History of Philosophy

Ancient Philosophy

Plato

The most distinguished philosopher of Antiquity, who wielded the greatest influence on all subsequent philosophy, was Plato (427-347 BCE). He lived in Athens, was a student of Socrates, founded his own school called the Academy, and authored numerous works in the form of dialogues. Several key themes stand out in Plato's philosophical teachings:

• Doctrine of Ideas: Every object in the world is created according to a specific plan. Initially, there is a plan, project, or idea of the object, and only afterward does this idea manifest in the object itself. Just as no object appears without its idea, so too could the world not appear without its idea. Each thing is the realization of ideas; thus, the world itself is a realization of ideas. Ideas are pure and immutable essences. They represent true being, as spoken of by Parmenides. Ideas are unchanging, unlike objects, which are subject to change. For instance, one can alter the shape of a square object to become triangular or circular, but this does not change the essence of the square. Even if no square objects remain in the world, the idea of the square would still persist. However, without the idea of the square, there could be no square objects, as the square is not derived from square objects, but rather the reverse. Eternal and immutable ideas can be known only by the mind, not the senses. For example, one can see a rectangular table, but the rectangle itself can only be conceived. The material world is merely an expression of ideas.
• Doctrine of the Good: Ideas exist in a strict hierarchy. For instance, "color" is a more general concept than "red," and thus the idea of color is hierarchically superior to the idea of red. If ideas occupy different hierarchical levels, it implies that there must be an idea at the highest point of this hierarchy. Since ideas are true being, the highest hierarchical idea is absolute being, and all other ideas existing at lower hierarchical levels exist only to the extent that they express the highest idea. The highest idea must be something present in all things. The universal for all that exists is the Good. This led Plato to assert that the highest hierarchical idea and absolute being is the Good. Thus, Plato reiterated and refined the core idea of Eucleides of Megara regarding the identity of Socratic Good and Parmenidean Being.
• Mathematics: To create an object, it is insufficient to know merely its shape; dimensions are also necessary. The same applies to the world. For ideas to be expressed in the formation of the world, mathematical categories are essential. Plato was profoundly influenced by Pythagoras and his attempt to merge philosophy with mathematics. Since all ideas are expressed through numbers, everything in the material world is subordinated to numbers. There is no physical or chemical quantity that cannot be measured.
• Doctrine of Man: If everything in the world is an expression of eternal ideas, then humans, being part of the world, are expressions of the idea of humanity. As an idea, humanity existed in the world of ideas, where it observed the true essences of all that exists. However, having deviated from the contemplation of truth, it became distanced from the contemplation of ideas. As it moved further from true being, it assumed coarse material forms. Plato believed that the material world is a consequence of humanity's fall from the contemplation of ideas. Thus, human souls became ensnared in material bodies, which act as prisons limiting the freedom of spirit by bodily needs.
• Doctrine of the Soul: The human soul is not a monolith. Plato distinguished three parts within it. The rational part of the soul motivates a person to act wisely and virtuously. The passionate part of the soul proposes irrational and harmful decisions. The appetitive part of the soul neither initiates behavioral decisions nor enacts them, but merely implements the decisions made by the rational and passionate parts. When the rational part of the soul governs, the person's life is wise and successful. If governed by the passionate part, the life becomes wicked and futile.
• Theory of Knowledge: Plato confronted the question of why humans think in general concepts when they experience individual instances. For example, everyone knows that all trees can burn, though no one has ever seen all trees burning. At most, people have seen individual pieces of wood burning. Nevertheless, this is sufficient to conclude that all trees can burn. If the human mind makes correct inferences that do not arise from experience, it means that experience is not the source of knowledge. So where does knowledge come from? Humans saw the truth in the world of ideas, where they existed before entering their bodies. When humans entered their bodies, their knowledge became mixed. However, by observing things created in the likeness of ideas, they recall the ideas themselves. Thus, experience is not the source of knowledge but merely a means of actualizing it. Plato provided an answer to the question that Socrates left open. Socrates asserted that the human mind possesses knowledge prior to encountering experience but did not explain where the mind obtained this knowledge. Plato clarified this issue.
• Ethics: A person achieves moral perfection only when they attain moral excellence in all aspects. One cannot be moral in some manifestations while immoral in others. Since the human soul consists of three parts, all three must achieve moral excellence, i.e., virtue. For the rational part, virtue is wisdom, as it is tasked with wisely managing human life. For the passionate part, virtue is temperance. Plato did not call for a complete renunciation of the impulses of the passionate part of the soul but required them to be kept within strict limits. Thus, a person should rest, eat, and entertain themselves, but all must be in moderation. If these exceed reasonable bounds, they will ruin human life. For the appetitive part of the soul, virtue is courage. Since its role is to implement the impulses of the other two parts, even the best impulses of the rational and passionate parts will be meaningless if the appetitive part lacks sufficient courage to act upon them. When a person achieves wisdom, temperance, and courage, becoming good internally, their external manifestations become good as well; they achieve social virtue—justice—which shapes their moral attitude towards others. In the Middle Ages, Plato's virtues (wisdom, temperance, courage, and justice) were called cardinal virtues and entered the Catechism of the Catholic Church under this name.
• Politics: Plato, like all ancient Greeks, believed that a person is a microcosm (a small world) and thus contains everything present in the macrocosm (the great world). If the human soul consists of three parts, then the soul of the state (the society) must also be divided into three classes, each with the same characteristics as the corresponding parts of the soul. The rational part of the soul in the state corresponds to the philosopher-kings, that is, wise and educated individuals tasked with governing. Plato emphasized that when an uneducated populace governs, the state is doomed to collapse, and the people to misery. The passionate part of the soul corresponds to farmers and artisans. Just as the passionate part constantly seeks, so too do farmers and artisans continually accumulate material goods. Farmers and artisans must be confined within clear limits, just as the passionate part of the soul must be. If they exceed their bounds and take on governance, the state will be ruined. In an ideal state, everyone should engage in what they are suited for and not take on roles for which they lack the skills and abilities. The appetitive part of the soul in the state corresponds to the warriors, who must be sufficiently courageous to defend the country. Plato attempted to develop a model of the ideal state in which everyone would be happy. In his state, philosopher-kings and warriors should not own private property, as this would lead them to prioritize personal interests over those of the state. Farmers and artisans, on the other hand, should own private property, for if they did not possess the means of production and the products of their labor, they would lose the will to work. To ensure everyone’s happiness, all decisions should be made by educated specialists, i.e., philosopher-kings. They decide what people should eat, how they should dress, what music to listen to, etc. By having all decisions made by experts, these decisions are the best. However, the ideal state left no room for human freedom.