature, Productions, and Discoveries | ||
ESSAY XXI.
OF ASTRONOMY.
SECTION I.
It can scarcely be imputed to me as profane, if I venture to put down a few sceptical doubts on the science of astronomy. All branches of knowledge are to be considered as fair subjects of enquiry: and he that has never doubted, may be said, in the highest and strictest sense of the word, never to have believed.
The first volume that furnished to me the groundwork of the following doubts, was the book commonly known by the name of Guthrie's Geographical Grammar, many parts and passages of which engaged my attention in my own study, in the house of a rural schoolmaster, in the year 1772. I cannot therefore proceed more fairly than by giving here an extract of certain passages in that book, which have relation to the present subject. I know not how far they have been altered in the edition of Guthrie which now lies before me, from the language of the book then in my possession; but I feel confident that in the main particulars they continue the same[1].
"In passing rapidly over the heavens with his new telescope, the universe increased under the eye of Herschel; 44,000 stars, seen in the space of a few degrees, seemed to indicate that there were seventy-five millions in the heavens. But what are all these, when compared with those that fill the whole expanse, the boundless field of æther?
"The immense distance of the fixed stars from our earth, and from each other, is of all considerations the most proper for raising our ideas of the works of God. Modern discoveries make it probable that each of these stars is a sun, having planets and comets revolving round it, as our sun has the earth and other planets revolving round him.—A ray of light, though its motion is so quick as to be commonly thought instantaneous, takes up more time in travelling from the stars to us, than we do in making a West-India voyage. A sound, which, next to light, is considered as the quickest body we are acquainted with, would not arrive to us from thence in 50,000 years. And a cannon-ball, flying at the rate of 480 miles an hour, would not reach us in 700,000 years.
"From what we know of our own system, it may be reasonably concluded, that all the rest are with equal wisdom contrived, situated, and provided with accommodations for rational inhabitants.
"What a sublime idea does this suggest to the human imagination, limited as are its powers, of the works of the Creator! Thousands and thousands
The thought that would immediately occur to a dispassionate man in listening to this statement, would be, What a vast deal am I here called on to believe!
Now the first rule of sound and sober judgment, in encountering any story, is that, in proportion to the magnitude and seemingly incredible nature of the propositions tendered to our belief, should be the strength and impregnable nature of the evidence by which those propositions are supported.
It is not here, as in matters of religion, that we are called upon by authority from on high to believe in mysteries, in things above our reason, or, as it may be, contrary to our reason. No man pretends to a revelation from heaven of the truths of astronomy. They have been brought to light by the faculties of the human mind, exercised upon such facts and circumstances as our industry has set before us.
To persons not initiated in the rudiments of astronomical science, they rest upon the great and high-sounding names of Galileo, Kepler, Halley
The modest enquirer therefore, without pretending to put himself on an equality with these illustrious men, may be forgiven, when he permits himself to suggest a few doubts, and presumes to examine the grounds upon which he is called upon to believe all that is contained in the above passages.
Now the foundations upon which astronomy, as here delivered, is built, are, first, the evidence of our senses, secondly, the calculations of the mathematician, and, in the third place, moral considerations. These have been denominated respectively, practical astronomy, scientific, and theoretical.
As to the first of these, it is impossible for us on this occasion not to recollect what has so often occurred as to have grown into an every-day observation, of the fallibility of our senses.
It may be doubted however whether this is a just statement. We are not deceived by our senses, but deceived in the inference we make from our sensations. Our sensations respecting what we call the external world, are chiefly those of length, breadth and solidity, hardness and softness, heat and cold, colour, smell, sound and taste. The inference which the generality of mankind make in relation to these
Modern philosophy has taught us, in certain cases, to controvert the position, that the causes of our sensations are like to the sensations themselves. Locke in particular has called the attention of the reasoning part of mankind to the consideration, that heat and cold, sweet and bitter, and odour offensive or otherwise, are perceptions, which imply a percipient being, and cannot exist in inanimate substances. We might with equal propriety ascribe pain to the whip that beats us, or pleasure to the slight alternation of contact in the person or thing that tickles us, as suppose that heat and cold, or taste, or smell are any thing but sensations.
The same philosophers who have called our attention to these remarks, have proceeded to shew that the causes of our sensations of sound and colour have no precise correspondence, do not tally with the sensations we receive. Sound is the result of a percussion of the air. Colour is produced by the reflection of the rays of light; so that
It follows that, if there were no percipient being to receive these sensations, there would be no heat or cold, no taste, no smell, no sound, and no colour.
Aware of this difference between our sensations in certain cases and the causes of these sensations, Locke has divided the qualities of substances in the material universe into primary and secondary, the sensations we receive of the primary representing the actual qualities of material substances, but the sensations we receive of what he calls the secondary having no proper resemblance to the causes that produce them.
Now, if we proceed in the spirit of severe analysis to examine the primary qualities of matter, we shall not perhaps find so marked a distinction between those and the secondary, as the statement of Locke would have led us to imagine.
The Optics of Newton were published fourteen years later than Locke's Essay concerning Human Understanding.
In endeavouring to account for the uninterrupted transmission of rays of light through transparent substances, however hard they may be found to be, Newton has these observations.
"Bodies are much more rare and porous, than is commonly believed. Water is nineteen times lighter, and by consequence nineteen times rarer, than gold; and gold is so rare, as very readily, and without the least opposition, to transmit the magnetic effluvia, and easily to admit quicksilver into its pores, and to let water pass through it. From all which we may conclude, that gold has more pores than solid parts, and by consequence that water has above forty times more pores than parts. And he that shall find out an hypothesis, by which water may be so rare, and yet not capable of compression by force, may doubtless, by the same hypothesis, make gold, and water, and all other bodies, as much rarer as he pleases, so that light may find a ready passage through transparent substances[2]."
Again:
In the Queries annexed to the Optics, Newton further suggests an opinion, that the rays of light are repelled by bodies without immediate contact. He observes that:
"Where attraction ceases, there a repulsive virtue ought to succeed. And that there is such a virtue, seems to follow from the reflexions and inflexions of the rays of light. For the rays are repelled by bodies, in both these cases, without the immediate contact of the reflecting or inflecting body. It seems also to follow from the emission of light; the ray, so soon as it is shaken off from a shining body by the vibrating motion of the parts of the body, and gets beyond the reach of attraction, being driven away with exceeding great velocity. For that force, which is sufficient to turn it back in reflexion, may be sufficient to emit it. It
Newton was of opinion that matter was made up, in the last resort, of exceedingly small solid particles, having no pores, or empty spaces within them. Priestley, in his Disquisitions relating to Matter and Spirit, carries the theory one step farther; and, as Newton surrounds his exceedingly small particles with spheres of attraction and repulsion, precluding in all cases their actual contact, Priestley is disposed to regard the centre of these spheres as mathematical points only. If there is no actual contact, then by the very terms no two particles of matter were ever so near to each other, but that they might be brought nearer, if a sufficient force could be applied for that purpose. You had only another sphere of repulsion to conquer; and, as there never is actual contact, the whole world is made up of one sphere of repulsion after another, without the possibility of ever arriving at an end.
"The principles of the Newtonian philosophy," says our author, "were no sooner known, than it
It is then with senses, from the impressions upon which we are impelled to draw such false conclusions, and that present us with images altogether unlike any thing that exists out of ourselves, that we come to observe the phenomena of what we call the universe. The first observation that it is here incumbent on us to make, and which we ought to keep ever at hand, to be applied as occasion may offer, is the well known aphorism of Socrates, that "we know only this, that we know nothing." We have no compass to guide us through the pathless waters of science; we have no revelation, at least on the subject of astronomy, and of the unnumbered inhabitable worlds that float in the ocean of ether; and we are bound therefore to sail, as the mariners of ancient times sailed, always within sight of land. One of the earliest maxims of ordinary
There are indeed many objects with which we are conversant, that are in so various ways similar to each other, that, after having carefully examined a few, we are satisfied upon slighter investigation to admit the dimensions and character of others. Thus, having measured with a quadrant the height of a tower, and found on the narrowest search and comparison that the report of my instrument was right, I yield credit to this process in another instance, without being at the trouble to verify its results in any more elaborate method.
The reason why we admit the inference flowing from our examination in the second instance, and
But the interval that divides the objects which occur upon and under the earth, and are accessible in all ways to our examination, on the one hand, and the lights which are suspended over our heads in the heavens on the other, is of the broadest and most memorable nature. Human beings, in the
It is however one of the effects of the improvement of our intellect, to enlarge our curiosity. The daringness of human enterprise is one of the prime glories of our nature. It is our boast that we undertake to "measure earth, weigh air, and state the tides." And, when success crowns the boldness of our aspirations after what vulgar and timorous prudence had pronounced impossible, it is then chiefly that we are seen to participate of an essence divine.
What has not man effected by the boldness of his conceptions and the adventurousness of his spirit? The achievements of human genius have appeared so incredible, till they were thoroughly examined, and slowly established their right to general acceptance, that the great heroes of intellect were universally regarded by their contemporaries as dealers in magic, and implements of the devil. The inventor of the art of printing, that glorious instrument for advancing the march of human improvement, and the discoverer of the more questionable
As was stated in the commencement of this Essay, we know our own sensations, and we know little more. Matter, whether in its primary or secondary qualities, is certainly not the sort of thing the vulgar imagine it to be. The illustrious Berkeley has taught many to doubt of its existence altogether; and later theorists have gone farther than this, and endeavoured to shew, that each man, himself while he speaks on the subject, and you and I while we hear, have no conclusive evidence to convince us, that we may not, each of us, for aught we know, be the only thing that exists, an entire universe to ourselves.
We will not however follow these ingenious persons to the startling extreme to which their speculations would lead us. But, without doing so, it will not misbecome us to be cautious, and to reflect what we do, before we take a leap into illimitable space.
The article Astronomy, in this book, appears to have been written by the well known James Ferguson.
Priestley, Disquisitions, Section II. I know not by whom this illustration was first employed. Among other authors, I find, in Fielding (Joseph Andrews, Book II, Chap. II), a sect of philosophers spoken of, who "can reduce all the matter of the world into a nutshell."
SECTION II.
"The sun," we are told, "is a solid body, ninety-five millions of miles distant from the earth we inhabit, one million times larger in cubic measurement, and to such a degree impregnated with heat, that a comet, approaching to it within a certain distance, was by that approximation raised to a heat two thousand times greater than that of red-hot iron."
It will be acknowledged, that there is in this statement much to believe; and we shall not be exposed to reasonable blame, if we refuse to subscribe to it, till we have received irresistible evidence of its truth.
It has already been observed, that, for the greater part of what we imagine we know on the surface or in the bowels of the earth, we have, or may have if we please, the evidence of more than one of our senses, combining to lead to the same conclusion. For the propositions of astronomy we have no sensible evidence, but that of sight, and an imperfect analogy, leading from those visible impressions which we can verify, to a reliance upon those which we cannot.
The first cardinal particular we meet with in the above statement concerning the sun, is the term, distance. Now, all that, strictly speaking, we can affirm respecting the sun and other heavenly bodies, is that we have the same series of impressions respecting
Before we affirm any thing, as of our own knowledge and competence, respecting heavenly bodies which are said to be millions of millions of miles removed from us, it would not perhaps be amiss that we should possess ourselves of a certain degree of incontestible information, as to the things which exist on the earth we inhabit. Among these, one of the subjects attended with a great degree of doubt and obscurity, is the height of the mountains with which the surface of the globe we inhabit is diversified. It is affirmed in the received books of elementary geography, that the Andes are the highest mountains in the world. Morse, in his American Gazetteer, third edition, printed at Boston in 1810[5], says, "The height of Chimborazzo, the most elevated point of the vast chain of the Andes, is 20,280 feet above the level of the sea, which is 7102 feet higher than any other mountain in the known world:" thus making the elevation of the mountains of Thibet, or whatever other rising ground the compiler had in his thought, precisely 13,178 feet above the level of the sea, and no more. This decision however has lately been contradicted. Mr. Hugh Murray, in an Account of Discoveries and Travels in Asia, published in 1820, has collated
The elevation of mountains, till lately, was in no way attempted to be ascertained but by the use of the quadrant) and their height was so generally exaggerated, that Riccioli, one of the most eminent astronomers of the seventeenth century, gives it as his opinion that mountains, like the Caucasus, may have a perpendicular elevation of fifty Italian miles[6]. Later observers have undertaken to correct the inaccuracy of these results through the application of the barometer, and thus, by informing themselves of the weight of the air at a certain elevation, proceeding to infer the height of the situation.
There are many circumstances, which are calculated to induce a circumspect enquirer to regard the affirmative positions of astronomy, as they are delivered by the most approved modern writers, with considerable diffidence.
They are founded, as has already been said, next to the evidence of our senses, upon the deductions of mathematical knowledge.
Mathematics are either pure or mixed.
Pure mathematics are concerned only with abstract propositions, and have nothing to do with
But this is not strictly the case. Mathematics are like those abstract and imaginary existences about which they are conversant. They may constitute in themselves, and in the apprehension of an infallible being, a science of certainty. But they come to us mixed and incorporated with our imperfections. Our faculties are limited; and we may be easily deceived, as to what it is that we see with transparent and unerring clearness, and what it is that comes to us through a crooked medium, refracting and distorting the rays of primitive truth. We often seem clear, when in reality the twilight of undistinguishing night has crept fast and far upon us. In a train of deductions, as in the steps of an arithmetical process, an error may have insinuated itself imperceptibly at a very early stage, rendering all the subsequent steps a wandering farther and farther from the unadulterated truth. Human mathematics, so to speak, like the length of life, are subject to the doctrine of chances. Mathematics
But, if in the case of pure mathematics, we are exposed to the chances of error and delusion, it is much worse with mixed mathematics. The moment we step out of the high region of abstraction, and apply ourselves to what we call external nature, we have forfeited that sacred character and immunity, which we seemed entitled to boast, so long as we remained inclosed in the sanctuary of unmingled truth. As has already been said, we know what passes in the theatre of the mind; but we cannot be said absolutely to know any thing more. In our speculations upon actual existences we are not only subject to the disadvantages which arise from the limited nature of our faculties, and the errors which may insensibly creep upon us in the process. We are further exposed to the operation of the unevennesses and irregularities that perpetually occur in external nature, the imperfection of our senses, and of the instruments we construct to assist our observations, and the discrepancy which we frequently detect between the actual nature of the things about us and our impressions respecting them.
This is obvious, whenever we undertake to apply the processes of arithmetic to the realities of life. Arithmetic, unsubjected to the impulses of passion and the accidents of created nature, holds on its course; but, in the phenomena of the actual world, "time and chance happeneth to them all."
Thus it is, for example, in the arithmetical and geometrical ratios, set up in political economy by the celebrated Mr. Malthus. His numbers will go on smoothly enough, 1, 2, 4, 8, 16, 32, as representing the principle of population among mankind, and 1, 2, 3, 4, 5, 6, the means of subsistence; but restiff and uncomplying nature refuses to conform herself to his dicta.
Dr. Price has calculated the produce of one penny, put out at the commencement of the Christian era to five per cent. compound interest, and finds that in the year 1791 it would have increased to a greater sum than would be contained in three hundred millions of earths, all solid gold. But what has this to do with the world in which we live? Did ever any one put out his penny to interest in this fashion for eighteen hundred years? And, if he did, where was the gold to be found, to satisfy his demand?
Morse, in his American Gazetteer, proceeding on the principles of Malthus, tells us that, if the city of New York goes on increasing for a century in a certain ratio, it will by that time contain 5,257,493 inhabitants. But does any one, for himself or his posterity, expect to see this realised?
Blackstone, in his Commentaries on the Laws of England, has observed that, as every man has two ancestors in the first ascending degree, and four in the second, so in the twentieth degree he has more than a million, and in the fortieth the square of
Berkeley, whom I have already referred to on another subject, and who is admitted to be one of our profoundest philosophers, has written a treatise[7] to prove, that the mathematicians, who object to the mysteries supposed to exist in revealed religion, "admit much greater mysteries, and even falshoods in science, of which he alleges the doctrine of fluxions as an eminent example[8]." He observes, that their conclusions are established by virtue of a twofold error, and that these errors, being in contrary directions, are supposed to compensate each other, the expounders of the doctrine thus arriving at what they call truth, without being able to shew how, or by what means they have arrived at it.
It is a memorable and a curious speculation to reflect, upon how slight grounds the doctrine of "thousands and thousands of suns, multiplied without end, and ranged all around us, at immense distances from each other, and attended by ten thousand times ten thousand worlds," mentioned
It gives us a mighty and sublime idea of the nature of man, to think with what composure and confidence a succession of persons of the greatest genius have launched themselves in illimitable space, with what invincible industry they have proceeded, wasting the midnight oil, racking their faculties, and almost wearing their organs to dust, in measuring the distance of Sirius and the other fixed stars, the velocity of light, and "the myriads of intelligent beings formed for endless progression in perfection and felicity," that people the numberless worlds of which they discourse. The illustrious names of Copernicus, Galileo, Gassendi, Kepler, Halley and Newton impress us with awe; and, if the astronomy they have opened before us is a romance, it is at least a romance more seriously and perseveringly handled than any other in the annals of literature.
A vulgar and a plain man would unavoidably ask
The whole doctrine of astronomy rests upon trigonometry, a branch of the science of mathematics which teaches us, having two sides and one angle, or two angles and one side, of a triangle given us, to construct the whole. To apply this principle therefore to the heavenly bodies, it is necessary for us to take two stations, the more remote from each other the better, from which our observations should be made. For the sake of illustration we will suppose them to be taken at the extremes of the earth's diameter, in other words, nearly eight thousand miles apart from each other, the thing itself having never been realised to that extent. From each of these stations we will imagine a line to be drawn, terminating in the sun. Now it seems easy, by means of a quadrant, to find the arch of a circle (in other words, the angle) included between these lines
It is however obvious to the most indifferent observer, that the more any triangle, or other mathematical diagram, falls within the limits which our senses can conveniently embrace, the more securely, when our business is practical, and our purpose to apply the result to external objects, can we rely on the accuracy of our results. In a case therefore like the present, where the base of our isosceles triangle is to the other two sides as eight units to twelve thousand, it is impossible not to perceive that it behoves us to be singularly diffident as to the conclusion at which we have arrived, or rather it behoves us to take for granted that we are not unlikely to fall into the most important error. We have satisfied ourselves that the sides of the triangle including the apex, do not form an angle, till they have arrived at the extent of ninety-five millions of miles. How are we sure that they do then? May not lines which have reached to so amazing a length without meeting, be in reality parallel lines? If an
It being obvious that this was a very unsatisfactory scheme for arriving at the knowledge desired, the celebrated Halley suggested another method, in the year 1716, by an observation to be taken at the time of the transit of Venus over the sun[9].
It was supposed that we were already pretty accurately acquainted with the distance of the moon from the earth, it being so much nearer to us, by observing its parallax, or the difference of its place in the heavens as seen from the surface of the earth, from that in which it would appear if seen from its centre[10]. But the parallax of the sun is so exceedingly small, as scarcely to afford the basis of a mathematical calculation[11]. The parallax of Venus is however almost four times as great as that of the sun; and there must therefore be a very sensible difference between the times in which Venus may be seen passing over the sun from different parts of the earth. It was on this account apprehended, that the parallax of the sun, by means of observations taken from different places at the time of the transit of Venus in 1761 and 1769, might be ascertained with a great degree of precision[12].
But the imperfectness of our instruments and
"The true quantity of the moon's parallax," says Bonnycastle, "cannot be accurately determined by the methods ordinarily resorted to, on account of the varying declination of the moon, and the inconstancy of the horizontal refractions, which are perpetually changing according to the state the atmosphere is in at the time. For the moon continues but for a short time in the equinoctial, and the refraction at a mean rate elevates her apparent place near the horizon, half as much as her parallax depresses it[13]."
"It is well known that the parallax of the sun can never exceed nine seconds, or the four-hundredth part of a degree[14]." "Observations," says Halley, "made upon the vibrations of a pendulum, to determine these exceedingly small angles, are not sufficiently accurate to be depended upon; for by this method of ascertaining the parallax, it will sometimes come out to be nothing, or even negative; that is, the distance will either be infinite, or greater than infinite, which is absurd. And, to confess the truth, it is hardly possible for a person to distinguish seconds with certainty by any instruments, however skilfully they may be made; and therefore it is not to be wondered at, that the excessive nicety of this matter should have eluded the
Such are the difficulties that beset the subject on every side. It is for the impartial and dispassionate observers who have mastered all the subtleties of the science, if such can be found, to determine whether the remedies that have been resorted to to obviate the above inaccuracies and their causes, have fulfilled their end, and are not exposed to similar errors. But it would be vain to expect the persons, who have "scorned delights, and lived laborious days" to possess themselves of the mysteries of astronomy, should be impartial and dispassionate, or be disposed to confess, even to their own minds, that their researches were useless, and their labours ended in nothing.
It is further worthy of our attention, that the instruments with which we measure the distance of the earth from the sun and the planets, are the very instruments which have been pronounced upon as incompetent in measuring the heights of mountains[16]. In the latter case therefore we have substituted a different mode for arriving at the truth, which is supposed to be attended with greater precision: but we have no substitute to which we can resort, to correct the mistakes into which we may fall respecting the heavenly bodies.
The result of the uncertainty which adheres to
The doctrine of fluxions is likewise called in by the astronomers in their attempts to ascertain the distance and magnitude of the different celestial bodies which compose the solar system; and in this way their conclusions become subject to all the difficulties which Berkeley has alleged against that doctrine.
Kepler has also supplied us with another mode
Thus far however we proceed as we may, respecting our propositions on the subject of the solar system. But, beyond this, all science, real or pretended, deserts us. We have no method for measuring angles, which can be applied to the fixed stars; and we know nothing of any revolutions they perform. All here therefore seems gratuitous: we reason from certain alleged analogies; and we can do no more.
Huygens endeavoured to ascertain something on the subject, by making the aperture of a telescope so small, that the sun should appear through it no larger than Sirius, which he found to be only in the proportion of 1 to 27,664 times his diameter, as seen by the naked eye. Hence, supposing Sirius to be a globe of the same magnitude as the sun, it
And yet, from this small postulate, the astronomers proceed to deduce the most astounding conclusions. They tell us, that the distance of the nearest fixed star from the earth is at least 7,600,000,000,000 miles, and of another they name, not less than 38 millions of millions of miles. A cannon-ball therefore, proceeding at the rate of about twenty miles in a minute would be 760,000 years in passing from us to the nearest fixed star, and 3,800,000 in passing to the second star of which we speak. Huygens accordingly concluded, that it was not impossible, that there might be stars at such inconceivable distances from us, that their light has not yet reached the earth since its creation[20].
The received system of the universe, founded upon these so called discoveries, is that each of the stars is a sun, having planets and comets revolving round it, as our sun has the earth and other planets revolving round him. It has been found also by the successive observations of astronomers, that a star now and then is totally lost, and that a new star makes its appearance which had never been remarked before: and this they explain into the
Certainly the astronomers are a very fortunate and privileged race of men, who talk to us in this oracular way of "the unseen things of God from the creation of the world," hanging up their conclusions upon invisible hooks, while the rest of mankind sit listening gravely to their responses, and unreservedly "acknowledging that their science is the
We have a sensation, which we call the sensation of distance. It comes to us from our sight and our other senses. It does not come immediately by the organ of sight. It has been proved, that the objects we see, previously to the comparison and correction of the reports of the organ of sight with those of the other senses, do not suggest to us the idea of distance, but that on the contrary whatever we see seems to touch the eye, even as the objects of the sense of feeling touch the skin.
But, in proportion as we compare the impressions made upon our organs of sight with the impressions made on the other senses, we come gradually to connect with the objects we see the idea of distance. I put out my hand, and find at first that an object of my sense of sight is not within the reach of my hand. I put out my hand farther, or by walking advance my body in the direction of the object, and I am enabled to reach it. From smaller experiments I proceed to greater. I walk towards a tree or a building, the figure of which presents itself to my eye, but which I find upon trial to have been far from me. I travel towards a place that I cannot see, but which I am told lies in a certain direction. I arrive at the place. It is thus, that by repeated experiments I acquire the idea of remote distances.
To confine ourselves however to the question of
The height of the Monument of London is something more than two hundred feet. Other elevations, the produce of human labour, are considerably higher. It is in the nature of the mind, that we conclude from the observation that we have verified, to the accuracy of another, bearing a striking analogy to the former, that we have not verified. But analogy has its limits. Is it of irresistible certainty, or is it in fact to be considered as approaching to certainty, because we have verified an observation extending to several hundred feet, that an observation extending to ninety-five millions of miles, or to the incredible distances of which Herschel so familiarly talks, is to be treated as a fact, or laid down as a principle in science? Is it reasonable to consider two propositions as analogous, when the thing affirmed in the one is in dimension many million times as great as the thing
All these questions an untrained and inquisitive mind will ask itself in the propositions of astronomy. We must believe or not, as we think proper or reasonable. We have no way of verifying the propositions by the trial of our senses. There they lie, to be received by us in the construction that first suggests itself to us, or not. They are something like an agreeable imagination or fiction: and a sober observer, in cold blood, will be disposed deliberately to weigh both sides of the question, and to judge whether the probability lies in favour of the actual affirmation of the millions of millions of
But I shall be told, that the results of our observations of the distances of the heavenly bodies are unvaried. We have measured the distances and other phenomena of the sun, the moon, Mercury, Venus, Mars, Jupiter, Saturn, and their satellites, and they all fall into a grand system, so as to convey to every unprejudiced mind the conviction that this system is the truth itself. If we look at them day after day, and year after year, we see them for ever the same, and performing the same divine harmony. Successive astronomers in different ages and countries have observed the celestial orbs, and swept the heavens, and for ever bring us back the same story of the number, the dimensions, the distances, and the arrangement of the heavenly bodies which form the subject of astronomical science.
This we have seen indeed not to be exactly the case. But, if it were, it would go a very little way towards proving the point it was brought to prove. It would shew that, the sensations and results being similar, the causes of those results must be similar to each other, but it would not shew that the causes were similar to the sensations produced. Thus, in the sensations which belong to taste, smell, sound, colour, and to those of heat and cold, there is all
It is further alleged, that we calculate eclipses, and register the various phenomena of the heavenly bodies. Thales predicted an eclipse of the sun, which took place nearly six hundred years before the Christian era. The Babylonians, the Persians, the Hindoos, and the Chinese early turned their attention to astronomy. Many of their observations were accurately recorded; and their tables extend to a period of three thousand years before the birth of Christ. Does not all this strongly argue the solidity of the science to which they belong? Who, after this, will have the presumption to question, that the men who profess astronomy proceed on real grounds, and have a profound knowledge of these things, which at first sight might appear to be set at a distance so far removed from our ken?
The answer to this is easy. I believe in all the astronomy that was believed by Thales. I do not question the statements relative to the heavenly bodies that were delivered by the wise men of the
Among the earliest astronomers of Greece were Thales, Anaximander, Anaximenes and Anaxagoras. Thales, we are told, held that the earth is a sphere or globe, Anaximenes that it is like a round, flat table; Anaximander that the sun is like a chariot-wheel, and is twenty-eight times larger than the earth. Anaxagoras was put in prison for affirming that the sun was by many degrees larger than the whole Peloponnesus[25]. Kep]er is of opinion that all the stars are at an equal distance from us, and are fixed in the same surface or sphere.
In reality the observations and the facts of astronomy do not depend either upon the magnitudes or the distances of the heavenly bodies. They proceed in the first place upon what may lie seen with the naked eye. They require an accurate and persevering attention. They may be assisted by telescopes. But they relate only to the sun and the planets. We are bound to ascertain, as nearly as possible, the orbits described by the different bodies in the solar system: but this has still nothing to do, strictly speaking, with their magnitudes or distances. It is required that we should know them in their relations to each other; but it is no preliminary
The unlimited ambition of the nature of man has discovered itself in nothing more than this, the amazing superstructure which the votaries of contemplation within the last two hundred years have built upon the simple astronomy of the ancients. Having begun to compute the distances of miles by millions, it appears clearly that nothing can arrest the more than eagle-flight of the human mind. The distance of the nearest fixed star from the earth, we are informed, is at least 7,000,000,000,000 miles, and of another which the astronomers name, not less than 38 millions of millions of miles. The particles of light are said to travel 193,940 miles in every second, which is above a million times swifter than the progress of a cannon-ball[26]. And Herschel has concluded, that the light issuing from the faintest nebulæ he has discovered, must have been at this rate two millions of years in reaching the Earth[27].
Ferguson, § 216. "Light moves," says Brewster, Optics, p. 2, "from one pole of the earth to the other in the 24th part of a second: a velocity which surpasses all comprehension.
SECTION III.
The next process of the modern astronomer is to affirm the innumerable orbs around us, discovered with the naked eye, or with which we are
Now it appears to me, that, in these assertions, the modern astronomers are taking upon themselves somewhat too boldly, to expound the counsels of that mysterious power, to which the universe is indebted for its arrangement and order.
We know nothing of God but from his works. Certain speculative men have adventured to reason upon the source of all the system and the wonders that we behold, à priori, and, having found that the creator is all powerful, all wise, and of infinite goodness, according to their ideas of power, wisdom and goodness, have from thence proceeded to draw their inferences, and to shew us in what manner the works of his hands are arranged and conducted by him. This no doubt they have done with the purest intentions in the world; but it is not certain, that their discretion has equalled the boldness of their undertaking.
The world that we inhabit, this little globe of earth, is to us an infinite mystery. Human imagination is unable to conceive any thing more consummate
But there are other parts of the system in which we live, which do not seem to correspond with those already enumerated. Before we proceed to
Intestine stone and ulcer, colic pangs,
Demoniac frenzy, moping melancholy,
And moon-struck madness, pining atrophy,
Marasmus, and wide-wasting pestilence,
Dropsies, and asthmas, and joint-racking rheums.
The very idea of our killing, and subsisting upon the flesh of animals, surely somewhat jars with our conceptions of infinite benevolence.
But, when we look at the political history of man, the case is infinitely worse. This too often seems one tissue of misery and vice. War, conquest, oppression, tyranny, slavery, insurrections, massacres, cruel punishments, degrading corporal infliction, and the extinction of life under the forms of law, are to be found in almost every page. It is as if an evil demon were let loose upon us, and whole nations, from one decad of years to another, were struck with the most pernicious madness. Certain
Let us descend from the great stage of the nations, and look into the obscurities of private misery. Which of us is happy? What bitter springs of misery overflow the human heart, and are borne by us in silence! What cruel disappointments beset us! To what struggles are we doomed, while we struggle often in vain! The human heart seems framed, as if to be the capacious receptacle of all imaginable sorrows. The human frame seems constructed, as if all its fibres were prepared to sustain varieties of torment. "In the sweat of thy brow shalt thou eat bread, till thou return to the earth." But how often does that sweat prove ineffective! There are men of whom sorrow seems to be the destiny, from which they can never escape. There are hearts, into which by their constitution it appears as if serenity and content could never enter, but which are given up to all the furious passions, or are for ever the prey of repining and depression.
Whom pleasure, power and affluence surround,
How many pine in want! How many shrink
Into the sordid hut, how many drink
The cup of grief, and eat the bitter bread
Of misery!
And, which aggravates the evil, almost all the worst vices, the most unprincipled acts, and the darkest passions of the human mind, are bred out of poverty and distress. Satan, in the Book of Job, says to the Almighty, "Thou hast blessed the work of thy servant, and his substance is increased in the land. But put forth thy hand now, and take away all that he hath; and he will curse thee to thy face." The prayer of Agar runs, "Feed me with food convenient for me; lest I be poor, and steal, and take the name of my God in vain."
It is with a deep knowledge of the scenes of life, that the prophet pronounces, "My thoughts are not your thoughts; neither are your ways my ways, saith the Lord."
All reflecting persons, who have surveyed the state of the world in which we live, have been struck with the contrarieties of sublunary things; and many hypotheses have been invented to solve the enigma. Some have maintained the doctrine of two principles, Oromasdes and Arimanius, the genius of good and of evil, who are perpetually contending with each other which shall have the greatest sway in the fortunes of the world, and each alternately acquiring the upper hand. Others have
The astronomer however proceeds from what we see of the globe of earth, to fashion other worlds of which we have no direct knowledge. Finding that there is no part of the soil of the earth into which our wanderings can penetrate, that is not turned to the account of rational and happy beings, creatures capable of knowing and adoring their creator, that nature does nothing in vain, and that the world is full of the evidences of his unmingled beneficence, according to our narrow and imperfect ideas of beneficence,
All this is well, so long as we view it as a bold and ingenious conjecture. On any other subject it would be so regarded; and we should consider it as reserved for the amusement and gratification of a fanciful visionary in the hour, when he gives up the reins to his imagination. But, backed as it is by a complexity of geometrical right lines and curves, and handed forth to us in large quartos, stuffed with calculations, it experiences a very different fortune. We are told that, "by the knowledge we derive from astronomy, our faculties are enlarged, our minds exalted, and our understandings clearly convinced, and affected with the conviction, of the existence, wisdom, power, goodness, immutability
It is singular, how deeply I was impressed with this representation, while I was a schoolboy, and was so led to propose a difficulty to the wife of the master. I said, "I find that we have millions of worlds round us peopled with rational creatures. I know not that we have any decisive reason for supposing these creatures more exalted, than the wonderful species of which we are individuals. We are imperfect; they are imperfect. We fell; it is reasonable to suppose that they have fallen also. It became necessary for the second person in the trinity to take upon him our nature, and by suffering for our sins to appease the wrath of his father. I am unwilling to believe that he has less commiseration for the inhabitants of other planets. But in that case it may be supposed that since the creation he has been making a circuit of the planets, and dying on the cross for the sins of rational creatures in uninterrupted succession." The lady was wiser than I, admonished me of the danger of being over-inquisitive, and said we should act more discreetly in leaving those questions to the judgment of the Almighty.
But thus far we have reasoned only on one side of the question. Our pious sentiments have led us to magnify the Lord in all his works, and, however
and, by means of our telescopes and our calculations, penetrate into mysteries not originally intended for us. According to the received Mosaic chronology we are now in the five thousand eight hundred and thirty-fifth year from the creation: the Samaritan version adds to this date. It is therefore scarcely in the spirit of a Christian, that Herschel talks to us of a light, which must have been two millions of years in reaching the earth. Moses describes the operations of the Almighty, in one of the six days devoted to the work of creation, as being to place "lights in the firmament of heaven, to divide the day from the night, to be for signs and for seasons, and for days and years, and to give light upon the earth; two great lights, the greater to rule the day, and the lesser the night; and the stars also." And Christ, prophesying what is to happen in the latter days, says, "The sun shall be darkened, and the moon shall not give her light, and the stars shall
SECTION IV.
It is also no more than just, that we should bear in mind the apparent fitness or otherwise, of these bodies, so far as we are acquainted with them, for the dwelling-place of rational creatures. Not to mention the probable extreme coldness of Jupiter and Saturn, the heat of the sunbeams in the planet Mercury is understood to be such as that water would unavoidably boil and be carried away[30], and we can scarcely imagine any living substance that would not be dissolved and dispersed in such an atmosphere. The moon, of which, as being so much nearer to us, we may naturally be supposed to know most, we are told by the astronomers has no water and no atmosphere, or, if any, such an atmosphere as would not sustain clouds and ascending vapour. To our eye, as seen through the telescope, it appears like a metallic substance, which has been burned by fire, and so reduced into the ruined and ragged condition in which we seem to behold it. The sun appears to be still less an appropriate habitation for rational, or for living creatures, than any of the planets. The comets, which describe an
The modern astronomers go on to account to us for the total disappearance of a star in certain cases, which, they say, may be in reality the destruction of a system, such as that of our sun and its attendant planets, while the appearance of a new star may, in like manner, be the occasional creation of a new system of planets. "We ought perhaps," says Herschel, "to look upon certain clusters of stars, and the destruction of a star now and then in some thousands of ages, as the very means by which the whole is preserved and renewed. These clusters
All this must appear to a sober mind, unbitten by the rage which grows out of the heat of these new discoverers, to be nothing less than astronomy run mad. This occasional creation of new systems and worlds, is in little accordance with the Christian scriptures, or, I believe, with any sober speculation upon the attributes of the creator. The astronomer seizes upon some hint so fine as scarcely by any ingenuity to be arrested, immediately launches forth into infinite space, and in an instant returns, and presents us with millions of worlds, each of them peopled with ten thousand times ten thousand inhabitants.
We spoke a while since of the apparent unfitness of many of the heavenly bodies for the reception of living inhabitants. But for all this these discoverers have a remedy. They remind us how unlike these inhabitants may be to ourselves, having other organs than ours, and being able to live in a very different temperature. "The great heat in the planet Mercury is no argument against its being inhabited; since the Almighty could as easily suit the bodies and constitutions of its inhabitants to the heat of their dwelling, as he has done ours to the temperature of our earth. And it is very probable that the people there have such an opinion of us, as we have
These are the remarks of Ferguson[33]. One of our latest astronomers expresses himself to the same purpose.
"We have no argument against the planets being inhabited by rational beings, and consequently by witnesses of the creator's power, magnificence and benevolence, unless it be said that some are much nearer the sun than the earth is, and therefore must be uninhabitable from heat, and those more distant from cold. Whatever objection this may be against their being inhabited by rational beings, of an organisation similar to those on the earth, it can have little force, when urged with respect to rational beings in general.
"But we may examine without indulging too much in conjecture, whether it be not possible that the planets may be possessed by rational beings, and contain animals and vegetables, even little different from those with which we are familiar.
"Is the sun the principal cause of the temperature of the earth? We have reason to suppose that it is not. The mean temperature of the earth, at a small depth from the surface, seems constant in summer and in winter, and is probably coeval with its first formation.
"At the planet Mercury, the direct heat of the
"At the Georgium Sidus, the direct influence of the sun is 360 times less than at the earth, and the sun is there seen at an angle not much greater than that under which we behold Venus, when nearest. Yet may not the mean temperature of the Georgium Sidus be nearly the same as that of the earth? May not its atmosphere more easily transmit the influence of the sun, and may not the matter of heat be more copiously combined, and more readily extricated, than with us? Whence changes of season similar to our own may take place. Even in the comets we may suppose no great change of temperature takes place, as we know of no cause which will deprive them of their mean temperature, and particularly if we suppose, that on their approach towards the sun, there is a provision for their atmosphere becoming denser. The tails they exhibit, when in the neighbourhood of the sun, seem in some measure to countenance this idea.
"We can hardly suppose the sun, a body three hundred times larger than all the planets together, was created only to preserve the periodic motions, and give light and heat to the planets. Many astronomers have thought that its atmosphere only is luminous, and its body opake, and probably of the same constitution as the planets. Allowing therefore that its luminous atmosphere only extricates heat, we see no reason why the sun itself should not be inhabited[34]."
There is certainly no end to the suppositions that may be made by an ingenious astronomer. May we not suppose that we might do nearly as well altogether without the sun, which it appears is at present of little use to us as to warmth and heat? As to light, the great creator might, for aught we know, find a substitute; feelers, for example, endued with a certain acuteness of sense: or, at all events, the least imaginable degree of light might answer every purpose to organs adapted to this kind of twilight. In that way the inhabitants of the Georgium Sidus are already sufficiently provided for; they appear to have as little benefit of the light as of the heat of the sun. How the satellites of the distant planets are supplied with light is a mystery, since their principals have scarcely any. Unless indeed, like the sun, they have a luminous atmosphere, competent to enlighten a whole system, themselves being opake. But in truth light in a
Now the only reason we have to believe in these extraordinary propositions, is the knowledge we possess of the divine attributes. From the force of this consideration it is argued that God will not leave any sensible area of matter unoccupied, and therefore that it is impossible that such vast orbs as we believe surround us even to the extent of infinite space, should not be "richly stored with rational beings, the capable witnesses of his power, magnificence and benevolence." All difficulties
It is with some degree of satisfaction that I perceive lord Brougham, the reputed author of the Preliminary Discourse to the Library of Useful Knowledge, at the same time that he states the dimensions and distances of the heavenly bodies in the usual way, says not a word of their inhabitants.
It is somewhat remarkable that, since the commencement of the present century, four new planets have been added to those formerly contained in the enumeration of the solar system. They lie between the planets Mars and Jupiter, and have been named Vesta, Juno, Ceres and Pallas. Brinkley speaks of them in this manner. "The very small magnitudes of the new planets Ceres and Pallas, and their nearly equal distances from the sun, induced Dr. Olbers, who discovered Pallas in 1802, nearly in the same place where he had observed Ceres a few months before, to conjecture that they were fragments of a larger planet, which had by some unknown cause been broken to pieces. It follows from the law of gravity, by which the planets are retained in their orbits, that each fragment would again, after every revolution about the
These additions certainly afford us a new epoch in the annals of the solar system, and of astronomy itself. It is somewhat remarkable, that Herschel, who in the course of his observations traced certain nebulæ, the light from which must have been two millions of years in reaching the earth, should never have remarked these planets, which, so to speak, lay at his feet. It reminds one of Esop's astrologer, who, to the amusement of his ignorant countrymen, while he was wholly occupied in surveying the heavens, suddenly found himself plunged in a pit. These new planets also we are told are fragments of a larger planet: how came this larger planet never to have been discovered?
Till Herschel's time we were content with six planets and the sun, making up the cabalistical
One of the most important lessons that can be impressed on the human mind, is that of self-knowledge
But man is not omnipotent. If he aspires to be worthy of honour, it is necessary that he should compute his powers, and what it is they are competent to achieve. The globe of earth, with "all that is therein," is our estate and our empire. Let us be content with that which we have. It were a pitiful thing to see so noble a creature struggling in a field, where it is impossible for him to distinguish himself, or to effect any thing real. There is no situation in which any one can appear more
Even astronomy is to a certain degree our own. We can measure the course of the sun, and the orbits of the planets. We can calculate eclipses. We can number the stars, assign to them their places, and form them into what we call constellations. But, when we pretend to measure millions of miles in the heavens, and to make ourselves acquainted with the inhabitants of ten thousand times ten thousand worlds and the accommodations which the creator has provided for their comfort and felicity, we probably engage in something more fruitless and idle, than the pigmy who should undertake to bend the bow of Ulysses, or strut and perform the office of a warrior clad in the armour of Achilles.
How beautiful is the "firmament; this majestical roof fretted with golden fire!" Let us beware how we mar the magnificent scene with our interpolations and commentaries! Simplicity is of the essence of the truly great. Let us look at the operations of that mighty power from which we ourselves derive our existence, with humility and reverential awe! It may well become us. Let us not "presume into the heaven of heavens," unbidden, unauthorised guests! Let us adopt the counsel of the apostle, and allow no man to "spoil us through vain philosophy." The business of human life is
Thoughts on Man: His Nature, Productions, and Discoveries | ||