INTRODUCTION
When Descartes, in the first half of the seventeenth century, said that there are only two kinds of things or substances in nature, namely, extended substances and thinking substances, or bodies and spirits; that, in bodies, everything is reducible to extension with its modifications of form, divisibility, rest and motion, while in the soul everything is reducible to thinking with its various modes of pleasure, pain, affirmation, reasoning, will, etc.... ; when he in fact reduced all nature to a vast mechanism, outside of which there is nothing but the soul which manifests to itself its existence and its independence through the consciousness of its thinking, he brought about the most important revolution in modern philosophy. To understand its significance however, an account must be given of the philosophical standpoint of the time.
In all the schools at that time the dominant theory was that of the Peripatetics, altered by time and misunderstood, the theory of substantial forms. It posited in each kind of substance a special entity which constituted the reality and the specific difference of that substance independently of the relation of its parts. For example, according to a Peripatetic of the time, “fire differs from water not only through the position of its parts but through an entity which belongs to it quite distinct from the materials. When a body changes its condition, there is no change in the parts, but one form is supplanted by another.”1 Thus, when water becomes ice, the Peripatetics claimed that a new form substituted itself in place of the preceding form to constitute a new body. Not only did they admit primary or basal entities, or substantial forms to explain the differences in substances, but for small changes also, and for all the sensible qualities they had what were called accidental forms: thus hardness, heat, light were beings quite different from the bodies in which they were found.
To avoid the difficulties inherent in this theory, the Schoolmen were led to adopt infinite divisions among the substantial forms. In this way the Jesuits of Coïmbre admitted three kinds of these forms: first, the being which does not receive its existence from a superior being and is not received into an inferior subject,—this being is God; second, the forces which receive their being from elsewhere without being themselves received into matter,—these are the forms which are entirely free from any corporeal concretion; third, the forms dependent in every respect, which obtain their being from a superior cause and are received into a subject,—these are the accidents and the substantial forms which determine matter.
Other Schoolmen adopted divisions still more minute and distinguished six classes of substantial forms, as follows: first, the forms of primary matter or of the elements; second, those of inferior compounds, like stones; third, those of higher compounds, like drugs; fourth, those of living beings, like plants; fifth, those of sensible beings, like animals; sixth, above all the rest, the reasoning (rationalis) substantial form which is like the others in so far as it is the form of a body but which does not derive from the body its special function of thinking.
Some have thought, perhaps, that Molière, Nicole, Malebranche and all those who in the seventeenth century ridiculed the substantial forms, calumniated the Peripatetic Schoolmen and gratuitously imputed absurdities to them. But they should read the following explanation, given by Toletus, of the production of fire: “The substantial form of fire,” says Toletus, “is an active principle by which fire with heat for an instrument produces fire.” Is not this explanation even more absurd than the virtus dormitiva? The author goes on to raise an objection, that fire does not always come from fire. To explain this he proceeds, “I reply that there is the greatest difference between the accidental and the substantial forms. The accidental forms have not only a repugnance but a definite repugnance, as between white and black, while between substantial forms there is a certain repugnance but it is not definite, because the substantial form repels equally all things. Therefore it follows that white which is an accidental form results only from white and not from black, while fire can result from all the substantial forms capable of producing it in air, in water or in any other thing.”
The theory of substantial or accidental forms did more than to lead to nonsense like the above; it introduced errors which stood in the way of any clear investigation of real causes. For example, since some bodies fell toward the earth while others rose in the air, it was said that gravity was the substantial form of the former and lightness of the latter. Thus heavy and light bodies were distinguished as two classes of bodies having properties essentially different, and they were kept from the inquiry whether these apparently different phenomena did not have an identical cause and could not be explained by the same law. It was thus again that seeing water rise in an empty tube, instead of inquiring under what more general fact this phenomena could be subserved, they imagined a virtue, an occult quality, a hatred on the part of the vacuum, and this not only concealed the ignorance under a word void of sense but it made science impossible because a metaphor was taken for an explanation.
So great had become the abuse of the substantial forms, the occult qualities, the sympathetic virtues, etc., that it was a true deliverance when Gassendi on the one hand and Descartes on the other founded a new physics on the principle that there is nothing in the body which is not contained in the mere conception of bodies, namely extension. According to these new philosophers all the phenomena of bodies are only modifications of extension and should be explained by the properties inherent in extension, namely, form, position, and motion. Upon this principle nothing happens in bodies of which the understanding is not able to form a clear and distinct idea. Modern physics seems to have partially confirmed this theory, when it explains sound and light by movements (vibrations, undulations, oscillations, etc.), either of air or of ether.
It has often been said that the march of modern science has been in the opposite direction from the Cartesian philosophy, in that the latter conceives of matter as a dead and inert substance while the former represents it as animated by forces, activities and energies of every kind. This it seems to me is to confuse two wholly different points of view, that is the physical and the metaphysical points of view. The fact seems to be that from the physical point of view, science has rather followed the line of Descartes, reducing the number of occult qualities and as far as possible explaining all the phenomena in terms of motion. In this way all the problems tend to become problems of mechanics; change of position, change of form, change of motion—these are the principles to which our physicists and our chemists have recourse whenever they can.
It is therefore wrong to say that the Cartesian line of thought has completely failed and that modern science has been moving away from it more and more. On the contrary we are witnessing the daily extension of mechanicalism in the science of our time. The question takes on a different phase when it is asked whether mechanicalism is the final word of nature, whether it is self-sufficient, in fact whether the principles of mechanicalism are themselves mechanical. This is a wholly metaphysical question and does not at all affect positive science; for the phenomena will be explained in the same way whether matter is thought of as inert, composed of little particles which are moved and combined by invisible hands, or whether an interior activity and a sort of spontaneity is attributed to them. For the physicist and for the chemist, forces are only words representing unknown causes. For the metaphysician they are real activities. It is metaphysics, therefore, and not physics which is rising above mechanicalism. It is in metaphysics that mechanicalism has found, not its contradiction, but its completion through the doctrine of dynamism. It is this latter direction that philosophy has mainly taken since Descartes and in this the prime mover was Leibniz.2
In order to understand Leibniz’s system we must not forget a point to which sufficient attention has not been paid, namely, that Leibniz never gave up or rejected the mechanicalism of Descartes. He always affirmed that everything in nature could be explained mechanically; that, in the explanation of phenomena, recourse must never be had to occult causes; so far indeed did he press this position that he refused to admit Newton’s attraction of gravitation, suspecting it of being an occult quality: while, however, Leibniz admitted with Descartes the application of mechanicalism he differed from him in regard to the basis of it and he is continually repeating that if everything in nature is mechanical, geometrical and mathematical the source of mechanicalism is in metaphysics.3
Descartes explained everything geometrically and mechanically, that is by extension, form, and motion, just as Democritus had done before; but he did not go farther, finding in extension the very essence of corporeal substance. Leibniz’s genius showed itself when he pointed out that extension does not suffice to explain phenomena and that it has need itself of an explanation. Brought up in the scholastic and peripatetic philosophy, he was naturally predisposed to accord more of reality to the corporeal substance, and his own reflections soon carried him much farther along the same line.
It is also worth noticing, as Guhrauer has said in his Life of Leibniz, that it was a theological problem which put Leibniz upon the track of reforming the conception of substance. The question was rife as to the real presence in transubstantiation. This problem seemed inexplicable upon the Cartesian hypothesis, for if the essence of a body is its extension, it is a contradiction that the same body can be found in several places at the same time. Leibniz, writing to Arnauld in 1671, says he thinks he has found the solution to this great problem since he has discovered “that the essence of a body does not consist in extension, that the corporeal substance, even taken by itself, is not extension and is not subject to the conditions of extension. This would have been evident if the real character of substance had been discovered sooner.”
Leaving aside this point, however, the following are the different considerations which led Leibniz to admit nonmechanical principles as above corporeal mechanicalism, and to reduce the idea of the body to the idea of active indivisible substances, entelechies or monads, having innate within themselves the reason for all their determinations.
- The first and principal reason which Leibniz brings up against Descartes is that, “If all that there is in bodies is extension and the position of the parts, then when two bodies come into contact and move on together after the contact, that one which was in motion will carry along the body at rest without losing any of its velocity, and the difference in the sizes of the bodies will effect no change,” which is contrary to experience. A body in motion which comes in contact with one at rest loses some of its velocity and its direction is modified, which would not happen if the body were purely passive. “Higher conceptions must therefore be added to extension, namely, the conceptions of substance, action and force; these latter carry the idea that that which suffers action, acts reciprocally and that that which acts is reacted upon.”4
- Extension cannot serve to give the reason for the changes which take place in bodies, for extension with its various modifications constitutes what is called in the school terminology extrinsic characteristics, whence nothing can result for the being itself; whether a body be round or square does not affect its interior condition, nor can any particular change result for it.5 Furthermore, every philosophy which is exclusively mechanical is obliged to deny change and to hold that everything is changeless and that there are only modifications of position or displacements in space or motion. Who does not see, however, that motion itself is a change, and should have its reason in the being which moves or which is moved, for even passive motion must correspond to something in the essence of the body moved? Besides if corporeal elements differ from one another through form, why have they one form rather than any other? Epicurus talks to us of round and hooked atoms. Why is a certain atom round and another hooked? Should not the reason be in the very substance of the atom? Therefore form, position, motion and all the extrinsic modifications of bodies should emanate from an internal principle analogous to that which Aristotle calls nature or entelechy.6
- Extension cannot be substance. On the contrary it presupposes substance. “Aside from extension there must be a subject which is extended, that is, a substance to which continuity appertains. For extension signifies only a continued repetition or multiplication of that which is expanded, a plurality, a continuity or co-existence of parts and consequently it does not suffice to explain the real nature of expanded or repeated substance whose conception precedes that of repetition.”7
- Another reason given by Leibniz is that the conception of substance necessarily implies the idea of unity. No one thinks that two stones very far apart form a single substance. If now we imagine them joined and soldered together, will this juxtaposition change the nature of things? Of course not; there will always be two stones and not a single one. If now we imagine them attached by an irresistible force, the impossibility of separating them will not prevent the mind from distinguishing them and will not prevent their remaining two and not one. In a word every compound is no more a single substance than is a pile of sand or a sack of wheat. We might as well say that the employees of the India Company formed a single substance.8 It is evident therefore that a compound is never a substance and in order to find the real substance we must attain unity or the indivisible. To say that there are no such unities is to say that matter has no elements, in other words that it is not made up of substance but it is a pure phenomenon like the rainbow. The conclusion is then either that matter has no substantial reality or else it must be admitted that it is reducible to simple and consequently unextended elements, called monads.
- Leibniz brings forward another argument in behalf of his theory of monads. This is that the essence of every substance is in force, which fact is as true of the soul as of the body. It can be proved a priori. Is it not evident that a being really exists only in so far as it acts? A being absolutely passive would be a pure nothing, and would involve a contradiction; or, by hypothesis, receiving everything from outside and having nothing through itself, it would have no characteristic, no attribute and hence would be a pure nothing. The mere fact of existence, therefore, already supposes a certain force and a certain energy.
Leibniz presses this thought of the activity of substances so far that he even admits no degree of passivity. According to him, no substance is, properly speaking, passive. Passion in a substance is nothing else than an action considered bound to another action in another substance. Every substance acts only through itself and cannot act upon any other. The monads have no windows through which to receive anything from outside. They do not undergo any action and consequently are never passive. All that takes place in them is the spontaneous development of their own essence. All that there is, is that the states of each one correspond to the states of all the others. When we consider one of these states in one monad as corresponding to a certain other state in another monad, in such a way that the latter is the condition of the former, the first state is called a passion and the second an action. There is, therefore, between all monad-substances a pre-established harmony, in accordance with which each one represents (or expresses, as Leibniz says) the whole universe. But this is ever only the development of its own activity.
In restoring to created substances the activity which the Cartesian school had too much sacrificed, Leibniz thought to contribute to the clearer distinction between the created and the Creator. He justly remarked that the more the activity of the created things is diminished, the more necessary becomes the intervention of God, in such a way that if all activity in created things is suppressed, then we must say that it is God who brings everything in them to pass and who is at the same time their being and their action (operari et esse). What difference, however, is there between this point of view and that of Spinoza? Would we not thus make nature the life and the development of the divine nature? In fact, by this hypothesis, nature is reduced to a mass of modes of which God is the substance. He, therefore, is all that there is of reality in bodies as well as in spirits.
To these five fundamental reasons given by Leibniz it will perhaps be allowed us to add a few particular considerations.
Those who deny that the essence of bodies is only in force, either admit the vacuum with the atomists, ancient and modern, or else like the Cartesians they do not admit it. Let us take up each of these positions separately.
For the atomists, disciples of Democritus and of Epicurus, or of Gassendi, the universe is composed of two elements, the vacuum and the plenum, on the one hand space and on the other hand bodies. The bodies are reducible to a certain number of solid corpuscles, indivisible, with differing forms, heavy and animated by an essential and spontaneous motion. These are the atoms which by their coming together constitute bodies.
Now it is evident that atoms in taking the place of other atoms, successively occupy in empty space places that are adequate to them, which have exactly the same extension and the same forms as the respective atoms. If at the moment when an atom is motionless in some place we imagine lines drawn following its contours (as when an object is being traced for transferring), is it not clear that if the atom were removed, we should have preserved its effigy, or a sort of silhouette, its geometric form upon a foundation of empty space? We should obtain thus a portion of space, which I will call an empty atom, in contrast with the full atom which was there before.
Now I ask the atomists to explain what distinguishes the full atom from the empty one, what are the characteristics that may be found in one and not in the other. Is it the being extended? No, for the empty atom is extended like the full atom. Is it the having a form? No, for the empty atom has a form as has the full atom and exactly the same form. Is it the being indivisible? No, for it is still more difficult to understand the divisibility of space than of the body. In a word everything which depends on extension is the same in the empty atom as in the full atom. But the empty atom is not a body and contains nothing corporeal; therefore extension is not the essence of bodies and perhaps does not constitute a part of this essence. May we say that it is the motion which distinguishes the full atom from the empty atom? But before beginning to move the atom must have already been something, because that which is nothing in itself can be neither at rest, nor in motion. Motion, therefore, is a dependent and subordinate phenomenon which already presupposes a defined essence. If we examine carefully we will see that what really distinguishes the full atom from the empty atom is its solidity or weight. Neither solidity nor weight, however, are modifications of extension; both come from force. It is accordingly, force and not extension which constitutes the essence of the body.
Turning now to those who, like the Cartesians, are unwilling to admit the possibility of a vacuum and maintain that all space is full, the demonstration is still more simple, for we may ask in what filled space, taken in its entirety, differs from empty space taken in its entirety. Both are infinite; both are ideally divisible and both are really indivisible; both are susceptible of modalities in form or of geometrically defined forms. Perhaps it will be claimed that in full space the particles are movable and can supplant one another; in this case we are back in the preceding line of argument and we shall ask in what these movable particles are distinguished from the immovable particles of space among which they move. Thus the Cartesians, like the atomists, will be obliged to recognize that the plenum is distinguished from the vacuum only by resistance, solidity, motion, activity, in a word, force.
To those who reproach the Leibnizian conception with idealizing matter too much, it may be replied that matter taken in itself is necessarily ideal and super-sensible. Of course it cannot be said that a body is only an assembly of subjective modifications. The Berkeleyan idealism is a superficial idealism, which will not stand examination; for when I shall have reduced the whole universe to a dream of my mind and to an expansion of myself the question will still remain whence comes this my dream and what are the causes which have produced in me so complicated a hallucination; these causes are outside of me and they go beyond me on every side; it would therefore be very inappropriate for me to call them myself, for the I is strictly that of which I have consciousness. The Fichtean Ich, which by reaction against itself thus produces the nicht-ich is only a complicated and artificial circumlocution for saying in a paradoxical form that there is a not-I. At most, we can conjecture with the absolute idealism that the I and the not-I are only two faces of one and the same being, which involves them both in an infinite activity; but we thus reach a position very far from the idealism of Berkeley.
To return to the idealism of Leibniz, I think it can be shown a priori that matter taken in itself is something ideal and super-sensible, at least to those who admit a divine intelligence. For it will readily be granted that God does not know matter by means of the senses; for it is an axiom in metaphysics that God has no senses and consequently cannot have sensations. Thus: God can be neither warm nor cold; he cannot smell the odor of flowers; he cannot hear sounds, he cannot see colors; he cannot feel electrical disturbances, etc. In a word, since he is a pure intelligence he can conceive only the purely intelligible; not that he is ignorant of any of the phenomena of nature, only that he knows them in their intelligible reasons and not through their sensible impressions, by means of which creatures are aware of them. Sensibility supposes a subject with senses, organs and nerves, that is, it is a relation between created things. From God’s point of view, therefore, matter is not sensible; it is, as the Germans say, übersinnlich. The conclusion is easy to draw, namely, that God, being absolute intelligence, necessarily sees things as they are, and conversely the things in themselves are such as he sees them. Matter is, accordingly, such in itself as God sees it, but he sees it only in its ideal and intelligible essence; whence we see that matter is an intelligible something and not something sensible.
To be sure we may not conclude from this point that the essence of matter does not consist in extension, for it could be maintained that extension is an object of pure intelligence quite as well as force. But without taking up the difficulty of disengaging extension from every sensible element, I wish to establish only one thing, namely that Leibniz cannot be reproached with idealizing matter, since this must be done in every system, at least in those which admit a divine logos and a foreordaining reason.
One of the most widely spread objections against the monadological system is the impossibility of composing an extended whole out of non-extended elements. This is Euler’s principal objection in one of his Letters to a German Princess and he considered it absolutely definitive because the necessary consequence of such a system would be to deny the reality of extension and of space, and to launch out thus into all the difficulties of the idealistic labyrinth. I think, however, that Euler’s objection is not at all insoluble, and that it is even possible to separate the system of monads from the system of the ideality of space. It can be shown that all the questions relating to space can be adjourned or kept back without compromising the hypothesis of the monads.
For, let us suppose with the atomists, with Clarke and Newton the reality of space, vacuums, and atoms. It is no more difficult to conceive of monads in space than of atoms; a point of indivisible activity might be at a certain point of space and a collection of the points of activity would constitute the mass which we call a body. Now, even if we grant that these points of activity are separated by space, yet when they were taken together they might produce upon the senses the impression of continuous space. Even in the case of what is called a body, say a marble table, every one knows that there are forces, that is to say, vacuums, between the parts. Since these vacuums, however, escape our sense organs, the body appears to us to be continuous, like the circle described by a moving succession of luminous points. In fact the bodies would be composed, as the Pythagoreans have already said, of two elements; the intervals (διαστ
ματα) and the monads (μóναδες); except that the Pythagorean monads were mere geometric points, while for Leibniz they are active points, radiating centers of activity, energies.
Regarding the difficulty of admitting into space forces nonex-tended and consequently having no relation to space, I grant that it is very serious. It cannot be raised, however, by those who consider the soul as a non-extended force and as an individual substance; for they are obliged to recognize that it is in space although in its essence it has no relation to space; there is, therefore, for them no contradiction in holding that a simple force is in space. If, on the other hand, it be denied that the soul is in space, that it is in the body, and even that it is in a certain part of the body, is it not clear that this would be attributing to the soul a character which is true only of God? To be sure, those who consider the soul as a divine idea, an eternal form temporarily united to an individual, might speak thus. Thus regarded, with the idealists or with Spinoza, the soul is not in space. But if the soul is represented as an individual and created substance, how can it be thought of except as in space and in the body to which it is united? Still more, therefore, in the case of monads will we be obliged to admit that they may be in space and then, as we have seen, the appearance of extension is explained without difficulty.
If, now, instead of admitting the reality of space we hold with Leibniz or with Kant that it is ideal, the system of monads offers no longer any serious difficulty, except from the point of view of those who deny the plurality of individual substances. In any case Euler’s objection evidently loses its force.
Another difficulty raised against the monadology is that it effaces the distinction between the soul and the body. This difficulty seems to me like the preceding one to be merely apparent. Because in every hypothesis, the essential distinction between the body and the soul is that the body is a composite, while the soul is simple. In order to prove that the soul is not extended the proof is offered that it is not a composite, while the body on the contrary is. Now in Leibniz’s hypothesis also, the body is only a composite, only an aggregation of simple elements. What difference does the nature of the elements make in this case? It is the whole, it is the aggregation which we contrast with the soul; and in Leibniz’s hypothesis, quite as well as in that of Descartes, the body as an aggregation is wholly incapable of thought.
Some one will reply: “granting all that, the elements are nevertheless single and indivisible like the soul itself and they are therefore of the same nature as the soul—they are souls themselves.” This last consequence is very incorrectly drawn, however.
What is meant by the words: “of the same nature”? Does it mean that the monads which compose the body are feeling, thinking, willing beings? Leibniz never said such a thing. What is the basis for affirming that the particles of my body are thinking substances? Let us look at the semblance they have to the soul. Doubtless they are like it single and indivisible substances. But what difficulty does it introduce to admit that the soul and body have common attributes? The atoms, for instance, have they not in common with the soul, existence, indestructibility, self-identity? And does the argument of the identity of the ego in contrast with the changing nature of organized matter, cease to be valid, because the atom is quite as self-identical as the soul? Indeed the indestructibility of the atom is used as an analogy to establish the indestructibility of the soul. If this common character does not prevent their being distinguished, why should their being distinguished be more difficult when they have in common a character essential to all substance, namely, the attribute of activity?
Furthermore, if the atoms of the substance, which constitutes the universe, are indivisible units, the power of thinking is not inconsistent with their conception. They may be thinking substances, and it cannot be denied that in this system a monad may become, if God wishes it, a thinking soul. If on the one hand it is not impossible, there is no way, on the other hand, of proving that it may be so. Why may there not be several orders of monads which are unable to pass from one class to another? Why may there not be monads having merely mechanical properties; others of a higher order, containing the principle of life, like plant souls; still higher sensitive souls; and finally free and intelligent souls endowed with personality and immortality? Leibniz’s system is no more opposed than any other to these orders.
If, however, by a bolder hypothesis, the possibility of a monad’s passing from one order to another be admitted, there would still be nothing here degrading to the true dignity of man, for, after all it must be recognized that the human soul in its first state is hardly anything more than a plant-soul which lifts itself by degrees to the condition of a thinking soul. Therefore there will be no contradiction in admitting that every monad contains potentially a thinking soul. Should such a hypothesis be repugnant, I still maintain that the monadological system does not force one to it, since monadism quite as well as the popular atomism can admit a scale of substances essentially distinct from one another.
Another objection which the Leibnizian excites, and one which Arnauld does not fail to raise in one of his letters, is that the system of monads weakens the argument of a first mover, since it implies that matter can be endowed with active force and consequently with spontaneous motion. Leibniz does not meet this objection in a convincing manner and says merely that recourse must be had to God to explain the co-ordination of movements. This, however, avoids the point, for the co-ordination has no relation to the argument of the first mover, only to that of the ordering and of the arrangement which is a wholly different matter. We may, however, remark that Leibniz, in order to establish the reality of the force in corporeal substance, much more frequently uses the fact of resistance to motion, than that of the so-called spontaneous motion. For instance, one of his principal arguments is that a moving body, when it comes in contact with another, loses motion in proportion to the resistance which the other opposes to it, and this is what he calls inertia. It is evident, therefore that if a substance in repose reveals itself by its resistance to motion, the argument of the first mover, far from being weakened is, on the contrary, strengthened.
Besides this, even if a spontaneous disposition to movement, be admitted in the elements of bodies, yet experience compels us to recognize that this disposition passes over into action only upon the excitation of an exterior action because we never see a body put in motion except in the presence of another. The actual indifference to movement and to repose, which at the present time is called, in mechanics, inertia, must always be admitted, whether we posit in the body a virtual disposition to movement or whether, on the contrary, the body be considered as absolutely passive; in either case there must be a cause determining the motion; it is not necessary that this first cause produce everything in the body moved, and that it should be in some sort the total cause of the motion; sufficient is it for it to be the complementary cause as the Schoolmen used to say.
Furthermore inertia must not be confounded with absolute inactivity. Leibniz showed admirably that an absolutely passive substance would be a pure nothing; that a being is active in proportion as it is in existence; in a word, that to be and to act are one and the same thing. From the fact, however, that a substance is essentially active, it does not necessarily follow that it is endowed with spontaneous motion, for the latter is only a special mode of activity and is not the only one. For example, resistance, or impenetrability, is a certain kind of activity, but is not motion. They are mistaken, therefore, who think that the theory of active matter does away with a first cause for motion, because even if motion be essential to matter, we will still have to explain why no portion of matter is ever spontaneously in motion.
In short, according to Leibniz, every being is essentially active. That which does not act does not exist; quid non agit non existit. Now, whatever acts is force; therefore, everything is force or a compound of forces. The essence of matter is not, as Descartes thought, inert extension, it is action, effort, energy. Furthermore the body is a compound and the compound presupposes a simple. The forces, therefore, which compose the body are simple elements, unextended—incorporeal atoms. Thus the universe is a vast dynamism, a wise system of individual forces, harmoniously related under the direction of a primordial force, whose absolute activity permits the existence outside of itself of the appropriate activities of created things, which it directs without absorbing them. This system, therefore, may be reduced to three principal points: 1, it makes the idea of force predominate over the idea of substance, or rather reduces substance to force; 2, it sees in extension only a mode of appearance of force and compares the bodies of simple and unextended elements as more or less analogous, except in their degree, to what is called the soul; 3, it sees in the forces not only general agents or modes of action of a universal agent, as have the scientists, but it sees also individual principles, both substances and causes which are inseparable from the material, or rather which constitute matter itself; Dynamism thus understood, is only universal spiritualism.
In this introduction I have examined the different difficulties which might be raised against the Leibnizian Monadology from the point of view of the Cartesian spiritualism. They have still to be examined from the point of view of those who deny the plurality of substances, that is, from the Spinozistic or pantheistic point of view. Here, however, come in a wholly different class of ideas, which we cannot enter upon without extending this introduction beyond measure. We will merely say that the force of Leibniz’s system is in the fact of individuality, of which the advocates of the unity of substance have never been able to give an explanation. It is true, we must pass here from the objective to the subjective standpoint, because it is in the consciousness that the individuality manifests itself in the most striking manner, while in nature it is more veiled. One’s position, therefore, should be taken in the region of the individual consciousness in order to combat Spinozism. This point of view has been particularly developed in our day by Maine de Biran and by his school. We have been content to mention it merely, not desiring to skim over a problem which is connected with the knottiest points of metaphysics and of the philosophy of religion.