Plato: Biography, Philosophy, and Key Concepts
Plato (427-347 BC): Life and Philosophical Journey
Born in Athens to prominent families linked to the old nobility, Plato was a friend and disciple of Socrates. After Socrates’ death, Plato traveled extensively, eventually founding the Academy in Athens (387 BC). He attempted to implement his political ideals in Syracuse on multiple occasions but ultimately failed. Plato directed the Academy until his death and was the teacher of Aristotle.
Core Philosophical Concepts
Soul (Psychē)
Principle of life and rational knowledge. Plato maintained a tripartite soul conception: rational soul (intelligence), irascible soul (spirit), and concupiscible soul (appetite). The rational soul, often identified with the soul itself, is immortal and aims at truth and knowledge of the Good.
The Good (Agathon)
Supreme idea, the cause and basis of all reality, truth, and intelligibility. Knowledge of the Good is accessible only through intelligence and is essential for rulers to organize the polis (city-state).
Science (Episteme)
Infallible, true, universal, and necessary knowledge, concerning authentic reality, intelligence, and immutable ideas. Science is intellectual contemplation of ideas, achieved through the dialectical method.
City-State (Polis)
Sovereign and self-sufficient social and legal structure, allowing harmonious human development through law. The polis is governed by citizens and a common constitution, a set of laws governing rights, duties, and interests.
Myth
A form of understanding based on sensory perception and belief, inferior to knowledge but superior to imagination.
Dialectic (Dialektikē)
Method of apprehending authentic reality through ideas, argumentation, and dialogue. Dialectic is the highest discipline, leading to the highest knowledge (science), and is essential for philosophical education, especially for those who govern.
Education (Paideia)
Integral process of formation, leading citizens from ignorance to knowledge, encompassing physical, intellectual, and moral development. Education is a gradual process, especially for future rulers, conducted under state supervision.
Rulers
Citizens who govern the polis. Plato proposed that rulers should be philosopher-kings and -queens, selected after a long educational process, living communally without family or private property, and dedicated to the common good.
Imagination (Eikasia)
Lowest form of knowledge, dealing with images of sensible things, corresponding to the state of prisoners in the allegory of the cave.
Intelligence (Nous)
Human faculty that captures immutable essences and authentic reality. Intelligence leads to truth, while opinion deals with appearances. Science and discursive thought are forms of intelligence.
Justice (Dikaiosynē)
Virtue of a structured entity, achieved when each part performs its proper function. A just human being has a wise rational soul, a courageous spirited soul, and a temperate appetitive soul. A just polis has wise rulers, courageous warriors, and temperate producers.
Intelligible World
Realm of essences, being, and Ideas. Ideas are subsistent, immaterial, unchanging, and eternal realities, captured by intelligence. They are the models for sensible things.
Sensible World
Imperfect, multiple reality, the object of perception. Sensible things participate in or mimic Ideas, which are their models. The sensible world is known through opinion.
Opinion (Doxa)
Sensory knowledge, aimed at the changing physical world. Opinion includes belief and imagination and provides imperfect knowledge of apparent reality.
Discursive Thought (Dianoia)
Form of knowledge, higher than opinion but lower than science. It involves rigorous reasoning from premises to conclusions but does not guarantee the truth of the premises.
Wisdom (Sophia)
Virtue of the rational soul, based on truth and knowledge of the Good. Wisdom allows individuals to govern their lives and the polis effectively, guiding towards the good.