Influence And Method Of Physics
( Originally Published 1913 )
THE very destination of Positive Philosophy being that of influencing the whole intellectual system of man, who moves through life by its aid, Comte's summary indication of the part played by Physics in that action must not be omitted.
In the first place, its influence is necessarily less profound than that of the two terminal sciences, Astronomy and Biology. These two sciences standing at opposite extremes, directly determine our ideas respecting the two universal and correlative subjects of all our conceptions the world and man ; and hence, from their very nature, they must spontaneously influence human thought in a more decided way than can be done by the intermediate sciences, Physics and Chemistry, however indispensable the intervention of the two latter may be. The influence of Physics and Chemistry, however, on the general development and the definite emancipation of human intelligence, is nevertheless decided. To speak only of Physics, it is evident that the fundamental character of absolute opposition between positive philosophy and theology, or metaphysics, makes itself very strongly felt, although it is less complete than in the case of Astronomy, by reason of the inferiority of Physics in scientific perfection. For this comparative inferiority, of which vulgar thinkers are little sensible, we doubtless have a full equivalent, so far as the present question is concerned, in the much greater variety of the phenomena embraced by physics. In, fact, the intellectual history of the few last centuries makes it manifest that this science has been the principal scene of the general and decisive struggle of the Positive spirit against the Metaphysical ; in astronomy, the dissension as been less marked, and there positivism has triumphed almost spontaneously, except on the subject of the earth's movement.
There is another important fact to be noticed here. It is in Physics that natural phenomena first begin to be really modifiable by human intervention. This power of modification is impossible in astronomy; but we shall see it manifesting itself more and more in all the sciences of the encyclopedical series. If the extreme simplicity of astronomical phenomena had not necessarily permitted our carrying scientific prevision in their case to the greatest degree of exactness, it would have followed from the impossibility of our interfering in any way in their accomplishment, that their radical enfranchisement from all theological and metaphysical supremacy would have been a difficult process. But perfect prevision effectually served this end in a different way from the small virtual action of man upon all the other phenomena of nature. As respects the latter, on the contrary, this action, however limited it may be, obtains, by way of compensation, a high philosophical importance, on account of our inability to bring the rational prevision of them beyond a slight degree of perfection. The fundamental character of all theological philosophy is to conceive phenomena as subjected to supernatural volition, and, consequently, as eminently and irregularly variable. Now, the public cannot enter into any profound speculative discussion respecting the superiority of the different philosophical points of view; and those theological conceptions can only be subverted finally by means of these two general processes, whose popular success is infallible in the long run :
1. The exact and rational prevision of phenomena ;and 2. the possibility of modifying them, so as to promote our own ends and advantages.
The former immediately dispels all idea of any " directing volition ;" and the latter leads to the same result under another point of view, by making us regard this power as subordinated to our own. The first process is the more philosophical, and most easily carries popular conviction with it, when it is completely applicable, which, however, has scarcely been the case hitherto, exec et 'the celestial phenomenas but the second, when its reality is very evident, meets no less necessarily with universal assent.
Illustrations will occur in abundance to any well stored memory. I will mention, as an obvious and striking example, the destruction of the theological theory of thunder by Franklin's discovery. If man could thus take the lightning in his hand, and direct its course as he pleased, it could not long be believed to be the flashing wrath of a deity !
Passing from this topic to that of the Method of Physics, considered in their hierarchical position, Comte bids us remember that the speculative perfection of a science is to be principally measured by these two distinct but corelative properties coordination and power of prevision ; the latter being the most decisive criterion, as it is the principal object of every science.
In the first place, whatever may be the future progress of Physics, they must evidently continue, under both points of view, very inferior to Astronomy, owing to the variety and complexity of their phenomena. In lieu of that perfect mathematical harmony and unity which we have admired in the science of the heavenly bodies, Physics present us with numerous branches almost completely isolated from each other, and having frequently no other than a feeble and equivocal connection between their principal phenomena. And then, instead of the rational and precise prevision of celestial events at any period whatever, made from a very small number of direct observations, our foresight here is quite limited in its range, and, when certainty is desired, scarcely ever admits of our leaving present circumstances out of view.
For similar reasons, the speculative superiority of Physics over the rest of natural philosophy is equally incontestable. We may also observe that the philosophical study of Physics, regarded as a general means of intellectual education, possesses a special utility, not to be found elsewhere to the same extent ; it enables us completely to apprehend the fundamental art of Experiment, which is particularly adapted to physics. It is there that true philosophers, whatever the peculiar object of their habitual pursuits, must always learn what constitutes the true experimental spirit ; what are the characteristic conditions requisite in experiments which are capable of showing unequivocally the actual laws of phenomena; and finally, how to form a just conception of the ingenious precautions by which we may prevent any interference with the results of a process of such delicacy. Every one of the fundamental, sciences presents the essential characteristics of the Positive Method, which are necessarily manifested in them in a degree more or less decided : but besides this, each of them as naturally shows some philosophical indications belonging peculiarly to itself, as we have already remarked in the case of astronomy; and it is always at their source that such conceptions of universal logic ought to be examined.
It is to Mathematics alone that we are indebted for our knowledge of the elementary conditions of positivism. Astronomy characterises with precision the true study of nature ; Physics specially present us with the theory of Experiment ; it is from Chemistry that we must borrow the general art of Nomenclature ; and finally, the science o Organised Bodies can alone unfold to us the true theory of Classifications.
Newton's assertion, Hypotheses non fingo,I make no hypothesis, has been incessantly repeated by men who fancy themselves Baconian thinkers when they restrict their incompetence to what they call " facts." No reader of these pages need be told that such ideas of science are utterly irrational. Newton himself gives it no countenance. His own great discovery was an Hypo-thesis at first, and only became a Theory after verification. Kepler made nineteen hypotheses respecting the form of the planetary orbits, and abandoned them one by one, till he settled on the elliptical form, which, on verification, proved correct, and then was no longer an hypothesis.
Every one who has made any original scientific researches must have a vivid sense of the indispensable utility of Hypothesis as an artificial aid, accompanied by an equally vivid sense of the necessity of distinctly understanding its purpose and limits; and to this end I emphatically urge the reader to study what Comte and John Stuart Mill has written on the subject. Mill's Logic the reader has, or ought to have, at hand. Comte teaches thus : A law of nature can only be discovered by Induction or Deduction. Often, however, neither method is of itself sufficient without our previously making temporary suppositions regarding some of the very facts of which we are in search. This indispensable mode of proceeding has been most fruitful in its results ; but, from neglect of the condition on which it can be rightly used, the progress ' of true science has been much obstructed. This condition, but vaguely analysed as yet, may be thus stated : that we must never imagine any hypotheses which are, not by nature susceptible of a positive verification sooner or later, and which shall have exactly that degree of precision ascertainable in the study of the corresponding phenomena. In other words, truly philosophical hypo-theses must always present the character of simple anticipations of what experience and reasoning are capable of at once discovering when the circumstances of the problem are more favourable.
But if we would pretend to attain, by means of an Hypothesis, anything that is in its nature altogether inaccessible to observation and to reason, we should overlook the fundamental condition of all Hypothesis ; and our supposition, transcending the real sphere of science, would become misleading and dangerous.
It would become dangerous, because every positive thinker agrees that our scientific inquiries are restricted to the analysis of phenomena, to discover their Laws, and in no sense to discover their Causes, essential or final. And how should a pure supposition, such as an Hypothesis, be possessed of a deeper plummet line to fathom the unfathomable ? Therefore every hypothesis which traverses the limit of positive science can only lead to interminable discussion, never to solid agreement.
The different hypotheses still employed by natural philosophers are clearly distinguishable into two classes : the one, as yet small in extent, simply refers to the laws of the phenomena : the other, which plays a much more extended part, relates to the determination of the general agents supposed to produce the different kinds of phenomena. Now, according to the rule just laid down, the first class is alone admissible ; the second, essentially chimerical, has an anti-scientific character, and can only obstruct the real progress of physics. In astronomy, the first kind of hypothesis is alone employed; the use of the second was long ago exploded. We no longer suppose the existence of chimerical fluids to explain the movement of the heavenly bodies. Why, then, in physics use hypotheses without the requisite precautions, and imagine fluids and ethers, invisible, intangible, imponderable, and inseparable from the substances to which they impart their virtues, in order to explain the phenomena of heat, light, electricity, magnetism ? The very fact that the existence of these pretended fluids is,from their nature, incapable of negation or affirmation, shows that they are beyond the reach of positive control. You might as well admit the existence of the elementary spirits of Paracelsus, of angels, and of genii ! The assumption of these Entities in science, so far from helping to explain phenomena, has the very reverse effect ; it increases the number of things requiring explanation. For whence come the properties of these fluids? On what do they depend? It is evident that they demand explanation as much as the phenomena they are introduced to explain; they are the tortoise back upon which the Indian's world is supposed to rest ! Newton could not conceive attraction otherwise than through the agency of an ether. No one believes in that attracting medium now; yet men of science, especially in England, will be up in arms at the heresy of supposing light, heat, or electricity, can be robbed of their mysterious fluid ! Because it will sound heretical, I strengthen Comte's position by the following passage from John Mill :
" The prevailing hypothesis of a luminiferous ether I cannot but consider, with M. Comte, to be tainted with the same vice. It can never be brought to the test of observation, because the ether is supposed wanting in all the properties by means of which our senses take cognizance of external phenomena. It can neither be seen, heard, smelt, tasted, nor touched. The possibility of deducing from its supposed laws a considerable number of the phenomena, of light is the sole evidence of its existence that we have ever to hope for ; and this evidence cannot be of the smallest value, because we cannot have, in the case of such an hypothesis, the assurance that if the hypothesis be false it must lead to results at variance with the true facts.
" Accordingly, most thinkers of any degree of sobriety allow, that an hypothesis of this kind is not to be received as probably true because it accounts for all the known phenomena; since this is a condition often fullfilled equally well by two conflicting hypotheses ; and if we give ourselves the license of inventing the causes themselves as well as their laws, a person of fertile imagination might devise a hundred modes of accounting for any given fact, while there are probably a thousand more which are equally possible, but which, for want of anything analogous in our experience, our minds are unfitted to conceive. But it seems to be thought that an hypothesis of the sort in question is entitled to a more favourable reception, if, besides accounting for all the facts previously known, it has led to the anticipation and prediction of others which experience afterwards verified ; as the undulatory theory of light led to the prediction, subsequently realized by experiment, that two luminous rays might meet each other in such a manner as to produce darkness. Such predictions and their fulfilment are, indeed, well calculated to strike the ignorant vulgar, whose faith in science rests solely on similar coincidences between its prophecies and what comes to pass. But it is strange that any considerable stress should be laid upon such a coincidence by scientific thinkers. If the laws of the propagation of light accord with those of the vibrations of an elastic fluid in as many respects as is necessary to make the hypothesis a plausible explanation of all or most of the phenomena known at the time, it is nothing strange that they should accord with each other in one respect more. Though twenty such coincidences should occur, they would not prove the reality of the undulatory ether ; it would not follow that the phenomena of light were results of the laws of elastic fluids, but at most that they are governed by laws in some measure analogous to these ; which, we may observe, is already certain, from the fact that the hypothesis in question could be for a moment tenable. There are many such harmonies running through the laws of phenomena in other respects radically distinct. The remarkable resemblance between the laws of light and many of the laws of heat (while others are as remarkably different,) is a case in point. There is an extraordinary similarity running through the properties, considered generally, of certain substances, as chlorine, iodine, and brome, or sulphur and phosphorus ; so much so that when chemists discover any new property of the one, they not only are not surprised, but expect to find that the other or others have a property analogous to it. But the hypothesis that chlorine, iodine, and brome, or that sulphur and phosphorus, are the same substances, would, no doubt, be quite inadmissible.
"I do not, like M. Comte, altogether condemn those who employ themselves in working out into detail this sort of hypotheses ; it is useful to ascertain what are the known phenomena to the laws of which those of the subject of inquiry bear the greatest, or even a great analogy, since they may suggest (as in the case of the luminiferous ether it actually did) experiments to determine whether the analogy which goes so far does not extend still further. But that in doing this, men should imagine themselves to be seriously inquiring whether the hypothesis of an ether, an electric fluid, or the like, is true ; that they should fancy it possible to obtain the assurance that the phenomena are produced in that way, and no other ; seems to me, I confess, as unworthy of the present improved conceptions of the methods of physical science, as it does to M. Comte. And at the risk of being charged with want of modesty, I cannot help expressing astonishment that a philosopher of the extraordinary attainments of Mr. Whewell should have written an elaborate treatise on the philosophy of induction, in which he recognises absolutely no mode of induction except that of trying hypothesis after hypo-thesis until one is found which fits the phenomena ; which one, when found, is to be assumed as . true, with no other reservation than that if on re-examination it should appear to assume more than is needful for explaining the phenomena, the superfluous portion of the assumption should be cut off. It is no exaggeration to say, that the process which we have described in these few words, is the beginning, middle, and end of the philosophy of induction as Mr. Whewell conceives it. And this without the slightest distinction between the cases in which it may be known beforehand that two different hypotheses cannot lead to the same result, and those in which, for aught we can ever know, the range of suppositions, all equally consistent with the phenomena, may be infinite"
Comte clearly shows how this conception of Ethers is only a remnant of the Metaphysical stage ; and remarks that the metaphysical origin of this false method of proceeding can be easily detected by every impartial inquirer who will consider the fluids as having taken the place of the entities, the transformation of the latter being simply by materializing them. What, in reality (put what interpretation on it we will), is Heat, conceived as existing apart from the heated body ? Light, independent of the luminous object ? Electricity, separated from the electrical body? These are evidently nothing but pure Entities, just as much as Thought is, when considered as possessing an existence independent of the thinking body ; or Digestion when isolated from the digesting body ! The only difference distinguishing them from these ancient scholastic Entities is this, that these essentially abstract existences have been replaced by imaginary fluids, whose corporeity is very equivocal, since, by their essential definition, we deprive them of all qualities capable of characterising any kind of matter whatever. Indeed, we do not even leave room for our regarding them as the ideal limit of a gas indefinitely rarefied.
It may . serve perhaps to clear up some of the con-fusion darkening this subject, if I allude to a distinction necessary to be made in treating of the hypothesis of a luminiferous ether. The undulatory hypothesis as regards the process,—i. e. as a Method or path along which the phenomena travel, is not only admissible, it is admirable ; but in saying this, we do not imply an admission of the hypothesis of the existence of an Ether whose undulations produce light. The phenomena of light may be due to undulations ; but that they are undulations of an Ether cannot be proven, unless the existence of the Ether itself can be proven, and by the very terms of its definition we cannot prove an Ether.
The fundamental character of metaphysical conceptions is to look on phenomena as independent of the objects which manifest them, and to attribute to the properties of each substance an existence distinct from its own. What matters it, then, whether we make spirits or fluids of these personified abstractions ? Their origin is always identical. It constantly springs from that inquisitiveness into the hidden nature of things, which marks, in every race, the infancy of the human mind, and which first inspired the conception of gods ; these gods were subsequently transformed into spirits and entities, and have finally been transformed into imaginary fluids.
Agreeably to the law of development, Physics had to pass through this transitional stage of metaphysics. Astronomy did the same. The astronomical metaphysical suppositions of Descartes, which were as ably supported as similar suppositions in Physics have been, gave way when the true nature of positive Astronomy was established by the discoveries of Newton. In like manner metaphysical notions have been driven from the more advanced parts of Physics. No man of note has, since the days of Galileo, propounded an hypothesis to explain the fall of bodies. But the less advanced parts of Physics, such as Light and Electricity, still suffer from this metaphysical influence. They do so from the same causes which affected the others, and will, like them, be gradually emancipated.
Comte next occupies himself with the division of Physics into its principal branches. This division is, of course, based on the degree of generality of corresponding phenomena, on the extent of their complication, their relative states of speculative perfection and also their mutual dependence. Accordingly, the science of the phenomena of weight ( Barology as he calls it,) ranks as the first branch by universal consent; and, on the other hand, the science of Electrical phenomena ranks last. The former is most allied to Astronomy ; the latter forms a natural transition to Chemistry. They are at the two extremes of Physics, not only as respects generality and the other qualities just mentioned, but also in regard to their present states of positivity. Between these two extreme terms we have, first, Thermology, next Acoustics, and then Optics.
Having thus indicated the main points in his general considerations on Physics, I have passed over that portion of the ground which, from its abstract nature, will have had less interest to minds not specially versed in these subjects, than those which are to follow.