Plato's Philosopher-King & Aristotle's Substance

Plato's Philosopher-King

The Ideal City

For Plato, the philosopher-king is essential for a just society. In The Republic, he presents a hierarchical society divided into three groups:

• Craftsmen: Provide resources like food through productive work.
• Guardians/Warriors: Defend the city from internal and external threats. This class is crucial as it produces the leaders, who are the best guardians. They live a distinct life, without private property, family, or typical housing, and women marry within their class.
• Philosophers: Rule the state. Plato believed philosophers, possessing knowledge of ideas and reality, are best suited to govern. These leaders are selected based on physical and psychological excellence.

Plato's ideal city is founded on Truth, Justice, and the Good. His argument for the philosopher-king rests on these premises:

• Objective knowledge is attainable.
• Not everyone can achieve this knowledge.
• Only those who achieve it are qualified to lead.
• The Science of the Good is part of philosophy.

Aristotle's Concept of Substance

Defining Substance

Substance, derived from the Latin substantia (translation of the Greek ousia), refers to something independent of its predicated attributes. It signifies:

• The subject of properties (e.g., Socrates, who is Athenian, Plato's teacher).
• What persists through accidental change (e.g., Socrates remains the same despite aging).
• Independent existence (e.g., Socrates, a stone, or a tiger exist independently, unlike attributes like "white" or "small," which depend on a substance).

Types of Substance

Aristotle distinguishes two types of substance:

• Primary Substance: Individual subjects, compounds of matter and form (e.g., Socrates).
• Secondary Substance: Genera and species (e.g., human, animal, plant).

When we ask "What is this?" we seek the nature of something—its substance. The answer can be a primary substance (e.g., this specific book) or a secondary substance (e.g., a book). Secondary substance describes the nature of things as species and genera. Socrates is a primary substance, while "man" is his secondary substance.