Plato’s Philosophy: Ideas, Soul, Knowledge, and Ethics

Posted on Dec 18, 2024 in Philosophy and ethics

Duality of Worlds

Plato presents a duality of worlds:

  • Physical: Particular objects, characterized by continuous change.
  • Ideas: Ideas in themselves, the truly real. These ideas are intelligible and are the essence of things. They are separate from the physical but exist in themselves. The way to discover them is through thinking, and they are therefore subject to scientific study. Each idea is unique, eternal, and unchanging, unlike physical entities, which are limited representations of the ideas as their model. A relationship of presence exists between ideas and physical things.

Critical Review

Faced with problems such as what kind of ideas are there?, what is the relationship between ideas and things?, or is there a hierarchy of ideas?, Plato claims the existence of ideas based on these reasons:

  1. The world of ideas is the foundation of the sensible world, as it must remain true and immutable.
  2. The properties of sensible things are limited, with regard to the universal, to ideas.
  3. Science can only treat the immutable and universal.

Cosmology

Demiurge: An entity that shapes a chaotic and eternal material mass within existing space. For this, it uses the model of eternal ideas. Plato believed that the cosmos is a sphere, with Earth at the center, then the spheres of the planets, and everything surrounded by the sphere of fixed stars. The whole movement is based on musical harmonies and numerical proportions.

Soul

Plato establishes a duality between body and soul, which constitutes the human being. The soul is immortal and united to the body while seeking purification. It is divided into:

  1. Rational: Immortal, the source of intelligence, located in the brain.
  2. Irascible: Mortal, the source of noble passions, located in the thorax.
  3. Appetitive: Mortal, the source of ignoble passions, located in the abdomen.

The only part that separates from the body at death is the rational soul, created by the Demiurge. After several incarnations, it returns to the world of ideas. The body is a hindrance to the soul.

Knowledge

Plato initially uses the theory of reminiscence, which states that we already knew but have forgotten. The soul contemplates the ideas, obtaining certain knowledge, but upon reuniting with the body, it forgets what it learned in the world of ideas. During a lifetime, a person remembers what they learned through experience. Therefore, knowing is remembering. However, in subsequent dialogues, this theory is replaced by the simile of the line, which divides knowledge into:

  1. Opinion: Formed by imagination (the lowest grade), responsible for images of sentient beings, and belief, which takes beings themselves.
  2. Science (highest level): Subdivided into dianoia, which is mathematical discourse that uses visible images to deductively draw conclusions, and noesis (the highest), which is the intelligence that leads to true knowledge of the Ideas.

Ethics

Ethics is focused on justice, the chief political virtue. Teachers who teach about justice are the Sophists. Plato defines virtue as wisdom, the scope of the philosopher. He also defines it as harmony between the parts of the soul, which can only be achieved if the rational soul governs reason, the irascible governs mood, and the appetitive governs appetite. Thus, a person is just. Other moral virtues are:

  1. Prudence: Choosing what is appropriate in each case (related to the rational soul).
  2. Fortitude: Performing difficult actions (related to the irascible soul).
  3. Temperance: Controlling the pleasures of the senses (related to the appetitive soul).

Politics

In a state, there are three requirements: economic, defense, and government. Society is divided into three classes:

  1. Producers: Responsible for immediate needs, providing tools and trade.
  2. Guardians: Defend the state.
  3. Rulers: Responsible for organization.

The rulers have the most developed rational soul and the virtue of prudence. Guardians have the irascible soul and the virtue of fortitude. Producers have the appetitive soul and the virtue of temperance. If everyone plays their role, society is just.

Historical Context

Plato’s thought developed during the 5th century BCE, during the Hellenistic period. In Greece, the polis, independent city-states, were established. The traditional form of government was the monarchy, which drifted into oligarchy. However, social problems and the excesses of the oligarchs led to tyranny. Athens adopted direct democracy as a form of government. Pericles was one of the creators of this form, granting rights of isonomy and isegoria. Athens was in crisis due to the Peloponnesian War, being defeated. The economic base was agriculture and maritime trade. There was a boom in literature, sculpture, and architecture. Schools of rhetoric, mathematics, and philosophy were created. Plato was influenced by Socrates and inherited the conflict with the Sophists. He was also influenced by pre-Socratics and Parmenides.