The Historical Development of Philosophy

New Philosophy

Monadology of Leibniz

The shortcomings of Locke's theory of knowledge were partly acknowledged by his contemporaries. However, the arbitrary distinction between primary and secondary qualities, along with the related inquiries into the criteria of objective significance for complex concepts, stirred less disagreement than the fundamental assumption underpinning this distinction: the premise that external objects must act upon the human mind and imprint either the objects themselves or, at the very least, their actions, which could be regarded as symbols of the existence of things independent of the thinking subject. This assumption was prominently criticized by the eminent philosopher Leibniz, who flourished in the latter half of the seventeenth century and the early eighteenth century. According to Leibniz, the question of how something foreign to our soul can be transmitted to it from another entity remains a mystery that Locke did not resolve but merely evaded, for he straightforwardly assumed the action of things upon the soul. Therefore, one may accept all that Locke asserted regarding the emergence of our ideas as it pertains to how they appear to us. It is entirely plausible that specific concrete ideas exist in the soul prior to abstract and universal ones, and that we relate them to the influences of the external world. However, this does not provide a metaphysical explanation for the origin of ideas; metaphysically, it is inconceivable that something could penetrate our soul that was not initially present within it. Since our self-consciousness contains only the identity of “I” with itself, without any other “I,” it necessitates the absolute independence of our spiritual existence from which it unfolds. Consequently, Leibniz wholly excludes both the direct influence of other entities on our own soul and the influence of the latter upon foreign entities. Thus, everything we commonly refer to as experience, the formation of ideas based on external empirical impressions, may be metaphysically regarded as the self-development of the soul, wherein the representations ingrained in the soul, initially vague—even to the extent of being infinitely indistinct—gradually become clearer and clearer.

According to Leibniz, our soul is the sole entity in the universe that we can directly and intrinsically know. Everything we express about other things is based on our representations of them. Thus, in reality, the entire world is confined to our representations, and we can only judge the essence of things by analogy to our own soul. From this premise emerges a general metaphysical assumption that the world represents, in general, a realm of entities akin to the soul—monads; each of these monads must be conceived as absolutely self-sufficient, such that nothing can penetrate any of them from without. However, given that we must conceive of the world as a harmonious whole, they relate to one another through their inner properties. We can only imagine these inner properties analogous to those we perceive in our own soul, specifically as the faculties of representation and striving—two fundamental properties of our spiritual being. The order of the arrangement of monads cannot be other than what we discover in our own spiritual life, which consists of a gradual transition of representations from the least clear to the most clear. Leibniz posits that we are thus compelled to recognize as essential to the world's harmony, specifically as a law governing that harmony, two principles: the first states that all things in the world are analogous to one another; the second asserts that all differences continuously transition into one another. By these two fundamental laws of continuity and analogy, the world is understood as a sequential series of infinitely many forces. Each of these forces, each monad, is not only an absolutely self-sufficient unit but also an absolutely simple essence; if a monad were composite, it would necessarily dissolve into simple forces or essences. Consequently, monads form a system of degrees, which ascends through infinitely small differences between consecutive members to infinitely great differences; these differences also manifest among individual monads in varying degrees of clarity in their representations. However, since monads, in Leibniz's vivid expression, “have no windows whatsoever,” and since nothing can pass from one to another, the totality of representations that can arise not only in an individual monad but also throughout the universe is embedded within each monad from the outset. Therefore, each monad is a “microcosm” in the true sense of the term: the entire world is contained within it, and the distinction between individual monads lies only in the varying degrees of clarity of their representations. Among monads at the lowest level, all representations are entirely vague; among those at the intermediate level, some representations are vague while others are clear; and finally, among the monads at the highest level of their hierarchy, the whole world is presented quite clearly. The first of these monads are those of inanimate nature, the second are the souls of animals and humans, while the monad at the highest level is the highest of all monads, the “monas monadum,” or God.

Thus, the system of monads, as Leibniz particularly emphasized, leads with the same internal necessity to theism, just as Spinoza’s doctrine of substance leads to pantheism, or, which was equivalent for Leibniz, to atheism. However, this assertion must be qualified to the extent that the monad of monads does not correspond to the concept of a transcendent God but rather belongs to the universe: it contains the whole world within itself. At the same time, it is evident that in this notion of the “monad of monads,” the Augustinian thought regarding the ideas of the Creator re-emerges in a peculiar modification: in these ideas, according to Leibniz, must be expressed not simply the world prior to creation, but the eternal relationship of God to the world—indeed, the concept of the monad of monads represents a further development of Plato’s doctrine of ideas, in which the subjective character of ideas, already noted by Augustine, is accompanied by the notion of their immanence in the world or, more precisely, their simultaneous transcendence and immanence. It is clear that the alteration introduced by Leibniz into the Platonic-Augustinian thought on ideas corresponds, on one hand, to his inclination towards the Aristotelian idea of development and, on the other hand, to the intermediary position between theism and pantheism that his system occupies.

Monadology is a distinctly metaphysical concept. It represents a doctrine concerning the transcendent world, which, while it can be inferred from the actual facts of our psychic life, is not directly accessible within them and rests upon the idea of harmony in its two factors: the analogy of all beings and the principle of continuity. Thus, Leibniz had to adopt a stance toward experience that was directly opposed to that of Locke. While the latter viewed experience as the foundation for resolving the problem of knowledge, Leibniz endeavored to extract the very content of experience from his presuppositions about the metaphysical world of monads. It is noteworthy that, for this purpose, Leibniz required an auxiliary concept akin to the one used by Spinoza for a similar aim, which, in all these modern systems of transcendental metaphysics, serves as a reflection of Plato's doctrine of ideas. Just as the obscurity that Platonic ideas experience in sensory things transforms, for Spinoza, into the inadequate knowledge that constitutes our empirical understanding—since we perceive individual things not as modes of existence of an infinite substance but as independent entities—so, too, for Leibniz, all our empirical knowledge is regarded as composed of confused representations, and we only ascend to clear representations when we think of God or when we enter the realm of general abstract concepts, be they mathematical or philosophical. Even the law that governs all empirical knowledge—the law of causality, or, as Leibniz refers to it, the “principle of sufficient reason”—is, therefore, a principle that can serve as guidance exclusively for the realm of confused representations; clear knowledge, on the other hand, adheres solely to the logical laws of identity and contradiction. Thus, when knowledge is divided into these two great domains, which, due to the presence of entirely different laws, have no relation to one another, it becomes all the more reasonable for Leibniz to acknowledge the significance of this mentioned auxiliary concept of empirical knowledge within its domain, just as he had already recognized Locke's theory of concept formation as empirically valid and only required it to be supplemented by a metaphysical explanation.

On these principles of Leibniz’s theory of knowledge rest the various components of his system: his philosophy of nature, psychology, theology, and ethics. It must be emphasized, of course, that Leibniz’s philosophical worldview did not arise all at once but developed gradually from the disciplines just mentioned, among which his writings on natural philosophy largely represent early stages of his thought that he later rejected. Initially, Leibniz opposed the material and spiritual worlds to one another. However, through a deeper exploration of the concept of force—where he diverged from Descartes from the very beginning—he arrived at an idealist perspective according to which the extension of bodies has significance only as an “appearance” behind which there lies a non-spatial, purely spiritual existence of the monad.

Leibniz predominantly perceives this true being of things in the notion that the essence of force can only be understood as purposeful activity. However, purposes can only be conceived as manifestations of spiritual entities that set goals. Thus, even in the teleological nature of the most general laws of nature, Leibniz discerns confirmation of this assumption. All natural phenomena can be derived mechanically from these general laws; however, they can only be understood teleologically, and thus, ultimately as spiritual forces. Consequently, Leibniz refers to monads as “entelechies” in the Aristotelian sense; among all natural laws, the law of “conservation of force,” which he himself established, is, in his opinion, the one that most clearly allows us to grasp spiritual intentionality. This law serves as an immediate expression of the idea of the unity of the world and cosmic harmony. It is evident that Leibniz formulated the law of conservation of force in full accord with the Cartesian principle of “conservation of quantity of motion.” However, he indicates that the constancy of the product mv, posited by Descartes, contradicts observed phenomena, particularly those of the motion of heavier bodies. Thus, he establishes the law of the constancy of the product of mass and the square of velocity (mv² or, according to modern definitions, “living force”—a term first introduced by Leibniz) as the true measure of the forces of nature. However, while he enters into dispute with the Cartesian school regarding this “measure of forces,” which long divided physicists into two camps, in his general cosmological views, he fully aligns with Descartes. Notably, Leibniz rejects Newton’s accepted concept of action at a distance and seeks to explain planetary motion through vortex movements of matter and phenomena of gravity through the emission of ether, among other ideas.

Ultimately, Leibniz supplemented his philosophy of nature with ideas inspired by the discovery of spermatozoa by Leeuwenhoek. He believed he found confirmation of both the principle of harmony he postulated for the universe and the idea of the “microcosm,” which he applied to individual beings. Along with many psychologists of his time, he considered the spermatozoon to be a complete organism in a state of involution. In the dispute between the “ovulists” and the “animalculists”—the followers of Harvey, who accepted development from an egg (ovulum), and the supporters of Leeuwenhoek, who traced development to the movement of spermatozoa—he decisively sided with the latter. He characterized this direction in its most extreme forms with the expression: “Non solum animae, sed animalia sunt immortalia.” According to Leibniz’s doctrine, the development of a living being proceeds continuously between involution and evolution: the soul simultaneously possesses both pre-existence and immortality, and at each stage of its being, it is connected with the ensouled substance. Consequently, the soul, in turn, represents an image of the world, a microcosm: as the central monad, it relates to the subordinate monads of its body just as the “monad of monads” relates to the totality of monads within the universe.

Based on these metaphysical and natural philosophical assumptions, Leibniz also addresses the principal problems of psychology. His perspective on nature compels him to restore the Aristotelian view, which posits that the soul is not merely a “thinking substance” but rather an “entelechy of a living body.” Thus, the soul of an animal is also akin to that of a human, representing a preceding stage in development; for indeed, “animated being” is not, in monadology, a specific attribute of any substance, but the essence of the substance itself. From this standpoint, and employing the principle of continuity—evident to him from his work in differential calculus—Leibniz resolves the problem of the interaction between soul and body, not in the Cartesian sense of direct influence between substances, nor in the occasionalist view that acknowledges God's eternal mediation. In the infinite sequential series of monads, the monads of the body are those that are closest to their respective soul, that is, to their central monad. What occurs in the soul must, by virtue of the law of continuity, also take place in the monads of the body, albeit in a more indistinct form, and vice versa. Therefore, the relationship between soul and body constitutes merely a particular instance of universal harmony: it, along with universal harmony, is a necessary outcome of the continuous gradualness of beings and their internal states. Thus, Leibniz's resolution of this problem, akin to Spinoza's, rests on the foundations of mathematical-metaphysical inquiry: just as Spinoza derives the parallelism of all modes of thought and extension from the concept of absolute infinity of attributes, so Leibniz establishes a similar parallelism from the notion of infinitely small differences among monads. However, the former's resolution is grounded in the belief that extension and thought are genuinely distinct properties, while the latter's conclusion is based on the idealistic perspective that extension is merely a form of appearance in which the universe is reflected in the perceiving being.

The thought of harmony similarly prevails in Leibniz's theology. The concept of God, according to his teaching, from two perspectives that generally dominate his system, provides the completeness of harmony: from the standpoint of the law of continuity, whereby God is the “monad of monads,” the highest of monads, in which all that occurs in others is presented in an infinitely clear form; and from the perspective of the law of analogy, according to which God is the central monad of the world, the governing spiritual force of the universe, analogous to how the individual soul is the central monad of its body. Both viewpoints, according to Leibniz, engender the idea of a transcendent God, yet one inextricably linked to the world. On the basis of this idea, he subsequently replaces the notion of universal harmony with that of pre-established harmony, according to which the order of the world is established by God, and thus the specific interactions between soul and body are predetermined by Him. In the "Essays on Theodicy," which primarily contain a theological interpretation of Leibniz's fundamental metaphysical principle, he also seeks to demonstrate the agreement of his philosophy with Christian teachings of faith, its consonance with the belief in miracles, as the latter demands only what is "incomprehensible to reason," yet "not contradictory to it," and so forth. While such attempts may arise from a sincere desire on the philosopher's part to reconcile faith and knowledge and, to the extent possible, various Christian doctrines, it must also be acknowledged that the broadly aimed studies of theodicy and the letters in which Leibniz discusses religious matters with Catholics and Protestants do not serve as reliable sources in this respect. However, the optimism evident, particularly in Leibniz's religious-philosophical inquiries, should be considered the main tendency of his views, closely linked to the aesthetic aspect of his teaching on universal harmony. When he explains in the "Essays on Theodicy" that the actual world is the best among infinitely many possible worlds, and asserts that it would be possible for God—metaphysically, not morally—to create another world, the latter can still be regarded as merely a mode of exposition chosen out of respect for the religious perspective of his reader. Yet there is no doubt that he himself believed this actual, harmony-bound world to be the best of possible worlds; in this sense, the significance of moral convictions should primarily be acknowledged in his views regarding the necessity of the opposition of suffering and joy, good and evil, for the realization of perfection.

This optimism ultimately dominates Leibniz's ethics. Man is inherently good. The evil within him is not a positive reality but a limitation, a deficiency arising from confused representations, thus fundamentally rooted in the very order of the world, but negated through a sequential series of beings. The same law of harmony and continuity, which binds beings together and awakens the desire within individual monads to transition from obscure representations to clear ones, impels man to love his neighbors and assist them, embedding within him the need for perfection.

In this practical application, the reconciling nature of Leibniz's philosophy prominently emerges. In his own words, as one who is more inclined to agree with others than to contradict them, Leibniz sought to reconcile religion and philosophy, empirical and rational modes of thought, theoretical contemplation and the necessities of practical life. However, in its fundamental direction, Leibniz's system is as speculative as that of Spinoza; it too revives the ideas of the Renaissance: the microcosm and the principle of analogy from Paracelsus, monads, the monad of monads, and the universal harmony of Bruno. Despite this, the peculiarity of Leibniz's system lies in the fact that it brings order, establishing a strict logical connection and thus raising to a coherent, systematic unity those thoughts that, in the philosophy of the Renaissance, existed as brilliant intuitions. This enabled the two systems, whose principles merged into one another in the undeveloped ideas of Renaissance philosophical systems, to stand in full opposition to each other in their sequential development. This opposition manifests in many respects. Spinoza's worldview is a combination of realism, universalism, and pantheism: it is realism because it recognizes the immediate reality of the fundamental properties presented in external and internal experience within the attributes of extension and thought applied to substance; it is universalism because it denies individuality autonomy, acknowledging the absolute reality of a singular all-encompassing substance; it is pantheism because it understands God and the universe in an indivisible unity. In contrast, Leibniz's system is idealistic, individualistic, and theistic: it is idealistic because it acknowledges only the spiritual properties given in immediate internal perception as real; it is individualistic because it proclaims the absolute autonomy of individual entities—monads; it is theistic in that the highest monad is self-sufficient, thus distinct from the world itself.