Popular Science Monthly/Volume 28/December 1885/The Uniformity of Nature
|←Relations of Science to the Public Weal II||Popular Science Monthly Volume 28 December 1885 (1885)
The Uniformity of Nature
By Harvey Goodwin
|Sketch of Professor Alpheus Hyatt→|
By THE BISHOP OF CARLISLE.
THE chief interest felt by readers of the reminiscence of a meeting of the Metaphysical Society, contained in the August number of this review, will probably be found in the striking and really remarkable record of the discussion of a difficult subject by such men as we there find, and under such conditions as are there described. Whatever the subject of discussion, such a symposium so felicitously saved from oblivion could not fail to secure attention and much gratitude to the able chiel who took notes and printed it. But in truth the subject discussed is as interesting as the company who discussed it; and to the writer of the present paper has so proved itself, not only on general grounds, but also because the view which seems to him to be chiefly worthy of consideration, as being the most true and the most luminous, does not appear to have presented itself to the mind of any one of the speakers, or at all events not to have been expressed clearly.
The discussion, as reported, labors under the great defect that there was no preliminary attempt to define the meaning of the phrase which formed the subject of the argument. Yet the "unformity of Nature" is an expression which does not carry upon its front one clear meaning, and one clear meaning only, and therefore needs definition if the truth of any proposition supposed to be implied by it is either to THE UXIFORMITY OF NATURE. 249
be affirmed or to be denied. In some senses Nature is obviously not uniform. Take the case of the weather : what can have less of the character of uniformity? Take the seasons: and observe the appar- ently absolute absence of all rule as to the sequence of fruitful and unfruitful years. Take almost any instance of natural phenomena that you please : and the variety, the eccentricity, the lawlessness, will probably be quite as striking as any characteristic which can be described by the word uniformity. Anyhow, in commencing a dis- cussion, we ought to know precisely what the phrase to be discussed means, or at least what it is held to mean by the disputants engaged in the argument.
I observe that one of the interlocutors of the Metaphysical Soci- ety, Mr. Walter Bagehot, affirms that experience can not prove the uniformity of Nature, because it is impossible to say what the uni- formity of Nature means. If this be so, and I am not just now con- tradicting the assertion, all serious discussion must be at an end. It is very well to say that, although experience can never prove the ab- solute uniformity of Nature, it ought to " train us to bring our expec- tations into something like consistency with the uniformity of Na- ture." But why should we expect Nature to be uniform, unless we can give some good reason for believing in this uniformity ? And why should we trouble ourselves with a principle of uniformity, the mean- ing of which, by hypothesis, we are unable to assign ?
On the other hand, Mr. Ruskin could scarcely hope to carry many of the company with him when he avowed his disbelief in uniformity altogether, and affirmed that if told that the sun had stood still he would reply : " A miracle that the sun stands still ? Not at all — I al- ways expected it would," This view of the matter would seem to imply that there is no principle in Nature which can in any way be described as law or uniformity — a conclusion which is opposed to all our knowledge.
In default of a clear definition of the thesis proposed to the Meta- physical Society, the prevailing thought in the minds of the dispu- tants seems to me to have been, how far the belief in abnormal phe- nomena, commonly spoken of as miraculous, is consistent with such a belief concerning the laws of Nature as scientific men find themselves compelled to hold. The discussion had clearly an underlying theologi- cal character : to more than half the disputants (so at least it seems to me) the theological consequences of an alleged uniformity of Na- ture were the uppermost thought, and the feature of most pressing interest in the argument. It would ])e well, perhaps, if this theologi- cal bearing of the question could be avoided in discussion, "NVe should be more likely to arrive at a conclusion as to what the uniform- ity of Nature means, and to what extent the prineiple is true, if we could regard it entirely as a natural question, and one to be answered upon the ordinary grounds of observation and induction : and I ob-
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serve that Professor Huxley seems to recognize this view, or rather he regards the principle as one the truth of which is not proved, but which is valuable as a working hypothesis, and all the more valuable because it has never yet failed him. The separation of the principle from theological considerations is, however, practically impossible ; we must make up our minds to many a fight upon the frontiers of the natural and the supernatural. Not a few persons believe that the pos- sibility of religious faith, at this epoch of history, depends much upon the conclusions to which they come concerning the laws and operations of Nature ; and I will not venture to deny that they who so believe have some reason to give for their belief.
It is in accordance with the statement just now advanced with regard to the close practical connection between the principle of the uniformity of Nature and theology that we find the said principle brought at once to the front in the Bishop of London's recent " Bamp- ton Lectures," entitled " The Relations between Religion and Science." With the general argument and results of these undoubtedly able lectures I shall not here be concerned, but it will be much to my pur- pose to make a few observations upon what is said in the first of the series concerning the uniformity of Nature.
The earliest occasion upon which the phrase appears is to be found in the following sentence: "It will be admitted that the Supreme Postulate, without which scientific knowledge is impossible, is the Uniformity of Nature." *
Now, a postulate is a proposition which is granted as the basis of an argument, because its truth is conceived to be self-evident ; or at all events it is the simplest proposition to which a chain of reasoning can be reduced, and, if it be not granted, all further argument is im- possible. Thus, Euclid's first postulate is, that from one point a straight line can be drawn to any other point. But surely it can scarce- ly be said of the uniformity of Nature that it has anything of this simple and self-evidencing character. The question, moreover, is not whether scientific knowledge be possible or impossible without it ; if impossible, so much the worse for scientific knowledge. The ques- tion still recurs. Is the principle true ? Moreover, can it be averred that scientific knowledge is impossible without this postulate ? If so, why is it that the principle is not asserted in Newton's " Principia," or Laplace's "Mecanique Celeste," or the various treatises on light, heat, electricity, botany, and what not? Certainly it seems to me ex- tremely doubtful whether the " Supreme Postulate " either is admit- ted, or ought to be admitted, as the basis of scientific knowledge.
I suspect, however, that the bishop does not intend the word Pos- tulate to be taken in its strict scientific sense ; for he illustrates his position by reference to the discovery of the planet Neptune, which resulted from the assumption that the law of gravitation holds uni-
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versally, and tliat therefore the unexplaineil errors of Uranus were due to the action of an exterior planet. But this assumption was as different as possible from a postulate : it was only apj)lying in a new way a law which had already been veritied in so many and such diverse cases that there was scarcely the shadow of a doubt in the mind of any astronomer that it was, as its ordinary name professes it to be, untV'Ksal throughout the material cosmos.
I am confirmed in this belief by finding the subsequent statement that " the uniformity of Nature is a working hypothesis, and it never can be more " ; * which agrees very much with the view propounded by Professor Huxley at the meeting of the Metaphysical Society. But I am not quite sure that this is consistent with a pievious passage in the lecture, which runs thus :
This, then, is the answer to the question. "Why do we believe in the uniform- ity of Xature ? We believe in it because we find it so. Millions and millions of observations concur in exhibiting this uniformity. And, the longer our observa- tion of Xature goes on, the greater do we find the extent of it. Things which once seepied irregular are now known to be regular. Things that seemed inex- plicable on tills hypothesis are now explained. Every day seems to add not merely to the instances, but to the wide-ranging classes of phenomena that come under the rule."!"
The truth of which I am not concerned to dispute ; but the para- graph gives a very different complexion to the principle of the uni- formity of Nature from that which belongs to it, when regarded as a postulate upon which all scientific knowledge depends.
The truth which I think is postulated in the case of Nature is that which is involved in the idea of cause and effect. The Bishop of Lon- don refers to Hume's famous discussion of this question, and his con- clu'^ion that there is nothing more in cause and effect than the notion of invariable sequence. This conclusion has often been controverted, and the Bishop of London refers to the arguments of Kant and of J. S. Mill : it seems to admit of a very simple and irresistible contradic- tion from the following consideration : It is easy to give instances in which an invariable sequence takes place, and yet the two events which follow each other are obviously jiot connected as cause and effect. Take the case of lightning and thunder : the thunder follows the light- ning with invariable sequence, whether we chance to hear it or not, but the two are separate effects of the same cause acting under differ- ent conditions ; and no rightly instructed person could imagine that one was the effect of the other. Or suppose that you shout, and pro- duce two echoes from two rocks at different distances ; these echoes will satisfy the condition of invariable sequence, and yet will mani- festly not be related as cause and effect. Or, to put the case more generally, it is quite possible that a cause may j)roduce more than one
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effect ; and these effects being invariably connected will, by ignorant people, be regarded as cause and effect, which they will not be. In fact, the reference of one phenomenon to another as its cause, in con- sequence of invariable sequence, may have the same essential error in- volved in it as had the classical example of Tenterden Steeple and the Goodwin Sands.
"What is necessary in order that one thing shall be regarded as the effect of another, which may be called the cause, is not only that there shall be an invariable sequence, but also that it shall be possible to as- sert that the one could not take place without the other, or something equivalent. This invisible, impalpable chain between the one thing and the other must be postulated by the human mind : it constitutes the idea of cause ; every child knows perfectly well what it is, and the profoundest philosopher does not go far, if at all, beyond the knowledge of the child.
Let me support what I have been saying by a quotation from Whewell's *' Philosophy of the Inductive Sciences " :
TVe see in the world around us a constant succession of causes and eflfects connected witli each other. The laws of this connection we learn in a great measure from experience, by observation of the occurrences which present them- selves to our notice, succeeding one another. But in doing this, and in attending to this succession of appearances, of which we are aware by means of our senses, we supply from our mind the idea of cause. This idea, as we have already shown with respect to other ideas, is not derived from experience, but has its origin in the mind itself; is introduced into our experience by the active not by the passive part of our nature.*
And again Dr. Whewell writes :
That this idea of cause is not derived from experience, we prove (as in former cases) by this consideration : that we can malce assertions, involving this idea, which are rigorously necessary and universal ; whereas knowledge derived from experience can only be true as far as experience goes, and can never contain in itself any evidence whatever of its necessity. We assert that " every event must have a cause " ; and this proposition we know to be true, not only probably and generally, and as far as we can see ; but we can not suppose it to be false in any single instance. We are as certain of it as of the truths of arithmetic or geometry.t
Here is a true postulate ; and if to the postulate that every event must have a cause we add these postulates, (1) that causes in Nature are always of the same kind and always act in the same way, and (2) that no new causes come into existence, we should go a long way toward making the uniformity of Nature, if not axiomatic, at all events capable of tolerably simple and satisfactory demonstration.
But these latter postulates will perhaps scarcely be universally granted. I understand those disputants, who in the Metaphysical Society's discussion laid so much stress upon the duty of examining
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into the truth of alleged phenomena lying apparently outsiilc the circle of ordinary experience, to have argued that there might be causes of which ordinary physical science takes no account, and that you can not logically deny the occurrence of what may be called conveniently the " supernatural," unless you assert that the causes which are included in what we call Nature exhaust all ])o.ssible forms of causation. tSuch an assertion would probably be rash, even if we took into account only the results which may bo produced by the action of the human will. But so far as the ])hysical investigator, the scientific discoverer, the man of science in the ordinary sense of the ])]»rase, is concerned, he may consistently say that all causation of a spiritual or supernatural kind is outside his domain. lie may say, " I neither aflirm nor deny the i)ossibility of events and phenomena which are not according to the ordinary course of Nature. I am content to take what is called the uniformity of Nature as prescribing the limit of my inquiries" ; and he may be able to add, with Professor Huxley, that he has never yet found it to fail him. If it should fail him, the result might possibly be similar to that which mathematicians call the failure of Taylor's theorem, and might indicate, not that the theorem was faulty, but that in certain critical cases the ordinary law of the theorem would not apply.*
The discussion which precedes has been longer than I expected, but I could not well shorten it. Hitherto I have been chiefly engaged in what has been offered by others on the subject of the uniformity of Nature ; I now proceed to suggest a view which, if it fails to give the reader's mind as much satisfaction as it affords my own, will at least, I trust, be deemed worthy of some consideration.
Strict views concerning the uniformity of Nature appear to me to date from the period when Newton first showed that the motions of the heavenly bodies could be made the subject of mathematical calculations, or rather of dynamical, for I am not s])eaking of those which are merely empirical. Newton, in fact, founded what we now call physical astronomy. If we look a little back from this period, we find the opinions of men of the most educated class very loose on the sul>ject of Nature and Nature's laws. It is sufficient to refer to Sir Thomas Browne's belief, that intercourse was possible between human creatures and evil spirits,f and Sir INIatthew Hale's often-quoted opinions and consequent judicial action in the case of witchcraft. There was much in popular superstition, much even in orthodox re- ligious belief, and perhaps much in the tendencies of the human intel- lect, to suggest views of Nature which would now present insuper- able obstacles to minds even of ordinary jiowers and ]iroficicncy, but which presented no such obstacles in what may be called the pre-sci-
- There are some passages in pp. 217-219 of the Bishop of London's lectures to which
I would have referred had space permitted, f " Kcligio Medici ; " chap. xxx.
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cntific era of tlie world's history. Newton, or rather Newton as cle- velopod by La])lace and the French school of mathematicians, entirely changed the whole aspect of things. Laplace, with propriety, de- scribed his great work by the title of ' Celestial Mechanics ' : the pur- pose of the work, which it effected with singular skill, was the reduction of the whole system of the heavens to the condition of an ordinary mechanical problem — a problem, too, having the advantage that the bodies concerned are all moving in vacuo, and that therefore there are none of the difficulties of friction, resistance of the air, and the like, which interfere with the easy solution of terrestrial dynamical problems. To the mathematician the solar system is a set of small bodies, which for some purposes may be even regarded as particles, revolving in connection with one much larger and central body, under the action of mutual gravitation according to a certain simple law ; while the earth, regarded by itself and with reference to the phenom- ena of its own revolution, is a rigid, slightly oblate spheroid, the motion of which in given circumstances constitutes one of the prettiest prob- lems of rigid dynamics. It is difficult perhaps for any one, who has not gone through the study pesonally and practically, to conceive how completely to the mind of a mathematician the solar system resolves itself into a problem of bodies in motion in vacuo. But, as soon as the mind apprehends the solar system thus, it has found an instance of the uniformity of Nature upon a very large scale. The mathema- tician who is capable of solving the problem of the planetary motions, as Laplace and Lagrange solved it, or who knows anything of the motion of a rigid body revolving as the earth revolves, finds himself simply incapable of conceiving of anything but motion, according to fixed law, being found in the solar system ; the uniformity of Nature in this department presses itself upon him with a power which he can not resist.
A mathematician, for example, would find himself entirely pre- cluded from sympathizing, in the most distant manner, with the view expressed by Mr. Ruskin at the meeting of the Metaphysical Society. The standing still of the sun, of which Mr. Ruskin speaks so pleas- antly, means the stopping of the revolution of the earth, for the mo- tion of the sun is only the earth's revolution ; consequently, what is called the standing still of the sun involves tremendous dynamical consequences, an utter disruption of everything upon the earth's sur- face, a return of chaos, or I know not what. I am not criticising the expression as to the sun standing still, used in the book of Joshua without any attempt at scientific language. What the actual fact was to which the language used refers, and what was the actual phenom- enon, I can not undertake to say ; but if we adopt the phrase into the language of the nineteenth century, and in that language speak of the news of the sun standing still as a thing which need not sur- prise us, but which we have rather expected than otherwise, then I
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Ray that to tho matlieniatician tho language involves a necessary catastrophe, and that if tho nun did stand !<till, even fur a moment, no one would be left to tell the tale.
It is true that all men are not mathematicians, and that it is im- possible for a mind which has not studied physical science mathemati- callv fully to estimate the impression of contradiction and impossibili- ty produced upon the mind which has so studied by an allegation of any irregularity in the clock of Nature. Be it obser\'ed that the be- lief in the uniformity of such a phenomenon as the rising of the sun, or of the effect of the moon on the tides, or of such observed facts as precession and nutation, and many others, is to the mathematical physicist something different in kind from that which arises from mere experience. If you say that the sun has risen millions of times already, and therefore will probably, or almost certainly, rise to-mor- row, you offer a good presumptive argument ; but it is not the argu- ment which chiefly weighs with the man who knows what the rising of the sun means, and what would be the mechanical result of his fail- ing to do so. My belief, however, is, that the feeling of certainty as to natural phenomena, which such men as Laplace felt for the first time in human history, has percolated (so to speak) through the strata of human intelligence until it has become the common property of almost all. The whole aspect of Nature has been changed ; and many a man feels a persuasion of the existence of something which may be described as uniformity, and in virtue of which he questions or doubts or denies many things which would have been accepted as possible or probable in the seventeenth century, without knowing or being able to explain upon what his convictions rest.
Hence, according to my view, the uniformity of Nature, instead of being capable of being defended as a postulate, is, so far as it is true, the result of very hard scientific fighting. In the region of celestial mechanics it may be said to have gained absolute sway, because the motions of the heavens resolve themselves into the ordinary laws of mechanics, supplemented by the law of universal gravitation ; and from this region there is a very intelligible tendency to extend the assertion of the principle to other departments of scientific investi- gation. Such extension, however, must be made with caution ; even in the solar system itself, the moment we go beyond mechanics, all uniformity appears to vanish. "With regard to size, arrangement, density, in fact every element of planetary existence, variety, which defies all kind of classification, not uniformity, is the undoubted order of Nature.
There is a striking paragraph on this subject from the pen of no less a man than Alexander von Humboldt, which it may be well to quote in this connection. After speaking of the absence of all known law connecting the various planetary elements, their magnitudes, densities, etc., he proceeds thus :
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"We find Mars, though more distant from the Sun than either the Earth or Venus, inferior to them in magnitude ; being, indeed, tliat one of the long-known greater phmets which most nearly resembles in size Mercury, the nearest planet to the solar orb. Saturn is less than Jupiter, and yet much larger than Uranus. The zone of the telescopic planets, which are so inconsiderable in point of vol- ume, viewed in the series of distances commencing from the Sun, comes next before Jupiter, the greatest in size of all the planetary bodies; and yet the disks of these small planets (whose apparent diameters scarcely admit of measurement) are less than twice the size of France, Madagascar, or Borneo, llemarkable as is the small density of all the colossal planets which are farthest from the Sun, yet neither in this respect can wo recognize any regular succession. Uranus appears to be denser than Saturn ; and we find both Venus and Mars less dense than the Earth, which is situated between them. The time of rotation decreases on the whole with increasing solar distance, but yet it is greater in Mars than in the Earth, and in Saturn than in Jupiter. Among all the planets, the elliptic paths of Juno, Pallas, and Mercury have the greatest eccentricity, and Venus and the Earth, which immediately follow each other, have the least, while Mercury and Venus (which are likewise neighbors) present in this respect the same contrast as do the four smaller planets,* whose paths are so closely interwoven. The eccentricities of Juno and Pallas are nearly equal, but are each three times as great as those of Ceres and Vesta.t
I will not prolong the quotation, "but will add the following sen- tences, which contain the result which I wish to enforce :
The planetary system in its relations of absolute magnitude, relative position of the axes, density, time of rotation, and diflferent degrees of eccentricity of the orbits, has to our apprehension nothing more of natural necessity than the rela- tive distribution of land and water on the surface of our globe, the configuration of continents, or the elevation of mountain-chains. No general law in these respects is discoverable, either in the regions of space or in the irregularities of the crust of the earth. They are facts of Nature which have arisen out of the confiict of various forces acting under unknown conditions.^
In other words, from the point of view now under consideration there is no such thing as the uniformity of Nature.
Nevertheless, the instinct of seeking uniformity in other depart- ments, wjicn it has been discovered in one, and that an important department, is not only intelligible but is of the highest value as a help in the pursuit of knowledge. Professor Huxley, as we have seen, describes the principle as a working hypothesis, which has never failed him ; and, so regarded, it can lead to no error, and it may lead to the discovery of new truth. If uniformity be wrongly assumed, the results obtained may be erroneous, or they may not ; examination and experiment will show which they are ; a working hypothesis may al- ways be freely granted to an investigator, but it must not be con- founded with a postulate upon which the whole body of science rests.
Let me illustrate the character of a working hypothesis by a second
- This was written when only four asteroids were known. While this article is
passin? through the press the discovery is announced of the 249th asteroid ! f " Cosmos," vol L (Sabine's translation). % ^^^^-
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reference to tlie discovery of tlie planet Neptune. Two working hypotheses were necessary in this case. First, tiiere was the great hypothesis of gravitation according to the Newtonian law. lint, secondly, it was necessary for the purpose of the calculation to make some assumption concerning the supposed planet. It was, accord- ingly, assumed that Uode's empirical law of planetary distances was true, and that, if the planet existed, its distance would be given by this law. The position of the planet was determined by the remark- able calculations of Adams and Leverrier ; and what was the result ? That the Hrst hypothesis was confirmed, if it needed confirmation, and that the second was exploded, when the distance of Neptune came to be determined by actual observation. Thus a working hy- pothesis was proved to be false ; but no harm was done. Neptune was discovered, though his distance had been wrongly assumed ; the working hypothesis had fortunately been near enough to the truth for the pur- pose in hand, and, having served that purpose, it could be flung away.
But in speaking of a working hypothesis it should be carefully borne in mind that the very epithet xcorking indicates limits within which the work must take place. The hypothesis of the uniformity of Nature, being founded upon or suggested by the discovery of uni- formity in a certain department, must be carefully confined to similar departments, or, at all events, must be regarded with suspicion if it goes beyond them. "We have already seen that if an astronomer, from the uniformity of mechanical action in the solar system, should con- clude that there was some kind of uniformity in the configuration and the relations of the elements of the system, he would find him- self deceived. Speculations concerning such uniformity are neverthe- less very tempting. Kepler, as will be remembered, could not resist them, and got into some quagmires in consequence. But the temptation must be resisted ; an assumed uniformity may lead to serious errors, if it goes beyond the strictly physical region to which it belongs.
And this view of the matter leads, as it seems to me, to sound con- clusions, with regard to the relation in which the truth of the uniformity of Nature stands to truths, or supposed truths, of a different kind.
Take, for example, the case of alleged apparitions. I imagine that the tendency in the minds of not a few among us is to ignore appa- ritions utterly and completely. They are supernatural, and that is enough ; they do not conform themselves to the recognized laws of mechanics, optics, acoustics, motion. This is a rebound from the old facility in accepting tales of demonology and witchcraft in pre-scien- tific times, and it has much to say for itself. Nevertheless, it is scarcely philosophical, and is in no wise demanded by the requirements of sci- ence and the conditions of scientific progress. A man may be per- fectly orthodox in his physical creed, and yet may admit the weight of evidence in favor of certain alleged phenomena which will not square themselves with physics. Such alleged phenomena are not necessarily VOL. xxnii. — 17
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in contradiction to physical truth, thoy lie rather in another plane ; they are like two lines or curves in space, Avhich do not meet, and there- fore can not cut each other. There are matters of the highest moment which manifestly do lie outside the domain of physical science : the possibility of the continuance of human existence in a spiritual form after the termination of physical life is, beyond contradiction, one of the grandest and most momentous of possibilities, but in the nature of things it lies outside physics. Yet there is nothing absolutely absurd, nothing which contradicts any human instinct, in the supposition of such possibility ; consequently, the student of physical science, even if he can not find time or inclination to look into such matters himself, may well have patience with those who can. And he may easily afford to be generous ; the field of physical science is grand enough for any ambition, and there is room enough in the wide world both for physical and for psychical research.
In truth, a wide-spread rebellion among some of the most thought- ful of mankind must be the result of any attempt to press the supposed principle of uniformity to the extent of denying all facts and phe- nomena which do not submit themselves. Religious faith is necessarily conversant with such facts and phenomena ; and though even here a familiarity with the conclusions of science may be useful in steadying the mind and fortifying it against superstition, still there are suj^er- natural truths bound up with the Christian creed, toward which it behooves all to bow with respect, and which can not be refuted by any appeal to the uniformity of Nature.
For Nature can only be uniform when the same causes are at work ; and to declare an alleged fact to be incredible, on the ground that it does not conform to the natural order of things, can only be reasonable upon the hypothesis that no new influence has been introduced in ad- dition to those which the natural order of things recognizes. But such an influence may be found in the action of will, or of some spirit- ual energy which does not exist in the ordinary natural order.
For example, it would be unwise absolutely to deny on a priori grounds the history of the stigmata of St. Francis of Assisi. There are not wanting examples to show that physical results of a remark- able kind can be produced by abnormal and excessive action of the affections, and feelings, and imagination. Recently recorded cases seem to invest even with a somewhat high probability the alleged ex- perience of St. Francis.
I am not of course committing myself to any opinion as to the spiritual corollaries which may follow from an admission of the reality of the stigmata ; one person may say that they have great religious significance, another that they are a curious instance of the physical effect of the imagination. I only argue that they must not be at once brushed away in deference to some supposed law of uniformity.
Still less is it wise to deny the possibility of events, recorded in
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the life of one greater tlian St. Francis, on the like ground. I am not going into the argument concerning the miracles and resurrection of the Lord ; but 'I wish to suggest that if the potency of a divine will be admitted, we have in the case of these events to take account of a power which does not present itself in the discussion of natural phe- nomena. We may well as philosophers admit, in consideration of the special circumstances of the case, the possibility of these supernatural facts, while prizing the principle of uniformity as a working hypothe- sis, or as more than this. For in truth even the action of the ordinary human will introduces strange breaches of uniformity into Nature. Conceive some observer endowed with human scientific faculties con- templating this earth of ours in the pre-human period. He sees the continents covered with forests, beasts of all kinds disporting them- selves in the same, a great vigor of vegetable and animal life both in the sea and on the dry land. But all is absolutely wild, not a single glimpse anywhere of human purpose and contrivance. Suppose our observer to speculate upon the future of this scene of life and activity by the help of the working hypothesis of the uniformity of Nature, of which we will liberally allow him the use out of the scientific reper- tory of our own times. Would it be possible that this working hy- pothesis could present to his view, as a possible future of the globe, anything essentially different from what he could then see ? The limits of land and water might have been observed to vary, and further variation might be anticipated ; volcanic action would have been seen to be very active, and it might be expected that volcanoes would still be a potent agent ; nay, I will even suppose that an observer is keen enough from his observations to deduce the theorj" of evolution, and 80 to expect that the flora and fauna which he witnesses are in process of transformation into something higher ; but could he possibly, in his happiest moment, and when his genius was highest, ever have con ceived or guessed the change which would come upon the globe when man appeared as the head and crown of the creation ? It is not that man would be a stronger, or more active, or more crafty beast, than had ever appeared before, but that he would be a new creature alto- gether ; a creature with plans and purposes of his own, capable of say- ing, " I intend to do this or that, and I will do it" ; a creature, in fact, with a will which, joined to an intelligence infinitely higher than any- thing exhibited before, would enable him to treat the earth as his own, to subdue the powers of Nature, and fashion the earth's surface after his own pleasure ; which also would make him a moral agent, and so a creature different in kind from all those which had preceded him. This, however, is not the point upon which I intend to dwell now ; what I wish to point out is, that the appearance of man upon the earth would break to fragments any theory which an observer might have formed with the aid of the working hypothesis of the uniformity of Nature. The forests disappear, except so far as man finds them con-
�� � 26o THE POPULAR SCIEXCE MOXTIILY.
vcnient ; the land is tilled ; the rivers are tamed ; houses are built ; ships tioat upon the sea ; everything is regarded with reference to human comfort, and the will of man has utterly transformed the whole surface of the globe. The uniformity of Nature, as Nature had been known or manifested hitherto, is altogether set aside by the action of the will of man.
These examples may be sufficient, or at all events may helj), to show the manner which the hypothesis of the uniformity of Nature must be regarded in order that it may express the truth. For my own part, I have no desire to speak lightly of it, or to despise it as a scientific guide. I have no sympathy with that opinion of Cardinal Newman, quoted by Dr. Ward at the meeting of the Metaphysical Society, to the efifect that England would be in a far more hopeful condition if it were more superstitious and more bigoted. When he adds " more disposed to quail beneath the stings of conscience, and to do penance for its sins than it is," I allow that the words may admit of a wholesome meaning ; but superstition, if I understand what is meant by the word, is an immeasurably and unutterably evil thing : it is the substitution for truth of that which is not truth ; it is something which, from its possible poetical accompaniments, may be tolerable to man, and nevertheless must, as I conceive, be infinitely intolerable to God. But there is no occasion to sigh for a little more superstition, in order to counteract the evils which may arise from a one-sided view of Nature ; nor are superstition and bigotry the best guides to true pen- ance : the thing really to be desired is a symmetrical and equal-handed dealing with human and divine knowledge. In the one department, the uniformity of Nature may be accepted as a valuable working hy- pothesis ; in the other, we contemjilate God without any hypothesis at all, as the Author and original Cause of Nature, of whose will uni- formity and variety are equally and co-ordinately the expression and the means of manifestation to human intelligence.
To sum up the views which I have endeavored to express in this pap>er : I trace the belief in the principle, described by the phrase "the uniformity of Nature," to the direct and indirect influences of the successful application of mathematics to the physical theory of the solar system. The principle so established may be used as a working hypothesis in physical investigations, so far as it predisposes us to seek for law and order in all parts of creation. But it must not be dealt with as an absolutely true principle, if for no other reason at least for this, that it has not been found practicable to define its meaning with precision. And especially we must take care not to assume it even as an hypothesis, except in cases in which it is quite clear that nothing but physical causes are concerned. Which last consideration should be regarded as a warning that the introduction of the principle into theological questions may very possibly lead to most erroneous con- clusions. — Nineteenth Centitry.