Plato’s Philosophy: Ideas, Soul, and Politics
Ontology: Theory of Ideas
Theory of Ideas: The acceptance of absolute realities, eternal, immutable, universal, and independent of the world we perceive through the senses. Concrete things in this world are just, beautiful, or good due to their participation in absolute ideas of justice, beauty, and goodness. They are imperfect realizations of these absolute ideas.
Platonic ideas are realities that exist independently of things.
Aristotle believed that the doctrine of ideas resulted from Heraclitus’ arguments that the sensible world is constantly changing. Plato tried to justify scientific knowledge against the objectivity and skepticism of the Sophists. If reality is constantly changing, no knowledge is possible with these characteristics. It is impossible to give a valid definition of these objects, and the sensible world cannot support science, understood as objective, infallible, and universal knowledge. Therefore, Plato established the existence of realities beyond the sensible, permanent realities (“ideas”).
Ontological Dualism
Plato makes a doubling of the world into the sensible and intelligible worlds:
Intelligible World: An invisible reality, only grasped by intelligence, providing true knowledge, as ideas are the true reality. Ideas are the essences of things. For example, a thing is beautiful thanks to the idea of Beauty because it imitates or participates in the idea itself. The world of ideas is organized hierarchically, with the idea of Good at the top. Plato compares this idea to the sun illuminating the intelligible world.
Sensible World: Visible and perceptible reality to the senses. Plato links this to the world of ideas through the metaphors of “participation” and “imitation,” saying that things in the sensible world “share” or “copy” the intelligible world.
Procedures to Discover Ideas
Reminiscence: Plato believed that knowing is remembering. Before coming to this world, the human soul lived in the intelligible world of ideas and saw them. Entering the world of sense and joining the body, it forgets what was known in the prior existence. This knowledge is retained by the soul and can be retrieved by memory.
Dialectic: The process of accessing the world of ideas.
Erotic Impulse: An emotional kind of dialectic.
Platonic Anthropology
The fundamental problem for the Greeks was the existence of the soul and its nature.
The concept of the soul in Greek thought is linked to two interrelated facts. While Aristotle emphasized the life aspect, Plato emphasized the intellectual aspect of knowledge. However, they are interrelated; Plato did not ignore the vital role of the body, and Aristotle did not disregard the intellectual activity related to the soul.
Plato’s rationality grasps the knowledge of ideas, which constitute the realm of the soul. For Plato, the soul is immortal, its place is the world of ideas, and its activity is the contemplation of these ideas. The union with the body is an accidental, transient state from which the soul must be liberated.
Plato considered the body a prison for the soul because, unlike the soul, it is imperfect, mutable, and belongs to the world of sense. Plato clarifies the leadership role of the soul over the body and the accidental nature of their union through metaphors.
When a person dies, the soul is judged, and those purified completely leave for the region of eternal ideas, where they will be happy.
Epistemology
In Plato’s Republic, the simile of the line illustrates four levels of knowledge. Plato invites us to imagine a line divided into two unequal parts, each subdivided into two more pairs, resulting in four subsections representing the four divisions in increasing order:
Noesis: Understanding of the Good
Dianoia: Mathematical reasoning
Pistis: Belief in sensible objects
Eikasia: Imagination of shadows and images
Moral Theory
For Plato, ethics aims for individual happiness, found in the practice of virtue. Virtue is the path to goodness and justice and equates to purification. A virtuous person purifies their soul’s passions and follows the body to access the world of ideas. Plato assigns a virtue to each part of the soul:
Rational Soul: Wisdom and prudence
Irascible Soul: Courage
Concupiscible Soul: Temperance
A good life consists of each part of the soul performing its function. Justice is the balance of the three parts.
Political Theory
Greek life was communal, divided into city-states. Society enables human development. Plato viewed the state as a large human body, with its parts corresponding to the soul. Thus, there is a need for:
Governors: A class of rational guides for society. Plato believed philosophers should govern because they possess the highest form of knowledge, the knowledge of the Good.
Warriors: A class defending the state, courageous and disciplined in their submission to the rulers, representing the irascible soul.
Workers: A class providing financial and material needs for the entire social body, representing the concupiscible soul.
Plato draws a parallel between justice in the city and justice in the individual. An individual is just when all parts are in harmony, and justice in the state is harmony between the classes as parts of a whole.
Forms of Government
A monarchy or aristocracy is the most perfect and ideal form of government, guided by wisdom. The decline of this scheme leads to timocracy, the government of the military class, whose main objective is the pursuit of honor and ambition. The degeneration of timocracy results in oligarchy, where a small minority eager for riches tightly holds power and oppresses the citizens. Tired of such abuses, the citizens overthrow the oligarchs and establish democracy. However, as the people are unprepared to rule, disorder arises, leading to a tyrant who suppresses freedom, resulting in tyranny, the most unjust form of government.