Of the various hypotheses which seek to dispense with the immediate agency of God, and to explain the conservation of the world by "secondary" or natural agencies, the second is that of active Force communicated to matter at its creation. This force being transformable, and at the same time indestructible, is regarded as adequate to the conservation of the universe.
This hypothesis must not be confounded with the Dynamical theory of matter propounded by Leibnitz, and more fully elaborated by Boscovich, which regards matter as a mere phenomenon or function of force; on the contrary, it conceives of matter as a distinct entity moving under the action of a primary impulse communicated by "the Creator's fiat at the beginning." This hypothesis in its fundamental conception and its further elaboration is purely mechanical. It represents the universe as a machine first set in motion by the Deity, and conserved by the actions and reactions of its several parts. All subsequent motions, changes, and configurations are the prolonged results of the original impulse, without any further direct action or control on the part of the Creator.
A more precise and accurate statement would require that the term "Energy" should be substituted for "Force." In the language of modern physics, Force is "that which originates or tends to originate motion or change," and "is wholly expended in the action it produces."[255] All energy has its origin in force, but force can not pass into energy except under conditions in which it is at liberty to act. For instance, the force of gravity produces the energy of motion of a falling body, but gravity can not produce motion unless there is space through which the body can fall. Energy, therefore, is defined as "the power of doing work."[256] The work done is the resistance overcome, and in overcoming resistance the energy is transformed, but not annihilated. In every case in which energy is lost by resistance, heat is generated; and we learn from Joule's investigations that the quantity of heat generated is a perfectly definite equivalent for the energy lost. It is therefore claimed that the total quantity of energy in the universe is constant, and that the material system is dynamically conservative. The universe is a self-acting and self-sustained machine, and perpetual motion is a necessary consequence.
A little reflection, however, ought to convince any one that this conception of the universe—as a machine which is kept in perpetual motion by the reciprocal action of its parts—is a false analogy. And its fallacy is apparent from this, that the moving force of every machine is not inherent in the machine, but some natural primary force distinct from the machine, such as gravity, or the primary atomic forces of attraction and repulsion; and consequently the very idea of mechanism assumes the existence of those primary forces of which it is the professed object of a mechanical theory of the universe to give an explanation. A machine "can no more create energy than it can create matter;" its sole function is "to transform energy into a kind most convenient for us."[257] "We may with the greatest ease convert mechanical work into heat, but we can not by any means convert all the energy of heat back again into mechanical work. In the steam-engine we do what can be done in this way, but it is a very small portion of the whole energy of the heat that is convertible into work, for a large portion is dissipated, and will continue to be dissipated however perfect our engine may become. Let the greatest care be taken in the construction and working of a steam-engine, yet we shall not succeed in converting one fourth of the whole energy of the heat of the coals into mechanical work."[258] It is impossible to construct a machine that can do work without parting with energy; and when the energy is all parted with, any machine whatever must necessarily cease to do any more work unless a fresh supply of energy be brought in from without. It is impossible to make a water-mill work without a constantly renewed supply of water, or to make a steam-engine work without a constantly renewed supply of fuel. "Every one who understands mechanics knows that any such inexhaustible supply of energy is impossible by means of merely mechanical arrangements; but it is equally true, though not perhaps equally so evident, that it is impossible by means of any arrangement of thermal, electric, or chemical forces."[259]
But we are told that modern science has proved that the law of the Conservation of Energy is an absolute law of the universe, and that though man can not construct a machine which will realize the dream of perpetual motion, the material universe is in reality such a machine. It becomes us to speak with some degree of diffidence in regard to a question which lies outside of our special department of study. Nevertheless we must confess that we have a growing suspicion of all so-called "absolute laws" in the domain of physical nature. And we are confirmed in this mistrust by the fact that physicists themselves are not agreed in regarding this law of conservation of energy as universally true. "That the amount of energy in the world is unchangeable, the sum of the actual or kinetic and potential energies being a constant quantity, has been by some writers overstrained. It may be taken as a postulate, and is probably true, but it is a proposition equally incapable of proof and of disproof."[260] "This principle," says Sir J. Herschel, "so far as it rests upon any scientific basis as a legitimate conclusion from dynamical laws, is no other than the well-known dynamical theorem of the conservation of vis viva (or of 'energy,' as some prefer to call it), supplemented to save the truth of its verbal enunciation by the introduction of what is called 'potential energy,' a phrase which I can not help regarding as unfortunate, inasmuch as it goes to substitute a truism for the announcement of a dynamical fact. No such conservation, in the sense of an identity of total amount of vis viva at all times and in all circumstances, in fact, exists. So far as a system is maintained by the mutual actions and reactions of its constituent elements at a distance (i. e., by force), vis viva may temporarily disappear, and be subsequently reproduced between certain limits. Collision, indeed, between its ultimate particles or atoms, regarded as absolutely rigid, and therefore inelastic (for that which can not change its figure can have no resilience), can not take place without producing a permanent destruction of it, which there exists no means of repairing.... If, indeed, we could be assured à priori that the system [of the universe] is one of simple or compound periodicity, in which a certain lapse of time will restore every molecule to identically the same relative situation with respect to all the rest, we should then be sure that in the nature of things there would take place, so to speak, a winding up from a lower to a higher state of potential energy, to be subsequently exchanged for newly created vis viva. But, as we can have no such à priori assurance, can only assume such restoration to be possible, and can see no means of effecting it, if possible, otherwise than by foresight and prearrangement; the one equally with the other is an unknown function, variable within unknown limits, and susceptible of fluctuation to an unknown extent; nor can we have any, the smallest, right to assert that what is expended in one form is necessarily laid up for further use in the other. It would be very difficult, I apprehend, to show whether, in the winding up of a clock or the building of a pyramid, taking into consideration all the various modes in which vis viva disappears and reappears in the expenditure of muscular power, the evolution of animal heat, the consumption of the materials of our tissues, the propagation of vibratory motions, and a thousand other modes of transfer, the total vis viva of this our planet is increased or diminished. That it should remain absolutely unchanged during the process is in the last degree inconceivable. The amount of vis viva latent in the form of heat or molecular motion in the sun and planets in our immediate system may bear, and probably does bear, a by no means inappreciable ratio to that more distinctly patent in the form of bodily motion in the periodic circulation of the planets round the sun, and the sun and planets round their axes. The latter amount fluctuates to and fro according to laws easily calculable, but the former we have no means whatever of computing, and to what extent, or within what limits, it may be variable, we are altogether ignorant."[261]
The two dynamical laws of Conservation of Energy and Transformation of Energy can not therefore be regarded as universal and absolute laws; they are particular and derivative laws subject to limitations which are supplied by the third dynamical law—the Dissipation of Energy. The law of the conservation of energy simply asserts "that the whole amount of energy in the universe, or in any limited system which does not receive energy from without, or part with it to external matter, is invariable;" in other words, that every material system subject to no other forces than actions and reactions between its parts is a dynamically conservative system. But Sir William Thomson has shown that "in nature this hypothetical condition is apparently violated in all circumstances of motion. A material system can never be brought through any returning cycle of motion without spending more work against the mutual forces of its parts than is gained from these forces, because no relative motion can take place without meeting with frictional or other forms of resistance."[262] "There can be but one ultimate result for such a system as that of the sun and planets, if continuing long enough under existing laws, and not disturbed by meeting with other moving masses in space. That result is the falling together of all into one mass, which, although rotating for a time, must in the end come to rest relatively to the surrounding medium."[263]
The law of the transformation of energy is "the enunciation of the empirical fact that in general any one form of energy may by suitable processes be transformed, wholly or in part, to an equivalent amount in any other given form." This law, however, is subject to limitations which are supplied by the dissipation of energy. "No known natural process is exactly reversible, and whenever an attempt is made to transform and retransform energy by an imperfect process, part of the energy is necessarily transformed into heat and dissipated, so as to be incapable of further useful transformation. It therefore follows that, as energy is constantly in a state of transformation, there is a constant degradation of energy to the final unavailable form of uniformly diffused heat, and that will go on until the whole energy of the universe has taken this final form."[264] No mechanical work can be done by heat in a state of equilibrium; as a dynamical agent it is dead. "Thus the inexorable laws of mechanics indicate that the store of force in our planetary system, which can only suffer loss and not gain, must be finally exhausted."[265]
So far, then, as the conservation of energy has any scientific meaning, it is inadequate to account for the origin or explain the continuance of the existing order of nature. It is true we may conceive that every atom of matter was endowed at the Creation with a certain store of potential energy—"the potential energy of gravitation"[266]—which it has ever since given out; but as every motion which has resulted from its action has been attended with the expenditure of a certain amount of the original endowment, it must have been continually undergoing a diminution. There is, says Professor Norton, no escaping this conclusion but by taking the ground that the primary atomic forces (as gravitation, and the atomic repulsion and attraction by which atoms are aggregated into bodies of sensible magnitude) are correlated with the living forces (or various forms of energy) which are involved in the motions that have resulted from the previous operation of the primary atomic forces. "But," he says, "no evidence has been obtained of any such correlation." The primary force of attraction (if it be regarded as a primary force) may be the cause of motion in bodies which are separated in space, and part of that energy of motion may be transformed into the energy of heat or light or electricity, but the primary force of attraction is not transformed. Energy is convertible into other forms of energy, but heat, light, and electricity are not transformable into primary force. The correlation of force and energy is therefore a scientific heresy.[267]
Modern physicists are agreed that visible motion, heat, electricity, magnetism, and radiance (radiant light and heat) are forms of actual energy which are correlated and capable of mutual conversion. Any one form may, by suitable processes, be transformed, wholly or in part, to an equivalent amount of any other form of energy. So much is generally accepted by scientific men.
But in regard to the primary force or forces in which these forms of energy have their origin, there is not the same agreement among physicists. Some regard gravitation, cohesion, and chemical affinity as the three primary forces of nature; while others suggest that the last two are related with and probably derived from the first.
There is also a respectable school of physicists who teach that atomic attractions and repulsions are the universal cosmic forces which originate all molecular and mechanical motions. Then, again, each of these forms of force have their special advocates. On the one side it is affirmed, as an important generalization, that all primary force is attractive; "there is no such thing in nature as a primary repulsive force."[268] Universal attraction is the one world-forming and world-conserving energy. On the other side it is contended that gravitation is not a primary, but a secondary and derivative force, and that the grand primal force is a universal force of repulsion.[269]
It is beyond our province to discuss the merits of these conflicting theories. Our position is that no purely physical hypothesis is adequate to account for the conservation of the universe, and therefore it is of little consequence to our argument which of the above theories may find most favor with scientific men. The tendency of modern scientific thought is toward the conception of "one primordial form of matter, and but one primary form of force," as the simplest basis upon which a physical theory of inanimate nature can be erected. The ultimate nature of this one primary force is a question for pure metaphysics. From the stand-point of physical science it can only be thought "as a pull or a push in a straight line."[270] Universal attraction or universal repulsion must be the ultimate dynamical conception for the pure physicist.
1. Let us consider the first hypothesis. It is claimed that gravitation, or universal attraction, is the great conserving and sustaining principle of the universe. A stone falls to the earth, a round body rolls along a plane inclined toward the horizon; a liquid mass, as a brook or a large river, flows on the sloping surface which forms its bed. All these phenomena are the varied manifestation of a universal tendency in all bodies to fall one toward the other. In virtue of this tendency the great orbs which hang suspended in space gravitate toward one another; the moon and the earth fall toward each other, and they both gravitate toward the sun. All the planets of our solar system continually act one on the other, and on the immense sphere which shines at their common focus. By its enormous mass, the sun keeps all of them in their orbits. If we ask why one body falls toward another which is more than ninety millions of miles off, in preference to moving in any other direction, the answer given is that, "Every particle of matter in the universe attracts every other particle with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distance from each other." This force of attraction is the universal bond which holds the universe together, and sustains its physical life.
To the superficial thinker, the language of the Newtonian philosophy appears to sanction the materialistic notion that gravitation and attraction are active powers essential to and inherent in matter. Such, however, was by no means the doctrine of Newton, and he was careful to guard his readers against any such misapprehension of his meaning. "The words attraction, repulsion, or tendencies of whatever kind toward a centre, I use indifferently and without distinction for each other, considering these forces not physically but metaphysically. Wherefore let not the reader suppose that by words of this kind I any where mean a species or mode of action, or cause, or physical reason; or that I really and in a physical sense assign forces to centres (which are only mathematical points), even though I may say that centres attract, or that forces belong to centres."[271]
The history of scientific opinion on the point before us furnishes a striking illustration of the manner in which language reacts on the ideas which it is intended to express, and thus men fall into the habit of talking nonsense without knowing it. The conception of atoms having the property of exerting various forces across a void space seemed to follow as a matter of course from the discovery of the law of gravitation, and from the language in which it is expressed. After Newton a school arose which taught that atoms have the property of exerting force at a distance, and that this property must be inherent in the atoms, just as Lucretius taught that hardness and elasticity were original indefeasible properties of the primordial elements, the "semina rerum," or seeds of things. But Newton did not teach this; he stated a fact, but did not devise an hypothesis; he attempted no explanation of the law of gravitation.
"The law of gravitation considered as a result is beautifully simple; in a few words it expresses a fact from which most numerous and complex results may be deduced by mere reasoning—results found invariably to agree with the records of observation; but this same law of gravitation looked upon as an axiom or first principle is so astonishingly far removed from all ordinary experience as to be almost incredible. What! every particle in the whole universe is actively attracting every other particle [that is, every particle in the universe with the same force, without any expenditure of force], through void, without the aid of any communication by means of matter, or otherwise—each particle, unchecked by distance, unimpeded by obstacles, throws this miraculous influence to infinite distance without the employment of any means![272] No particle interferes with its neighbor, but all these wonderful influences are co-existent in every point in space! The result is apparent at each particle, but the condition of intermediate space is exactly the same as though no such influence were being transmitted across it! Earth attracts Sirius across space, and yet the space between is as if neither Earth nor Sirius existed! Can these things be? We think not; and Newton himself did not affirm this."[273] On the contrary, he earnestly rejects any such hypothesis. "It is inconceivable that inanimate brute matter should, without the mediation of something else which is not material, operate upon and affect other matter without mutual contact, as it must do if gravitation, in the sense of Epicurus, be essential to and inherent in matter.... That gravitation should be innate, inherent, and essential to matter, so that one body may act upon another at a distance, through a vacuum, without the mediation of any thing else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting constantly according to certain laws."[274]
The ancient axiom that "Matter can not act where it is not any more than when it is not," was universally believed till Newton's time, and Newton himself regarded it as a self-evident truth. Some of his disciples asserted that gravitation must be considered as an essential property of matter, and they were under the necessity of assuming that atoms can exert a force upon one another across a void. This to Leibnitz was either miraculous or absurd; and in modern times the doctrine is rejected by the first physicists—by Faraday, Helmholtz, Thomson, Tait, and Maxwell.[275] Sir William Thomson, the Newton of modern physics, says emphatically, "I have no faith whatever in attractions and repulsions acting at a distance between centres of force according to various laws."[276] And Clerk Maxwell, in his lecture on "Action at a Distance,"[277] explains how Faraday, by his discovery of magnetic rotation of polarized light, and by his showing how lines of force arise in media, "rudely shook the theory of attraction and repulsion at a distance across a void."
If, now, "direct action at a distance" is rejected by scientific men as inconceivable and absurd, how can it be that the sun pulls the earth toward it, and holds the planets in their orbits? The verbal statement of the law of gravitation is no answer to this question. It expresses a fact, but it does not assign a cause. Gravitation is a phenomenon which demands an explanation, and some of the first scientists of the day are engaged in devising a theory which shall afford a rational answer to the question, What is the cause of gravity?[278]
The first and most fundamental presupposition for any physical hypothesis which seeks to explain the action of gravitation is that some medium of communication exists. This is suggested by every physical analogy. Sound is communicated through a medium. The influence which is exerted at a distance by heat, light, electricity, and magnetism is effected through media. The most plausible suggestion yet made is that "a single omnipresent fluid, ether, fills the universe," which by various forms or modes of motion transmits light, radiant heat, magnetism, and electricity.[279] May not gravitation, it is asked, be transmitted by the same fluid? may it not consist of or result from actual recurring impulses propagated in ethereal waves?
The hypothesis that gravitation is transmitted through the same medium as light, or indeed through any medium, is encumbered with serious if not insuperable difficulties. All transmission of whatever kind—of a letter by the post, a gunshot, a sound, a wave of light, an electro-magnetic disturbance—occupies time. It has a velocity—sometimes a very great one, as in the case of light; still it is a measurable velocity. But, according to Herschel, the pull which the sun exerts on the earth is delivered instantaneously. Were it not so there would be "a continually progressive increase of the major axis of the earth's orbit, and therefore of the length of the year."[280] Surely it must be obvious to every one that the instantaneous transmission of the sun's attractive force to the planet Neptune, three thousand millions of miles distant, through a physical medium like the ether, would be as great a miracle as action at a distance through a perfect void. But the advocates of this hypothesis have not thereby escaped the difficulties of action at a distance. The majority of physicists regard the luminiferous ether as consisting of "discrete particles"—"elementary molecules of inconceivable minuteness and tenuity." These ultimate particles or atoms of highly attenuated matter must have some magnitude, some extension, however inconceivably minute. If extended, they must have some form, and must occupy separate positions in space. If they are capable of motions—undulatory, rotatory, or spiral motions—they can not be in mutual contact. Conceive, then, two such atoms, and draw around each an imaginary circle. Let these circles touch at the middle point between the two, and ask yourself the question, What exists there? On the hypothesis under consideration you are bound to answer pure, empty space—that is, pure nothing. "But if there is no matter between the atoms, then all their actions, one upon the other, must be exerted across a void—that is, through a medium of nothingness;" in other words, through no medium at all. Now the size of the interval makes no difference in the argument. "Whether that interval be the 92 billionth of an inch, or the 92 millions of miles or thereabouts between the earth and the sun, it is still action at a distance, and no escape."[281]
The physicist who regards the ether as consisting of discrete particles not in bodily or actual contact, and at the same time finds himself logically compelled to reject this "mystical action at a distance," has no alternative but to accept the doctrine of Newton that the action of one particle of matter upon another is mediated by an agent which is not material. "If it be true that the conception of force as the originator of motion in matter without bodily contact ... is essential to the right interpretation of phenomena; and if it be equally true, on the other hand, that its exertion makes itself manifest to our personal consciousness by that peculiar sensation of effort which is not without its analogue in purely intellectual acts of the mind, it [i. e., force] comes not unnaturally to be regarded as affording a point of contact, a connecting link between these two great departments of being—between mind and matter—the one as the originator, the other as the recipient of force."[282]
There are distinguished physicists—as Helmholtz, Thomson, Challis, and Maxwell—who seek to escape the difficulties of action at a distance by the assumption that the ether is absolutely continuous (and therefore does not consist of atoms)—a perfectly homogeneous, incompressible, frictionless fluid which fills the universe. This fundamental presupposition as the basis of a physical theory of the universe necessitates the further assumption that "motion is the very essence of what has been hitherto called matter."[283] All quantitative and qualitative phenomena, all statical and dynamical phenomena, are due solely to varied modes of motion in the primordial fluid. "By various motions of the nature of eddies [ring-vortices], the qualities of matter—cohesion, elasticity, hardness, weight, mass, or other universal properties of matter—are given to small portions of the fluid which constitute the chemical atom, and these, by modifications in their combinations, form, and motion, produce the accidental phenomena of gross matter.... On this view, gross matter would be merely an assemblage of parts of the medium moving in a peculiar way, groups of ring-vortices having inertia.... The primary fluid by other motions transmits light, radiant heat, magnetism, and gravitation."[284]
It may be regarded as an act of presumption in an obscure critic to offer an opinion of the theories of these great masters in science. We venture, however, to suggest that most men will find a difficulty in conceiving how space absolutely full of matter can be made to contain more, or how a truly continuous substance can be capable of condensation. The most tenuous ether, if it be absolutely continuous, occupies the whole of the space in which it lies—that is, there is no point of the space which is not occupied by a point of matter.[285] But the hardest iron can do no more than this, and, therefore, on this hypothesis it seems impossible to account for its greater density. It is suggested that if molecules are mere assemblages of parts of the ether moving in a peculiar way, then greater density may be due to a modification in the motion of molecules, and not merely to the greater frequency of the eddying molecules in a given space. But how can a truly continuous substance have parts, and how can relative motion occur in an absolute plenum? The very notion of particles is quite inconsistent with the continuity of matter; and in a universe absolutely full no motion whatever would be possible. We are told that Sir William Thomson and Professor Tait find no difficulty in all these, to our minds, contradictory conceptions, and therefore we must conclude that our intellect is not properly "focussed so as to give definition without prenumbral haze."
Granting, then, the absolute continuity of all matter, and the possibility of motion in an absolute plenum, the question which concerns us most in this essay is, How is motion generated and sustained? One of the greatest lights of this new school tells us that "all we can affirm of matter is that it is the recipient of impulse and of energy."[286] They no longer regard the atom "as a mystic point endowed with inertia and the attribute of attracting and repelling other such centres with forces depending on the intervening distances."[287] They have "no faith whatever in attractions and repulsions acting at a distance between centres of force."[288] Force, then, is not regarded by these leading physicists as an inherent attribute of matter. The primary fluid, originally inert and motionless, must have been set in motion by some force, by some agency external to and distinct from itself. An "original impetus" from without, according to Maxwell,[289] or a "pressure" of the universal ether "from somewhere outside the world of stars," according to Challis,[290] must be the source of all motion and all forms of energy in the universe.
It is a fundamental principle of dynamics that "force is wholly expended in the action it produces,"[291] therefore, if all the forms of energy in the universe are the result of pressure, that pressure must be continuous; if they are the result of impulses, these impulses must be incessantly renewed, and must recur with immeasurable rapidity. On either supposition, "the universe is not even temporarily automatic, but must be fed from moment to moment by an agency external to itself," and "the preservation of the universe is effected only by the unceasing expenditure of enormous quantities of work;"[292] that is, it is ceaselessly sustained by Divine Omnipotence—"He upholdeth all things by the word of his power."
So much with respect to the first form of this hypothesis which regards atomic attraction as the sole world-forming and world-conserving force. We turn now to that form of the hypothesis which considers atomic repulsion as the grand primal force in which all the other physical forces, even gravitation itself, have their origin.
This view is presented by Professor W. A. Norton, in his articles "On Cosmical and Molecular Physics" in the American Journal of Science and Arts. His theory rests essentially upon the following principles:
1. The doctrine of inertia applied to all matter.
2. The existence of a single primary force of repulsion exerted by every atom upon every other atom.
3. The existence of but one primary form of elementary matter, viz., the universal or luminiferous ether; the atoms, so called, of ordinary matter, and of the electric ether being but different masses of condensed luminiferous ether.
4. The doctrine of the interception of force by matter. This is a necessary consequence of the fact that a certain portion of the propagated force is instantly expended in imparting motion to the molecules or atoms which it encounters, and is therefore abstracted from this force.
5. The primary force of repulsion is made up of impulses recurring with an immeasurable rapidity. This is no new hypothesis. In all treatises on Mechanics, gravity and all incessant forces are conceived to consist of an indefinitely great number of impulses taking effect in a finite interval of time.[293] "The ever-recurring pulses of the primary cosmical force, emanating from all the atoms of the one primary form of matter, are directly consumed in communicating opposite movements, or virtual movements, to every atom in the universe. It is, as I conceive, because in the existing condition of things the distribution of matter is unequal in different directions round a point, and therefore the partial interception of the impulses of the cosmical force along the different lines of direction is unequal, that an effective gravitating force exists.[294] The entire amount of the cosmical force consumed in any interval of time is the amount intercepted by all the atoms of matter, and is independent of the motions that result from the inequalities just noticed. Gravitation, and molecular and chemical attractions, which originate in the gravitation of electric ether toward atoms of ordinary matter, are then derivative forces incidental to the direct actions exerted by the cosmical force upon the atoms."[295]
In a communication from Professor Norton to the author, he furnishes the following further exposition of his theory: "If, as I conceive, the primary atomic force is of the nature of a perpetual emanation from each atom, and is expended in the act of producing motion, we must thence infer that the atom is an entity through which a stream of force is perpetually flowing from the Infinite Source of all power and all existence. That the primary force is a force of repulsion, and that the immediate source of all the forces that are known to take effect upon ordinary matter is the action of recurring repulsive impulses upon the atoms of the universal ether, and their subsequent propagation and partial interception by the atoms which they encounter, I infer from the fact that this conception furnishes a rational explanation of all the known forces and phenomena of inanimate nature."
It will thus be seen that the theory of Professor Norton gives no countenance to the materialistic tendencies of the physical science of the age. He is decidedly of the opinion that "force is not an inherent and essential attribute of matter," and he "devoutly acknowledges that in following the chain of cause and effect into the precincts of that most deeply hidden of all mysteries, the origin of force, we have come into the presence of the Infinite Spirit who puts forth unceasingly, from every point in the realms of space, his creative and sustaining power upon the subtile matter that fills all space, and is the essential substance of all worlds."[296]
3. The third hypothesis is that of a plastic nature, intermediate between God and the material universe, by which all the phenomena of visible nature are produced.
This hypothesis was first presented (at least in modern times) by Ralph Cudworth, in his "True Intellectual System of the Universe."[297] In opposition to Democritus, who explained all phenomena by means of matter and motion; and also in opposition to Strato, who taught that matter is the only substance, but at the same time a living and active force, Cudworth maintains that there is a plastic nature—a vital and spiritual, but unconscious energy, distinct from and created by the Deity, which "doth drudgingly execute that part of his providence which consisteth in the regular and orderly motion of matter,"[298] and in the organization and development of plants and animals, "according to laws prescribed for it by a perfect intellect, and impressed upon it."[299] This plastic nature is an "inferior kind of life or soul," destitute of all consciousness,[300] which, though it "acts for the sake of ends," does "not know the reason of what it does," and therefore operates "fatally and sympathetically."[301]
The arguments urged by Cudworth in support of this hypothesis are mainly of a negative character. On the one hand he endeavors to show that force and vitality are not essential attributes of matter, and on the other hand that the motion and life of the universe can not be properly regarded as the direct action of the Deity upon matter. It is with this latter part of the argument that we are here immediately concerned. He urges (1) that if every thing in nature were done immediately by God, it would render Divine Providence "oporose, solicitous, and distractious;" and, furthermore, it would be unbecoming the Divine Majesty, and "indecorous," for God "immediately to do all the meanest and triflingest things Himself drudgingly." He maintains (2) that if God do all things immediately, then he does them "miraculously"—that is, "forcibly and violently." And (3) that the immediate agency of God is inconsistent with that slow and gradual development of things we see in nature, which would seem to be a "trifling formality" if the agent were omnipotent, and especially inconsistent with "those errors and bunglings which are committed when the matter is inept and contumacious." "Wherefore it may be concluded that there is a plastic nature under God which, as an inferior agent, doth drudgingly execute that part of his providence which consists in the regular and orderly motion of matter, yet so that there is also a higher providence, which, presiding over it, doth often supply the defects of it, and sometimes overrule it; forasmuch as the plastic nature can not act electively nor with discretion." So that, after all, as Plato says, God "is the beginning and end and middle of all things," and therefore their being is "as much to be ascribed to his causality as if Himself had done all things immediately without the concurrent instrumentality of any subordinate natural cause."[302]
There is nothing original in this hypothesis of a plastic nature except perhaps the name. It is the old anima mundi of the Platonic physics, a vital soul of the world, distinct from but created by the Supreme God. It has reappeared under various names in the history of natural science, especially in that department which is now comprehended under the general name of Biology. The "motus tonico-vitalis" of Stahl, the "animating principle" of Harvey, the "materia vitæ" of John Hunter, the "organic force" of Müller, and the "organic agent" of Dr. Prout, are all but separate names "for an imaginary principle, or entity, possessing powers and properties which (however men may try to impress themselves with a contrary notion) would entitle it to rank as an intelligent agent. It is true that, according to most of the advocates of this doctrine, this power is supposed to be superintended and controlled by the Deity himself, and by this supposition they have screened themselves against the accusation of attributing to a creature the powers of the Creator."[303]
Cudworth's hypothesis of a plastic nature has been recently reproduced, without the slightest recognition of its paternity, by Joseph John Murphy, under the name of "unconscious intelligence"—"a power transcending the ordinary properties of matter and adapting means to purposes, presiding over all vital actions, whether formative, motor, or mental, directing each action to its specific end."[304] Mr. Murphy is very solicitous that we should not understand him to teach that "the formative intelligence" which in nature adapts structure to function is Divine. "I believe," he says, "that the Creator has not separately organized every structure, but has endowed vitalized matter with intelligence, under the guidance of which it organizes itself."[305] This "unconscious intelligence," which builds the tissues and fashions the organs of plants and animals, becomes conscious of itself in the deliberate thought of man.[306]
It is worthy of note that this hypothesis commends itself to the mind of Murphy by considerations akin to those which are urged by Cudworth; and especially because it is supposed to relieve certain moral difficulties connected with the belief of a Divine purpose in creation—as, for example, the existence of parasitic worms which inflict pain and disease on beings endowed with sensation and consciousness, and the presence of "immoral instincts" in higher forms of animal life.[307]
We readily grant that the relation of God to the existing order and economy of the world is mysterious; and we believe that no conceivable hypothesis can deprive it of this mysteriousness. There are numerous difficulties which arise from the imperfection of our knowledge and the limited range of our powers. We see through an obscure medium, and we know only in part. There are also difficulties peculiar to individual minds—intellectual, ethical, emotional difficulties—which are the products of a peculiar culture, or the offspring of certain theoretical prepossessions. Some of these difficulties may be relieved by the hypothesis of "unconscious intelligence," but on a further examination it will be found that this hypothesis is embarrassed with still greater difficulties and open to more serious objections both intellectual and moral.
First, there is the difficulty of forming any conception of "unconscious intelligence." This has been felt by the ablest minds. "The hypothesis," says Wallace, "has the double disadvantage of being both unintelligible and incapable of any kind of proof."[308] Mivart observes that the phrase will "to many minds appear to be little less than a contradiction in terms; the very first condition of an intelligence being that, if it know any thing, it should at least know its own existence."[309] Mr. Murphy tells us that this unconscious intelligence "adapts means to ends," "it presides over all vital actions, directing each action to its specific end."[310] But an intelligence adapting means to ends without any knowledge (consciousness) of either the ends to be secured or the means to be employed to secure the end surpasses all comprehension and all belief. We can readily believe, with Hamilton, that the human mind "exerts energies and is the subject of modifications" of which it is not immediately conscious, the combined results of which are manifested in the complex fact of consciousness. But to call that intelligence which never had a perception, a thought, an emotion; which has no knowledge of self or of any thing else; in short, which is not and never was conscious, is to reduce philosophic terminology to chaos, and tantalize thought by meaningless words. An intelligent agent is one who understands, who distinguishes between subject and object, who knows things in their relations, who can unite the terms of a relation in thought, and judge of their congruity or incongruity, all of which are conscious operations. Intelligence is consciousness (conscientia = relational knowledge); unconscious intelligence is unconscious consciousness, unintelligent intelligence, which is a contradiction and an absurdity.
Secondly, in endeavoring to find the mental stand-point of Mr. Murphy, in order that we may fairly estimate his hypothesis, we encounter the still more serious difficulty of conceiving how unconscious intelligence can exist apart from some subject or substratum in which it inheres.
We are aware that "the tendency of modern thought" is to hypostatize force and intelligence, and conceive them as entities. We have conscientiously made the attempt again and again to realize this conception, but we must confess we can only conceive of force and intelligence as properties or attributes of some subject. It is beyond our ability, and we imagine it is beyond the ability of Mr. Murphy, to conceive of force without something that exerts force, of intelligence without a being who is intelligent. Indeed, Mr. Murphy concedes that "where there are properties there must be a substance,"[311] and by substance, he says, he understands "underlying reality."[312] Unconscious intelligence, if there be such a thing, must be an attribute or quality inherent in some underlying substance. But Mr. Murphy asserts "there is no scientific basis for the old belief in a distinct mental substance"[313]—that is, if we understand him aright, so far as finite mind is concerned. On the other hand, he distinctly affirms that this unconscious intelligence is not Divine intelligence. The power and intelligence which work in the world of matter and mind "are not the Divine power and intelligence."[314] Unconscious intelligence, then, must be an "endowment of vitalized matter;"[315] and "life has its origin in no secondary cause, but in the direct action of creative power."[316] Now the question arises, What is matter? On this point we must be careful not to misunderstand or misrepresent Mr. Murphy. "Matter, whether viewed from a metaphysical or from an inductive point of view, is known only as a function of force, and can be described only in terms of force. In other words, the universe is nothing but a manifestation of force." And now we ask, Of what force? "Force," says Mr. Murphy, "is known to us by immediate consciousness as a function of our own mind and will; that is to say, the mind, acting in will, is conscious of itself as a force—and we are able to conceive of force in no other way; the only conception of force which we are able to frame is that of voluntary force, or the exertion of will. Either the force manifested in the universe is the force of a Creative Will, or we are able to form no conception of it whatever."[317] Can there be any possibility of misunderstanding this language? Matter itself is not an entity, not a substance; it is a phenomenon, not a reality. Matter is "a function of force." Force is a "fact of mind, and therefore spiritual." Consequently "matter can only be conceived as spiritual."[318] And now let us recall the statement of Mr. Murphy that there is no finite, created, underlying reality for the phenomena of mind and will—"no distinct mental substance." If we hold to this doctrine, then we must say with Mr. Murphy again that "the powers of matter and mind alike are the result and expression of a Living Will—and if a Living Will, then also an Intelligent Will."[319] The final and only conclusion is that God, "the Self-existent Being," is the one only underlying reality or substance in the universe; all the force in the universe is "the force of the Creative Will," and all the intelligence in the universe a modification of the Divine Thought.
This, however, is Pantheism, even according to that very defective definition of Pantheism given by Mr. Murphy: "Pantheism is the identification of the Divine power and intelligence with the powers and intelligences that work in the world of matter and mind."[320] Still, Mr. Murphy declares, "I am not a Pantheist;" and we are bound to accept his disclaimer—"the power and intelligence which work in nature are not identical with the Divine power and intelligence." Be it so; then there is power, and there is intelligence in nature, which are not attributes of any reality, and which do not inhere in any substance; and we come round to the original difficulty of conceiving of an attribute apart from a subject.
The reader can not have failed to see that Mr. Murphy has been leading us round a vicious circle. "Force is a function of matter, and matter is a function of force."[321] "Matter is only explicable as a function of force, force only explicable as a function of conscious mind,"[322] and mind is "one of the functions of matter."[323] "It is perfectly certain," says Mr. Murphy, "that inductive psychology gives no hint of any mental substance as distinguished from the material substance of the brain."[324] But the material substance of the brain after all is not material; "matter can only be conceived as spiritual"[325]—that is, as force. There is no underlying reality which men call "matter," and there is no underlying reality which men call "spirit." Matter is spirit, spirit is matter; but in reality neither the one nor the other has any substantial reality. If all finite existences are but modes of the Infinite Being, we have a consistent Pantheism at any rate. But if all finite existences are simply phenomena without any underlying reality, then "perception is a dream, and my existence the dream of that dream."
Thirdly, the hypothesis of an "unconscious intelligence," distinct from the Supreme Intelligence, which does "the drudgery of Providence," and to which the defects and disorders and "immoralities" of nature are ascribed, is neither adequate nor satisfactory.
The conceit of Cudworth that it is unbecoming the Divine Majesty to be immediately concerned in every thing that takes place in nature is scarcely worthy of consideration: "If it were not congruous in respect of the state and majesty of Xerxes, the king of Persia, that he should condescend to do all the meanest offices himself, much less can this be thought decorous in respect of God."[326]
Human conceptions of what is great or small, dignified or indecorous, are merely relative conceptions which vary with our knowledge, culture, and taste; but—