The Historical Development of Philosophy

Greek Philosophy

Platonic Philosophy

If the Socratic schools represent merely known aspects of Socratic teaching, pushing them to their extremes, then Plato, conversely, transcends the boundaries of the Socratic spirit. Nevertheless, Plato received not only the initial impulse from his teacher but also a profound direction for his thought; this is evident in the fact that he often places his own convictions in the mouth of Socrates—an unparalleled expression of respect in history. Thus, the Platonic Socrates is not the historical Socrates, but rather an idealized figure and, at the same time, a representative and interpreter of Platonic philosophy. Plato's earlier dialogues, which contain traces of direct imitation of actual Socratic discussions, also bear witness to the fact that his philosophy has its starting point in the further development of Socratic ideas.

This is further confirmed by the evolution of Platonic philosophy, which, to some extent, proceeds in the opposite direction compared to the trajectory of Greek philosophy. Initially, Platonic philosophy engages with ethical problems, which remain dominant and pivotal in its further development, shaping its overall metaphysical worldview. In Socrates, such a worldview was entirely absent due to the anthropological focus of his thought; however, Plato develops it during the second period of his philosophy, predominantly drawing from the preceding systems of the Eleatics and Heraclitus, allowing him to transform the ethical worldview borrowed from Socrates into an objective representation of the world. In the third and final period of his philosophical activity, he ultimately returns to the ancient Pythagorean teachings, utilizing them to sketch a plan of the universal order in a mystical-poetic form. The center of this development—considered a preparatory work for what precedes it and a further elaboration and completion of what follows—constitutes the doctrine of Ideas from the middle period of Plato's philosophical activity, one of the most brilliant and, without a doubt, one of the most significant philosophical creations of all time.

If Socrates taught that self-knowledge is the source of all understanding, and that the dialectical method, as it manifests in the discussions of thoughtful and inquisitive individuals, represents the proper path to such self-knowledge, then Plato regards as the sole worthy object of study the concept that emerges as the result of such inquiry. Every knowledge begins with sensory representation. However, this initial content of knowledge is mutable; it changes with the alterations of subjects and time; its result, therefore, does not represent truth but rather an opinion that misleads. It is unsurprising that the Sophists, reducing all knowledge to sensory perception, conflated knowledge with subjective opinion. Only concepts derived through reasoning possess the constancy that liberates them from changeability, thereby rendering them the substance of genuine knowledge.

Moreover, every knowledge requires an object: it becomes knowledge only when it is not merely subjective but has an adequate object corresponding to it. Thus, a concept, as the content of knowledge, must have an object that relates to it as the archetype does to its reflection. This archetype of the concept is the Idea. However, since we are presented in the sensory world only with sensory objects, the archetypes of sensory perceptions, the Idea represents a supersensible object. Hence, through our concepts, we come to know the supersensible world; in this manner, the existence of concepts serves as direct evidence of the existence of a supersensible realm, and the formation of concepts, which can occur through dialectical movement, establishes a connection between the sensory and the supersensible worlds. The sensory world is an illusory realm, as the Eleatics have already discovered; it is a world inevitably dominated by change, as Heraclitus has articulated. In contrast, the supersensible world is eternal and unchanging. However, contrary to the Eleatics' belief, it is not entirely separate from the sensory. The latter is not merely a phantom; it is a phantom only to the extent that it pretends to be reality. In the light of thought, which moves in concepts, it is, instead, a phantom that points to being and becomes the true form of being if we rise from sensory perception to the idea that conceals itself behind it.

Three questions arise concerning the implications of the metaphysical significance of concepts: 1) how is it subjectively possible that our concepts are images of Ideas? 2) what is the objective relationship of Ideas to sensory things? and 3) what order and regularity prevail in the realm of Ideas themselves?

The answer to the first of these questions follows from the fact that the process of concept formation is carried out by the human soul. Since concepts are images of supersensible objects, Ideas from which they derive their abstract universality, distinguishing them from sensory things, the soul must contemplate the Ideas. However, this contemplation must take place in a time preceding the union of the soul with the body. Thus, the soul itself, the principle that animates the body, connects the world of Ideas with the sensory world; it does not belong to either the Ideas or the sensory realm but exists between the two, such that during its existence in connection with the body, memories of ideal objects corresponding to these things are revived in relation to the influence of sensory objects. Therefore, the formation of concepts is an act of recollection: dialectical thinking, which finds the constant significance of the mutable sensory representation, is the process through which the soul recalls its own previous pre-earthly existence and simultaneously contemplates the Ideas. In this way, the process of concept formation simultaneously attests to the eternal nature of the soul, encompassing both preexistence and immortality, a nature that aligns with the soul's property as the animating principle of the body; for life excludes death just as being excludes non-being.

From this dual relationship of the soul to the sensual world and the world of ideas, we can derive an answer to the second question, that of the relationship between ideas themselves and sensory objects. As the mediating principle within humans, through which memories of the archetypes of sensory things arise in relation to sensory representations, the soul must also be conceived as an active force present within sensory objects, shaping them according to the archetype of ideas. Just as the human soul provides ideas to the body in the form of sensory perceptions, so too must there exist soulful forces in the external world that create sensory objects by shaping matter according to the archetype of ideas. Matter cannot exist on its own; it is awakened to actual existence only through the ideas that reflect within it. Thus, although ideas possess an independent existence in the supersensual realm, matter entirely lacks such existence. It is merely a negative principle; its activity is manifested solely in the limitations imposed upon ideas by its involvement with sensory objects. Herein lies the source of the disdain for the sensual world, already articulated by Plato and further developed in later Platonism, which manifests in the opposition of matter as a principle of evil to idea as a principle of good, leading to the perception of the sensual world as having fallen from the immaculate world of ideas, with the connection between the human soul and the body regarded as a state of humiliation and sinfulness. However, Plato himself counters this perspective with a reconciling thought that illuminates the sensual world through the world of ideas residing within it, that is, the understanding of beauty: this represents the most perfect expression of the idea in sensory form, forming a sequential order that begins with bodily beauty, fully immersed in the sensual, ascends through the intermediary stage of the beauty of the soul, which more purely reflects the world of ideas, and ultimately culminates in the beauty of the ideal world itself. In the human soul, this action of beauty is manifested in love, as it evolves from sensual love to spiritual love. Upon encountering beauty, it resembles the god of love, Eros, as portrayed in Plato's mythology, leading the soul into divine ecstasy and awakening in it a passionate yearning for the ideal world—initially arising as a vague premonition within sensual love, but then igniting in philosophical understanding as a bright flame of spiritual love towards the ideas themselves.

As Plato equates the relationships between ideas and sensory perceptions on one hand, and ideas and sensory objects on the other, he also objectifies the concept of the soul. Alongside the human soul, the world soul emerges as a general mediator between the realm of ideas and the sensory world; it is also appropriate to refer to the human soul as a reflection of this world soul, in the sense that while both the individual and world souls are vivifying principles connecting ideas to matter, the world soul possesses a more comprehensive significance. However, regarding this cosmological problem, the poet-philosopher had to refrain from furthering this analogy; thus, in the "Timaeus," he presents the formation of the world in the form of a mythological narrative, drawing upon ancient Pythagorean notions: the predominance of numerical relationships in the world and the formation of elements from perfect geometric forms. Following the archetype of ideas, the Demiurge shapes individual things from chaotic matter, first creating the world soul as a non-corporeal, permeating, and animating force, emerging from numerical relationships and transmitting them to all that comes into being. In this manner, the elements (fire, water, air, earth) are proper geometric bodies composed of triangular planes; the universe itself is a system of spheres concentrically arranged around the Earth as the center, upon which the stars are located. Here, Plato opposes the Pythagorean system of the cosmos, with its conception of the Earth and all stars revolving around a central fire, to the geocentric system that was further developed by astronomers of the Platonic school and later dominated under the name of the "Ptolemaic system of the world."

Just as the cosmological problem can be resolved only in general outlines based on the doctrine of ideas, with specific details left to conjecture and poetic creativity, so too the third question we posed—the question of the regularity within the world of ideas—cannot be definitively resolved. To address this question, Plato’s thought suggests that the world outside ourselves is objective, while our concepts are a subjective representation of the world of ideas. As we acknowledge the concept of the good as the highest and most perfect among our notions and thus strive to realize its predominance in the external world, it necessarily follows that in the realm of supersensual ideas, the idea of the good must be dominant. However, how the other ideas relate to the idea of the good is a question Plato never directly addressed; under the influence of conflicting motives, he offers various solutions regarding the extent to which sensory things correspond to ideas. If the sensory world must be an adequate reflection of the world of ideas, then for every individual, even the most base and vile, there must exist a corresponding ideal archetype within the realm of ideas. On the other hand, if the world of ideas is to be a perfect realm, then the individual, with its limitations and baseness, cannot find a place within it. In his earlier expositions of the doctrine of ideas, when Plato's dialectical perspective was dominant, he leans toward the former understanding; in his later developments of this doctrine, when ethical and aesthetic motives prevail, he leans towards the latter understanding, whereby ideas exist solely for the universal and the perfect.

In these fluctuating views regarding the system of ideas, one point remains firmly established: the good is the idea that stands at the head of the system of ideas, and thus, as the world of ideas reflects in the physical realm, it must also reign in our will and actions, as well as outside ourselves, in the state. This predominance of the good is represented in the relationship among three faculties of the soul: reason, feeling, and desire. Since reason directs feeling and governs desires, it dominates the other parts of the soul, guiding them towards the knowledge of the good. Similarly, among the virtues corresponding to the distinct faculties of the soul, the virtue of reason—wisdom—takes precedence, thus it must preside over the other virtues: courage, the virtue of feeling, and temperance, the virtue of desires. By uniting with the latter, the virtue of reason also produces a fourth virtue—justice.

Manifesting in the harmony of the soul’s faculties and their virtues, the ethical order of the arrangement of ideas ultimately reveals itself in the structure of human society, in the state, and indeed, the more perfect the latter’s organization, the more accurately it reflects this order. Therefore, the perfect state, in its division of organs, should resemble the relation of human spiritual faculties and virtues. In this way, the state will mirror the world of ideas itself. Wisdom, embodied in philosophers—those who dedicate their lives to knowledge—must reign within it. Following them should be the class of guardians, who embody courage and defend the state from the attacks of enemies. The lower class consists of farmers and artisans, who are tasked with implementing the third of the virtues—temperance.

Encompassing both the inner world of the individual and the outer world, both sensory and complemented by the supersensual, as well as the nature of the individual and the organization of human society, Platonic philosophy stands as the first universal system to emerge in history; at the same time, it remains the most influential to this day. The central idea of the doctrine of ideas not only became the starting point for many subsequent systems but also profoundly impacted religious worldviews, primarily within Christianity. Yet, in the period immediately following, the influence of this philosophy was partly displaced by the emergence of Aristotelian philosophy, which soon followed and often competed with it for dominance.