Part 6

Energy is the term now employed to designate every form of power belonging to the physical world capable of doing work, and of being estimated according to the comparative amount of work it can perform. The whole phenomena of motion thus belong to this department of inquiry. The first distinction here has been described as the difference between _energy of position_ and _energy of motion_.[AG] Both of these must be taken into account in order to have a full view of the facts. ENERGY OF POSITION, is illustrated by a water-head, or reservoir, where an accumulation of water is laid up in store, ready to be drawn upon for motive power when machinery set up in a position somewhat lower is to be brought into action and made to do the work for which it has been constructed. ENERGY OF MOTION is seen when the storehouse of water is opened and the rush of the current sweeps along the prepared channel descending upon the great wheel, which sets in motion the whole machinery. In such a case as this, the amount of work done by the revolutions of the great wheel is an exact measure of the amount of water which has passed to a lower level. Or let us suppose there is only a limited supply in the water-head, and that there are no feeders, but that the streamlets and springs from which it is supplied, have ceased to flow, and let us suppose that the mill comes to a stand because of failure of motive power, the amount of work done up to that moment is the measure of the energy stored in the water-head before the sluice was opened. This illustration indicates the mode of calculation to be applied to energy in all its forms, including the great forces of nature, before which human power is as nothing. Taking thus the correlatives position and motion, we may regard the former as preparation for the latter, for, as Professor Balfour Stewart has said, "It is the fate of all kinds of energy of position to be ultimately converted into energy of motion."[AH] On this account, energy of motion most naturally exemplifies what we understand by energy; but on the other hand what has been called the energy of position must be regarded as a power distinctly calculable. If a stone be thrown into the air, the energy expended in propelling it to a certain height, is the exact measure of the energy expended in its descent. There is no need for entering here upon the calculations of the relation between energy and velocity, showing the exact proportion of the one to the other, or the ratio of increase according to velocity, which is expressed in the formula "that the energy varies as the square of the velocity," giving us an exact measure of force.

Aided by the conceptions of position and motion, we take the next step when we advance to _transmutation or conversion of energy_. What is made visible to us by motion is the transference of energy from one object or portion of matter to another. And this is the sole explanation of what occurs. There is no such thing known to physical science as the origin or creation of energy; all that is recognized is the disappearance of energy from one position and its appearance in another. If work has been done, energy was somewhere stored capable of doing it; a transmutation has taken place; and the work accomplished is the record of the process. In recognition of this, every machine is merely a more or less skilful contrivance for transmuting energy into a form more convenient or suitable for human purposes. The intelligence of man simply recognizes the law of transmutation, and deals with the problems which arise connected with the mechanical arrangements facilitating the process.

We next advance a further step, only to embrace another phase of the same truth,--the complement of what has been already stated,--that is, the _conservation of energy_. As we have seen, all that appears in motion, is transmutation or conversion of energy; accordingly it follows, that there is change of position, but no destruction of energy, or absolute disappearance of it from existence. This generalization is illustrated by a most attractive series of observations, introducing to a fuller knowledge of the laws of heat. The natural tendency of ordinary observation is to favor the opinion that when work has been done, energy is spent or lost. And this popular notion, which has a kind of accuracy, in so far as it is needful to make fresh draughts upon available resources, is favored by reference to the economy of our bodily existence constantly renewing its demand for fresh food supply. But this popular tendency is easily explained by the circumstance that ordinary observation makes much more account of the phenomena of motion, than of the development of heat as a direct consequence. The machinist can not, indeed, afford to make little of the consequences of friction; but the ordinary observer makes much more of mass, and complication of mechanical contrivance, and velocity of movement. From this he passes easily to the fabric, or other production, sent forth; and then he may occupy himself with calculations bearing on the expenditure for coals and labor, along with tear and wear of machinery. But scientific observation has concentrated much more on the evolution of heat, and out of this has come the completed theory of the laws of energy. In this way, it became matter of distinct calculation that friction and percussion convert energy into heat.

Along with these observations we have to remark upon an attendant conclusion, which has an important bearing on all speculation concerning the destiny of the universe. I refer to the fact that transmutation of energy involves a deterioration and dissipation of energy. As in the history of energy, improved position adds to the advantage for the doing of work, so transmutation tends to diminish the advantage or utility of the energy for human purposes. Thus the energy expended in working a machine gives return in a product of recognized value, but the energy spent in contending with friction generates heat which is of no practical value in respect of accomplished work. Or as the latter fact has been stated by Professor Balfour Stewart, friction proves "itself to be, not the destroyer of energy, but merely the converter of it into some less apparent, and perhaps less useful form."[AI] In this connection, scientific observation was directed upon the appearance of heat simultaneously with the disappearance of visible energy. Gradually the conception dawned upon scientific observers that _heat is a form of motion_, and this has found general acceptance, although it is impossible to give direct proof of the doctrine. The conclusion has been supported by all the experiments of Davis, Rumford, Joule, Colding, and Helmholtz. This conception having been launched as to the probable explanation of heat, it immediately found, in accordance with the analogies of scientific thought, a greatly extended circle of application. Light and sound came to be classified with heat, as only different forms of motion. It would involve too extended a range to include here a detailed account of these experiments, or to consider what is involved in dissipation of energy, as bearing upon a still wider aspect of the order of things in the universe. I must, therefore, be content with the reference just given to the conception of heat as a form of molecular motion; and in doing so may revert to the consideration already adduced, that this is another doctrine of scientific _belief_, of which there is a constant tendency to increase the number, as science widens the range of its inquiries and speculations.

The outstanding general results of science as to the nature of energy are now before us. All observations concerning motion only present to view transmutations of energy, all of them imply that there is no such thing as the origin of energy, and no such thing as its extinction. There is indeed a constant tendency towards the degradation of energy, and a constant equalizing process which may bring to an end the present order of things in the universe. But the leading scientific conception with which we have specially to deal is that expressed in the phrase, "_Conservation of energy_," which must be regarded as completing our view of inorganic existence along with the other doctrine of the indestructibility of matter. As Professor Tait has expressed it,--"The grand principle of conservation of energy, which asserts that no portion of energy can be put out of existence, and no amount of energy can be brought into existence by any process at our command, is simply a statement of the invariability of the quantity of energy in the universe,--a companion statement to that of the invariability of the quantity of matter."[AJ]

The position is now reached at which it becomes possible to combine the results of scientific research as to matter and energy into a harmonious unity, with which to test the view of the world recognized by religious thought. Religion as an intelligent and devotional acknowledgment of a Supreme Being, involves a very clear and definite conception concerning the origin of the universe and its continuance. What is thus implied will be best indicated by negative as well as positive statements, in some such form as the following. First, _negatively_, the world we inhabit does not carry _within it_ any explanation of the origin of its own existence; that is to say, neither the materials existing, nor the forces operating, are sufficient to account for its origin; neither can it have had existence without beginning. In _positive_ form, the universe can be accounted for only by that which _transcends_ itself; the supernatural is the key to the natural; Nature is a creation to be attributed to an Intelligent First Cause.

Are science and religion here in harmony in the form and measure compatible in the circumstances? This qualified and guarded form of the question is obviously required, for religious thought does not profess to be scientific, or in any sense authoritative as to the phenomena of nature, that is, as to the facts which observation alone can ascertain, or as to the immediate causes by which these facts are to be explained. On the other hand, science is exclusively a knowledge of nature, consisting of methodized observations concerning distinct orders of facts, and rational inferences founded upon these. It can not in true sense be concerned with the supernatural, but can only present conclusions as to the order and processes of nature, which by subsequent and independent exercise of our intelligence may be contemplated in their relation to the conception of the supernatural, as Intelligent First Cause. This subsequent exercise of thought, whether critical or constructive, is more properly the task of philosophy, in prosecution of those reflective and speculative exercises, which, proceeding from scientific conclusions as accepted data, consider their intellectual value as contributing towards a theory of the universe. Scientific men will, of course, more or less readily pass over to take some share in such philosophic speculation; just as religious men, purely under the impulse of religious interests, will be more or less disposed to do, in proportion to the range of their intellectual life. What is here said is not intended as an argument for any restriction upon such speculation on the part either of scientific or of religious men, for such questions are common property, and the arguments bearing upon them are to be tested by all. But it is of some consequence, specially in the present unsettled and sensitive state of the public mind, that it be clearly recognized that science is not itself responsible for the thoughts of scientific men on these questions; and that religion is not responsible for the thoughts of religious men upon them. Science can not determine any thing as to a philosophy of the supernatural, any more than religion can determine any thing as to a science of nature. Whether we take the violent and even passionate antipathy to any acknowledgment of the supernatural which is found in the Essays of Clifford, or the profoundly reverential acknowledgment of the Deity in the writings and life of Faraday, science is to be credited with neither. And so in like manner, when we have violent denunciations of science professedly in the name of religion, or intelligent appreciation of its high value from accredited upholders of religious truth, religion itself is to be credited with neither the one nor the other. This is a matter which comes within the range of ordinary intelligence. It may indeed belong to philosophy to formulate and develop the arguments in strict harmony with the recognized laws of mind; but it belongs equally to all men to estimate the general sweep and range of acquired knowledge as to the structure and order of the universe, as bearing upon the more general conceptions to be rationally entertained regarding its government. With this branch of the subject, ordinary thought may readily deal without entanglement in technicalities.

There is as we have seen a _duality_ of existence in the inorganic structure of the world, and a continual succession of changes, on account of the interaction of these two. Different forms of matter stand in different relations; and these relations are being constantly interchanged by the transmutation of energy. Thus taking the world as presented to us, it has a constitution which requires for its explanation that we go beyond every thing to be found within itself. The matter in the universe can not account for the energy; nor can the energy account for the matter; and the relations between the two must find explanation in something higher than both. What their source may be, science is incapable of telling; it can not contribute towards satisfying the requirements of the law of causality in view of the mutual relations of matter and energy which it has itself revealed. But equally by what it has revealed, and by acknowledgment of its inability to transcend the limits of its own discoveries, does it present harmony with religious thought in the form and measure in which it is possible that such harmony could be manifested. Discovering the objective existence of matter and energy, and the laws in accordance with which the latter acts upon the former, it presents an unsolved problem affording the most direct and positive testimony possible to science in support of the existence of a First Cause, transcending the universe itself. How matter and energy came into being, it can not tell; but it most explicitly declares that by no power existing and operating within range of observation is it possible either to add to the sum of existence, or in the least degree to diminish it. Religious thought could expect nothing more direct and explicit in the form of scientific testimony as confirmation of its fundamental position. Scientific thought while dealing with inorganic existence could not, even by a single line of approach, be brought nearer to the actual support of religious belief.

Here the question may be raised,--May not the world have existed from eternity? In the answer to this question there are several considerations requiring to be distinguished. First, science has no testimony to offer, inasmuch as it does not get beyond the area of laws now operating. Second, the testimony of science concerning the world as now existing is inconsistent with the supposition of its eternal existence. The matter which is constantly operated upon by energy distinct from itself, does not possess the property of self-subsistence; neither does the energy which is constantly undergoing change. Continual transition or change from one phase of existence, or set of relations, to another, is a mark of the not-abiding, an evidence of subjection to, and dependence on, what is beyond and above itself. The non-enduring, or ever-changing, is constantly pointing to the ever-enduring.

Full understanding of the situation of things as discovered by science will produce a much deeper impression on the public mind than has yet been effected. The reasonableness of this expectation will readily appear, if only some few of the positions be placed conspicuously in view.

It is of special consequence to note that science has in this direction _finished its work_, and reached its _ultimatum_, in demonstrating the physical impossibility of either increasing or diminishing the existing sum total of matter, or of energy. The conclusions are not such as can be regarded as provisional, liable to be overreached, modified, or enlarged, by what may afterwards be discovered. We are so much influenced at present,--and scientific men share in the experience, as well as others,--by the general and well-grounded expectation of the unceasing advance of science, that it is peculiarly easy in sight of a great general problem such as the origin and government of the world, to overlook the significance of ultimate conclusions in given directions. In this way, we too readily fall into the delusive tendency of regarding accredited conclusions as still hanging in a measure of uncertainty, or at least as having a dubious future before them, because they border upon the region of the unknown so far as science is concerned, or upon a realm of mystery, which science regards either with aversion, or with cherished determination of attack. In the present singularly favorable position of science, it is impossible for the public mind to escape this tendency; but it becomes only the more imperative to distinguish as occasion offers, those conclusions which are to be taken as final. This is of immense consequence as bearing upon general conceptions concerning the universe.

That matter can not be originated, and can not by even a single atom be destroyed, is one of those ultimate statements, upon which physical science itself relies as on a foundation. This is a universally accredited truth, that "no portion of matter, however small, goes out of existence or comes into existence in any operation whatever."[AK] The wonderful chemical laboratory of living organism may change many forms of matter into living tissue, but all returns again to its place in the inorganic mass. Material may pass from one phase into another, but there is nothing more than change. The sum total of material existence is unaltered. To suggest the contrary,--and specially to do so in the name of science,--were to bring science face to face with the conceptions rejected as alien to its very nature; for to say that matter may be originated, is to affirm _creation_; to say that it may be destroyed, is to affirm the possibility of _annihilation_; and these two are beyond the range of science, and if once admitted within its boundaries, they would destroy science itself.

So it is when we pass over to the doctrine of energy. The same clear and ultimate conclusion is proclaimed. The doctrine of the conservation of energy is the _ultimatum_ on which physical science finds sure and firm foothold. In those two ultimate positions of scientific research concerning inorganic existence, religion finds support, and that of a kind so powerful, that science itself depends upon its immovability.

There is, however, a further point connected with the doctrine of energy, which deserves consideration as bearing on the tendency to anticipate an indefinite line of progression in the history of this world, that is, deterioration or degradation in the form of energy, while it continues of equal amount. The efficient value of energy is according to the possibilities of transformation or transmutation. But its use implies limitation of the available forms, or steady deterioration of value. "Thus the energy of the universe is, on the whole, constantly passing from higher to lower forms, and therefore the possibility of transformation is becoming smaller and smaller, so that after the lapse of sufficient time all higher forms of energy must have passed from the physical universe, and we can imagine nothing as remaining, except those lower forms which are incapable, so far as we yet know, of any further transformation."[AL] Such a statement of the position, though it can not be regarded as an ultimate one in scientific research, is so obviously a deduction from present knowledge that it must to some extent modify prevailing conceptions. It may, indeed be suggested that some catastrophe may terminate the present order of things, and that some action of the law of gravitation may combine the fragments of worlds, and give a fresh start with new combinations of energy; but the bare suggestion of this implies a much wider range for scientific research than any thing yet known to us, and at the same time a larger demand upon intelligence in the control and regulation of what must nevertheless seem to us violent catastrophes. Such speculation, if it may warrantably find encouragement under purely scientific conditions, religious thought will neither gainsay nor resist; but will find itself in no perplexity to accept.

Waiving, however, all speculation as to the possible future of the physical universe, we here concentrate attention on the past; we take the most recent scientific testimony as to the structure of the physical universe, as it bears on the problem concerning the origin of our world. Here the testimony of science is clearly and unmistakably in favor of the creation or absolute origin of matter and energy, in the only form in which science can bear any testimony on the subject. It is, of course, impossible that science should present direct testimony to the fact of creation, as it is impossible that history should; for such a fact as creation must be entirely beyond the range of science. But in testifying to the indestructibility and uncreatability of matter under the conditions capable of being investigated by observational science; and in bearing the same testimony as to the energy in the world, it offers all the support it is capable of offering to the reality of the supernatural,--testifying to the dependence of nature on some power altogether transcending itself. But here I prefer rather to use the words of a purely scientific observer. When dealing with the doctrine of energy, and specially with the consequences of dissipation of energy, Professor Tait uses these words,--"As it alone is able to lead us, by sure steps of deductive reasoning, to the necessary future of the universe--necessary, that is, if physical laws remain forever unchanged--so it enables us distinctly to say that the present order of things has _not_ been evolved through infinite past time by the agency of laws now at work; but must have had a distinctive beginning, a state beyond which we are totally unable to penetrate; a state, in fact, which must have been produced by other than the now visibly acting causes."[AM] This is the utmost that science can say, bearing on the great problem of the origin of the universe; and nothing more powerful could be said in direct testimony to the reality of the supernatural, and the reasonableness of Christian faith, thus shown to be in complete harmony with science.