Main Philosophical Directions

Directions of Epistemological Theory

Objective Idealism

Idealism is generally understood as any worldview that regards the spiritual content of life as the primary or sole value and acknowledges that the substance of things is spiritual existence. Therefore, at the foundation of idealism lie predominantly practical motives. In this context, the concept of value plays a guiding role. While materialism and largely realism primarily focus on understanding the world, idealism seeks to evaluate individual phenomena according to ethical needs; hence, evaluative judgments often participate in resolving epistemological issues. Considering the foundations that determine the initial emergence of various metaphysical directions, their mutual relationship can be characterized as follows: in materialism, the drive for knowledge prevails; in idealism, ethical interests dominate; and realism attempts to give equal attention to both. Additionally, there is a distinction in the theoretical interests themselves. If materialism emphasizes the understanding of the external world, for idealism, the starting points are the human being, their life, origins, fates, and hopes; realism strives to investigate both sets of questions evenly. This relationship among materialism, idealism, and realism is evident in the successive systems of ancient philosophy: in the earliest naïve materialistic cosmology, there is a predominance of a general explanation of nature; then, in the first idealistic system, that of Plato, the main focus shifts to anthropological and ethical issues; finally, in Aristotle's realistic system, natural scientific and anthropological problems undergo thorough investigation.

Idealism already arises at the stage of pre-scientific and particularly mythological thinking. Every primary mythology serves as part primitive explanation of the world and part ethical-religious worldview. If the explanation of nature finds its expression primarily in myths about nature, then ethical-religious contemplation predominantly manifests in the representations of gods as arbiters of human fate and protectors, embodying human joys and sufferings, hopes, and fears. Since this worldview is closely tied to ethical-religious contemplation, at this mythological stage, the underlying directions of various worldviews can only be delineated according to prevailing aspirations. However, in Greece, even at the mythological stage, these two aforementioned directions early become opposed: alongside the myth of nature from popular religion, as it appears in Homer's tales of the gods, there is the cult of mysteries, representing a substantially different religious form. While the Homeric gods express a joyfulness that reflects humanity's primary interest in the sensory world in all its manifestations, the Dionysian and Orphic mysteries turn attention to the world beyond the earthly realm. In these cults, characterized by alternating ecstatic elevation of spirit and profound decline, the hopes and fears of the human soul striving beyond the terrestrial world find characteristic expression. Both directions of mythological thinking persist in the nascent philosophy. The ancients already saw the cosmological reflections of the Ionian physicists as a further development of cosmological myths, where the myth of nature in its various forms is connected with the problems of the world's origin. On the other hand, the Pythagorean school formed a union whose religious aspirations were intricately woven with those of the Orphic cult, focusing from the outset on questions regarding the afterlife and the fate of the soul post-mortem. Both directions begin to converge in their ethical tendencies, as cosmological contemplation becomes at odds with the myth of nature and its anthropomorphic representations of the gods, a contradiction that first emerges in the Eleatic school. This struggle against popular mythology among the Eleatics, akin to Heraclitus, is associated with the aspiration to counter the flux of phenomena with a unified concept that expresses the essence of things. The more the concepts of a resting being and the continuous flow of things, in their inaccessible closure, exclude any attempt to relate them to the world of phenomena, the more the opposition between reality and concept becomes evident, akin to the opposition between the sensory world and the fruits of human desires and hopes—the suprasensory world as it forms the foundation of the Pythagorean doctrine of immortality. Thus, both in the Pythagorean teachings and in those of the Eleatics and Heraclitus, the tendencies to transcend the primitive materialism characteristic of ancient reasoning arise even in the cosmological period of Greek philosophy. These aspirations, as the final decisive factor, were joined by a revolution in philosophical thought, prepared by sophistry and ultimately brought about by Socrates, resulting in a philosophical interest centered on humanity, primarily because from this point on, self-knowledge became regarded as the paramount task of philosophy, focusing on its spiritual existence. From these three factors—the Pythagorean teaching about the suprasensory world, the conviction in the possibility of knowing in concepts the essence of things liberated from sensory illusion, and finally, Socratic teachings on the absolute value of the spiritual aspect of humanity—idealism developed in its most influential form: Platonic idealism.

The evolution of this idealism in detail was further determined by its position concerning preceding directions: its negation of skepticism and the sensationalism of the sophists, on one hand, and its opposition to the materialism of the preceding natural philosophy, on the other. In contrast to skepticism and sensationalism, Plato proclaims the universal significance of any true knowledge, which by its nature represents knowledge in concepts. In opposition to materialism, he teaches that spiritual existence, which appears in the sensory world only in imperfect forms, constitutes the essential content of knowledge. The arguments employed by Platonic idealism in refuting the aforementioned directions, which differ from it in various respects, can be summarized in three points.

1. The existence of opinions subjectively necessitates the existence of knowledge as its necessary correlate, and knowledge, in turn, presupposes objective truth as its content. The object of opinions is the mutable sensory world; thus, the object of knowledge must be the immutable suprasensory world, the world of ideas.
2. The concepts that exist in our minds indicate the existence of objects that are commensurate with them, just as sensory perceptions point to sensory objects outside ourselves. Sensory perception is changeable, as its objects are mutable; however, concepts, containing the commonality of a range of mutable perceptions, are constant. Therefore, their objects—ideas—are immutable; and since in a concept we comprehend the essence of the object, the idea must objectively embody the essence of the thing. Consequently, concepts and sensory perceptions relate to each other as being relates to a phantom.
3. Every human action presupposes and necessitates the existence of a higher good. This higher good in the sensory world is attainable only approximately. Indeed, it can only be realized in the suprasensory realm; conceived in relation to the mutable goods of the sensory world as a singular and unchanging good, it equally represents a constant concept indicating an unchanging, eternal idea as its object. Just as the concept of the good is the most perfect of all concepts, so the idea of the good must be the highest of ideas, and thus, as the supreme object of the suprasensory world, it is identical with the idea of divinity.

The first of the three arguments presented here is directed against the teaching of the sophists, who asserted that only opinions exist and that true knowledge, in any case, does not. The second argument is aimed at the materialist natural philosophers, who recognized the sensory qualities of things as their true essence: according to the dialogue "Sophist," they believed in the possibility of knowing everything through external senses. The third argument simultaneously targets both skeptics and materialists, opposing their common assertion that the existence of a super-sensory world is unprovable and that all human goods lie within the realm of the sensory.

As a result of this inquiry against the aforementioned currents, objective idealism emerged. Plato's ideas are spiritual objects and, at the same time, archetypes of actual things. In analogy to the relationship between true knowledge and opinions, and concepts and sensory perception, one can think of the relationship between the super-sensory world of ideas and the sensory world. Concepts relate to their objects—ideas—in the same way that sensory perceptions relate to sensory objects. Ideas, manifesting in sensory things, become obscured, making sensory things imperfect representations of ideas in the same way that sensory perceptions are imperfect and mutable imprints of concepts. Ideas, as objects, exert influence on the intellect in the same manner that sensory objects do on the senses. The distinction here lies solely in the fact that sensory objects directly act upon the senses, whereas the intellect is compelled to action through thought. Therefore, in Plato's view, the process of concept formation, which has its initial basis in intellectual contemplation of the objects of concepts, occurs through thought, with sensory perception serving as the initial cause that prompts thought to gradually recall the first intellectual contemplation. Thus, the process of knowledge is enclosed within the boundaries between sensory and intellectual contemplation, with dialectical thought serving as the mediating link between the two. In this mediating role of thought, the position of humanity between the sensory and super-sensory worlds is revealed; from this position, in turn, the nature of the human soul becomes clear: the soul, as the principle of life, encompasses that spiritual activity through which the transition from sensory contemplation to intellectual contemplation is achieved, and thus it must primarily belong to the super-sensory world, the source of intellectual contemplation of ideas. Accordingly, the soul must be eternal, like the ideas. Its pre-existence is a theoretical postulate because the emergence of concepts presupposes the soul's recollection of ideas; its existence after the destruction of sensory being is practical, as the highest good, which the soul tirelessly seeks due to the notion of good inscribed within it, must be attainable for it. Since, however, this good is not attainable in the sensory world, the existence of the soul after death must be admitted, when it directly possesses the highest good.

From this position of the soul between the sensory world and the world of ideas, the direction in which Plato resolved three principal problems of philosophy—cosmological, psychological, and ethical—begins to take shape. Among these, the cosmological problem found resolution last, as he emphasized psychological and ethical questions from his idealistic perspective. Moreover, the resolutions of cosmological problems in Plato are expressed in such poetic and mythological forms that the connection with the principles of the doctrine of ideas can be outlined only in general terms. This connection primarily manifests in Plato's teaching that the soul, as the link between humanity and the world of ideas, embodies ideas in sensory things in the form of a world soul; a teaching that Plato, cloaking in mythological form, expresses as follows: the creator of the world, the demiurge, who represents something intermediate between God and the world, shapes sensory things according to the archetypes of ideas. To vividly illustrate this creative activity, Plato employs a concept borrowed from mathematical constructions, a representation that led him to return in this realm to Pythagorean cosmology. If the ancient Pythagoreans conceived numbers—of which they believed all things were composed—in spatial forms as perfect geometric figures, then Platonic philosophy, due to the movement of its thought in the realm of concepts from which the doctrine of ideas arose, formed abstract concepts of numbers from these vivid representations, which, in relation to ideas, are termed "ideal numbers." Already in this form, they played a role in the later Pythagorean school, which was influenced by Plato's thought. Therefore, we can understand Plato's cosmological myth, as presented in the "Timaeus," in the following philosophical terms: the formation of the world is viewed here as a process in which spatial forms, which are sensibly apprehensible but simultaneously reflect concepts, are formed according to the model of pure, abstract, that is, non-sensibly perceptible concepts. This relationship of ideal numbers or abstract numerical concepts to real numbers and proper spatial forms is something Plato could consider an example entirely suitable for understanding the relationship between ideas and sensory things in general.

A significantly different task faced the philosopher in resolving the psychological problem and its ethical implications. Here, he had to progressively unveil the mental faculties through which the activity of ideas is gradually realized in human consciousness. Striving to satisfy this general requirement through direct psychological investigation, Plato arrives at his teaching on the parts of the soul. The examination of mental faculties concerning the ideal perfection required of them gave rise to his concepts of virtues. Finally, the transference of all these concepts, derived from individual human life, onto the state led him to his doctrine of the ideal political structure.

Since practical requirements occupy a central place in the doctrine of ideas, for which theoretical reasoning was only to provide necessary justification, it is evident that in Plato's idealism, this first form of idealism, the evaluation of goods and the desire to reform life according to ethical ideals played a significant role in its emergence. From a theoretical standpoint, this objective idealism permits dualism in two respects: first, the dualism of ideas and sensory things, where knowledge still retains a naive character, and in the teaching of recollection, ideas are thought of analogously to sensory things; and second, the dualism of body and soul, where the latter is regarded as an intermediary link between the world of ideas and the sensory world, which must possess existence independent of the latter and which, therefore, strictly speaking, loses the significance of an intermediary link. This, in turn, calls into question the idea of immortality, which is based on the pre-existence of the soul and its existence after the death of the body.

The shortcomings of Platonic idealism have already been noted, in part, by Aristotle. In striving to eliminate these flaws and more fully meet the demands of empirical reality, he is the first to arrive at realism within his system, while still retaining two idealistic elements from Plato's worldview: the transcendent idea of God and the notion of the active intellect. Both of these elements are idealistic because they rest on the concept of pure, immaterial form, which, from a metaphysical standpoint, shares essential features with the notion of the Platonic idea. However, the epistemological grounding that Aristotle provides for both of these ideas imparts a realistic character to them: neither of these pure formal concepts is known through an act of recollection, nor through an immediate dialectical process of thought; they represent the final terms in a series of developments occurring within the realm of sensory and empirical experience. Just as cosmic movements presuppose a first mover, which does not arise from any new movement, so the processes of the soul, ascending from sensory perception to pure thought, presuppose a spiritual activity that does not combine, like others, passive suffering with active endeavor, but instead represents a pure activity that is, at the same time, the pure essence of spirit. In both cases, in the concept of God and in the notion of pure reason, real development thus requires the introduction of idealistic elements, although this direction does not, as a whole, become idealistic. However, in the introduction of these idealistic elements, practical motives again play a guiding role, manifesting on the one hand in the demand for a pure monistic conception of God, and on the other in the desire to provide a philosophical foundation for the idea of immortality. Just as idealism, in general, has its source primarily in ethical rather than theoretical concerns, so too do these idealistic additions to the realistic system arise from a striving to satisfy ethical needs; this can also be observed in the subsequent philosophical systems of the Stoics and Neoplatonists, who partially revert in their cosmological speculations to the primitive materialism of ancient natural philosophy.

Like the last systems of Greek philosophy, Christian worldview initially intersects with Platonic idealism from an ethical standpoint. However, since it does not in any way represent metaphysics in the philosophical sense, but merely a system of faith, the internal coherence of its concepts is of little importance: the amalgamation of idealistic and materialistic perspectives is even more characteristic of faith the greater the contradiction it presents with knowledge in concepts. Nevertheless, due to spiritual needs, whether unconsciously or intentionally, self-reflection emerges prominently in contrast to rational knowledge, exerting significant influence on the development of idealism. Christian epistemology and cosmology primarily strive to satisfy religious needs. Thus, epistemology in Christianity transforms into a doctrine of faith, while cosmology becomes a doctrine of redemption: it is not the sage, as in ancient philosophy, but the believer who possesses the truth; the question of the origin of the sensory world is not at the forefront, but rather the question of achieving bliss in the supersensory realm.

This transformation of worldview is most clearly evident in the thinker of the patristic period who is closest to the idealistic direction—Augustine. The essential differences of this Christian idealism from the Platonic idealism that is related to it and which greatly influenced it, are, in accordance with the change in overall perspective, primarily reduced to three points.

1. In Christian teaching, ideas no longer form a hierarchical system of independent entities, with the idea of God at the top; they are transformed into thoughts of God, existing in the divine spirit prior to creation; in the human spirit, they manifest as concepts under the influence of external realities. Alongside this, the original ideas themselves transform into concepts. They arise in the human spirit through reflection on the thoughts of God, through a process that bears no resemblance to the process of sensory contemplation. Creation, according to this teaching, does not arise from the mixing of ideas with sensory substance: it flows from the Word, from the thought of God, in all its parts, both in form and substance. However, it does not represent, as in Plato, a simple shaping of chaotic matter; it is creation ex nihilo. In God, thought precedes the sensory thing; in our knowledge, on the contrary, the thing precedes thought.
2. Beings that occupy an intermediary position between God and the world, which Neoplatonism assigns a mediating role between pure being of ideas and the sensory world, also find a place in the Christian worldview: the need for the redemption of the believing soul necessitated their inclusion. However, they are transformed here from cosmic potentials into spiritual and moral forces, with all of them, and especially the one in which the thought of redemption concentrates, the Logos, becoming personal beings similar to humans; the redemption accomplished by the Logos is his personal free act just as human sinfulness, the fall, is the product of his own free action. Along with this, the Platonic view that evil arises from the mingling of pure ideas with matter is dismissed, and thus, it appears from the very beginning of creation: according to Christian teaching, creation emerges from the hands of God completely pure; evil is not a cosmic, and therefore necessary, process, but an historical event, stemming from the deviation of free human will from the divine, and thus at the end of history, a return to the purity of the original creation is possible.
3. Since every creative force, including the force that shapes substance, is transferred to the divine, the soul ceases to play a mediating role between ideas and the sensory world. It itself transforms into the thought of God and thus stands alongside other created things. At the same time, it becomes a substance and, as a result, is incorruptible, just like every created substance of God. Consequently, the doctrine of the preexistence of the soul, rooted in Platonism, disappears from view; conversely, the immortality of the soul, which for Plato is based solely on ethical demands and the analogy with the preexistence of the soul, acquires an independent metaphysical foundation in the newly formed concept of spiritual substance.

In the period of scholasticism, Christian idealism, which has emerged from the interplay of Christian religious convictions and ancient, predominantly Platonic, philosophy, and has reached its climax in the Augustinian system, did not undergo significant changes. However, in the very late era of scholasticism, under the influence of an expanding interest in secular sciences and the Aristotelian philosophy responding to these new demands, it acquires a realistic shade; consequently, classical scholasticism of the 13th century presents itself as a contradictory metaphysical system. The idealistic crown of the old Christian system still remains; however, it stands as a crown upon a realistic edifice that can no longer support it. In the most influential of the scholastic systems, that of Thomas Aquinas, this realistic transformation of Christian ideas can be observed from three perspectives: in the inclination towards a fully empirical theory of knowledge, in the return to the Aristotelian concept of the soul as the principle of life, and in the supplementing of religious and ethical requirements, the so-called theological virtues, with empirical morality that satisfies worldly needs. This disintegration of Christian idealism under the penetrating influence of realism and empiricism is most sharply expressed in the theory of knowledge, where these directions do not merge with one another, as is the case in psychology and ethics, but where the empirical perspective necessarily leads to the acknowledgment of the dogmas of faith, such as creation, the Trinity, and redemption, as purely mystical and inaccessible to knowledge, and to the acceptance of a relationship between knowledge and faith only in that experience can at least point to transcendent ideas, for instance, in the cosmological proof of God's existence in nature as an indication of the creator. Here, the complete rupture between knowledge and faith is already being prepared, which ultimately led, in nominalism, to the union of philosophical sensualism and even materialism with religious mysticism.

In stark contrast to the realism and empiricism of the later scholastic period, the initial phase of Renaissance philosophy witnessed the emergence of idealism, which significantly returned to its Platonic roots. This idealism, enriched by Neoplatonic ideas and characterized by a poetic and fantastical nature, found itself teetering on the precipice between mythological poetry and genuine philosophy, ultimately unable to forge a new form of an idealist system. Thus, the worldviews of Paracelsus and Giordano Bruno oscillated between idealism and materialism, individualism and universalism, theism and pantheism. At this juncture, the distinctions among these views were not yet fully recognized; instead, decisions regarding acceptance or rejection of various perspectives were often guided more by immediate sentiments than by logical considerations. Nevertheless, these new directions, leaning predominantly toward idealism, diverged from the earlier Christian and original Platonic idealism in one crucial aspect: they were imbued with a prevailing interest in natural philosophy. In this respect, the idealism of the Renaissance intersected with the nascent natural sciences.

In the philosophy of the seventeenth century, as the influence of natural science grew—primarily serving as a stage for the development of new directions—realistic currents began to dominate. Among these, Cartesian philosophy stands out as the most significant phenomenon in terms of its impact on the subsequent development of both idealism and materialism. While the materialist systems of the eighteenth century rightfully pointed out that Cartesian natural philosophy, with its consistent embrace of a mechanistic worldview, had already paved the way for their emergence, Descartes’ dualistic philosophy, through its metaphysical principles and psychological perspectives, also became a foundational point for a new idealism. Two elements of Descartes’ system held particular importance in this regard. First, the concept of the soul, which Descartes borrowed from ancient Christian philosophy and developed further. By understanding the soul as a substance in a more precise sense than Christian philosophy did and attempting to define it more clearly through its opposition to material substances, Descartes became the creator of the modern conception of the soul, which posits it as a singular, indivisible essence, the primary attribute of which is the activity of thought—an activity that fundamentally coincides with will. Consequently, the activity of thought stands in stark opposition to the purely passive nature of matter, which, moreover, is characterized by continuous, infinite extension, unlike the non-extended soul. The second significant idea for the emerging idealism lies in the doctrine of ideas; Augustine’s teachings serve as the intermediary between Descartes and Plato. In Augustine, ideas are the thoughts of God, realized in creation and subsequently contemplated by the human intellect in conjunction with the influence of experience. In contrast, Descartes, under the evident sway of the ontological speculations of early scholasticism, grants priority to those ideas that are not merely thoughts of God, realized in creation, but which are innate to the human spirit from the very beginning, thus understood as necessary. These include intuitively apprehensible ideas, ideas of our own “self,” mathematical properties of bodies, and the idea of God. All these ideas substantiate their reality in the third, the idea of God, for the concept of an infinite being cannot originate from the human spirit itself but must be imparted to it by God, the absolute certainty of whose existence simultaneously serves as a guarantee for the veracity of the other aforementioned ideas, which we also grasp with clarity and distinctness. Hence, such ideas are intrinsic to the human spirit as much as to the divine, preceding all experience. Therefore, they alone possess unquestionable truth, while sensory representations, arising from experience, are clouded by an illusion rooted in sensuality. Thus, in Descartes’ thought, the predominant dichotomy characteristic of Plato reemerges between the world of being and the world of appearances. However, under the combined influence of the new natural science, which mechanically explains phenomena, the revised understanding of the soul—already prepared by ancient Christian philosophy—and the ontological proof of God’s existence, this dichotomy acquires a different content: it no longer constitutes a contrast between the ostensibly objective ideal realm and the sensory world, but rather delineates various subjective modes of representation situated within human knowledge of the actual world. This actual world is singular. In its true being and in its dependence on God, it presents itself to us in clear ideas; the sensory specter, on the other hand, results merely from an imperfect understanding of the same world. If, therefore, the imperfection of the Platonic sensory world arose from the fusion of ideas with matter, the deceptive specter, the world of appearances in Descartes, finds its origin in the connection of the soul with the body. Thus, the indicated dichotomies of being and appearance, a priori and empirical knowledge, which played a significant role in the development of the new idealism from this time onward, attest to the changes that gradually transpired in Christian speculation regarding the concepts of matter and soul, ultimately leading Descartes to transform both concepts into substances possessing opposing properties.

From this point, two currents of idealistic metaphysics emerged in the subsequent development of philosophy, which partly retain their influence to this day and which first took shape in sharply defined worldviews at the beginning of the eighteenth century. The first of these currents, founded upon the new conception of the soul and the doctrine of two ways of knowing, introduced objective idealism in a new form through Leibniz’s monadology, which markedly deviated from Platonic idealism. The second current expressed itself in subjective idealism, a phenomenon particularly characteristic of the new philosophy, first finding its expression in the philosophy of Berkeley.

Leibniz's system of objective idealism represents a necessary and consistent development of the new substantial conception of the soul, applying to it the fundamental principle of idealism that sees the actual being of things in their spiritual content. Under this understanding, the individual soul, presented to us in immediate subjective experience, necessitates the assumption of a multitude of spiritual beings akin to itself. Furthermore, as natural phenomena fundamentally manifest a variety arising from the confluence of numerous distinct manifestations of forces, it is likewise essential to posit the existence of multiple substantial unities. By defining the intrinsic nature of these unities, or monads, as psychic, based solely on the singular instance when they are revealed to us in direct inner experience, one can easily derive all further implications of monadology by applying to each individual monad the concept of substantiality obtained from preceding philosophy, thus resolving arising contradictions between metaphysical understanding and experience by reducing them to the opposition between being and appearance. The notion of substance demands the constancy and eternity of monads. From the constancy of the monad follows that its states, which, being psychic, reduce to desires and perceptions, are not produced in it by anything external but arise in the process of the self-development of monads from their own inner being; from this self-development, in turn, it follows that all relations between monads must rest on their original inner harmony, stemming from the principle of continuity applicable to all that exists; a particular instance of this harmony represents the concord between soul and body. The eternity of monads entails not only their immortality but also their pre-existence: here, the revived objective idealism necessarily reverts to idealism in its original form, to Platonism. Like Plato’s world of ideas, in which the idea of the good reigns supreme, so in Leibniz’s philosophy, God is the highest of the monads, the pinnacle of an infinite continuous series of monads. The understanding of nature in Leibniz’s system is greatly aided by the principle of the opposition between the world of being, consisting of simple substances, and the world of appearances, given in our representations.

In the phenomena of nature, existence unfolds not as it truly is, but as it appears in our vague sensory perceptions. Yet this world of appearances, which we comprehend according to the principle of sufficient reason, contains within it an indication of the world of being. The mechanical laws governing all of nature, such as the law of equality of action and reaction, particularly the law of conservation of energy, exhibit a purposeful character; every establishment of goals presupposes spiritual causes.

Among all forms of new idealism, Leibniz’s idealism, being objective, is closest to that of Plato. Its distinction lies in the transformation of the hypostatized concepts and ideas of Plato into individual thinking beings, or monads, due to the changes wrought upon the notions of soul and spirit by first Christian and then Cartesian philosophy. Thus, Leibniz’s system of idealism constitutes a pure synthesis of Christian and Platonic views. Where these views cannot be reconciled, contradictions emerge within Leibniz’s system. These contradictions are most evident in his understanding of the relationship between God and the world: in many of his philosophical writings, the highest of the monads serves as the final link in an infinite chain of monads, akin to the idea of the good in the realm of ideas, while in most of his theological writings, the monads of the world are seen as emanations from the one divine monad, the primordial thoughts of creation in the sense of Augustine’s system.

Furthermore, in Leibniz’s idealism, there exists a characteristic feature arising from mathematical investigations: the transference of the boundaries attributed by Plato to sensibility from the objective world into the realm of subjective knowledge. This transference holds the key to the replacement of the opposition between being and the ghostly, a dichotomy first emphasized by the Eleatics and prevalent throughout ancient philosophy, with the opposition between being and phenomenon, which plays a tremendous role in the new philosophy. In establishing this new opposition, Leibniz’s system of objective idealism runs parallel to Thomas Hobbes’ opposing system of objective materialism. Both systems complement one another: for Hobbes, transcendental matter constitutes true being, whereas for Leibniz, transcendental spiritual monads are acknowledged as true existence. In Hobbes’ view, the immediate content of spiritual life is regarded as "appearance," while for Leibniz, the entirety of our empirical knowledge about the material world is considered an "illusion" resting upon indistinct representation.