Aristotle

Early Life and Education

Aristotle was born in 384 BCE in Stagira, a small Greek city on the Chalcidic peninsula in northern Greece. His father Nicomachus was personal physician to King Amyntas III of Macedon, giving Aristotle early connections to the Macedonian court and possibly sparking his lifelong interest in biology and empirical observation.

At seventeen, Aristotle was sent to Athens to study at Plato's Academy, where he remained for twenty years — first as a student, then as a teacher and researcher. Plato reportedly called him 'the mind of the school' (nous tēs diatribēs) or 'the reader.' The relationship between these two towering intellects was complex: deeply respectful but increasingly divergent. Aristotle's mature philosophy systematically criticizes the Theory of Forms while preserving and transforming many Platonic insights.

The Wandering Years

When Plato died in 348/347 BCE, Aristotle left Athens — possibly because the Academy's leadership passed to Speusippus, or because anti-Macedonian sentiment made Athens uncomfortable. He spent several years in Assos (Asia Minor), where he married Pythias, the niece of the local ruler Hermias, and on the island of Lesbos, where he conducted groundbreaking biological research with his student Theophrastus, cataloguing marine life in the Pyrrha lagoon.

Around 343 BCE, Philip II of Macedon invited Aristotle to tutor his thirteen-year-old son Alexander — the future Alexander the Great. The tutorship lasted approximately three years. The precise influence of Aristotle on Alexander is debated, but Alexander reportedly retained a lifelong interest in natural science and sent biological specimens to Aristotle from his campaigns.

The Lyceum

In 335 BCE, Aristotle returned to Athens and founded the Lyceum in a gymnasium near the temple of Apollo Lykeios. The school became known as the Peripatos (from peripatein, 'to walk'), reportedly because Aristotle lectured while walking in the covered walkway. The Lyceum was organized as a research institution: Aristotle and his students systematically collected and analyzed data in every field — constitutions of Greek city-states, natural histories of animals, records of dramatic performances, philosophical arguments.

The Philosophical System

Logic

Aristotle invented formal logic. The Organon — his collected logical works — includes the Categories (classification of types of predication), On Interpretation (propositions and their truth-conditions), Prior Analytics (the theory of the syllogism, the first formal deductive system), Posterior Analytics (the structure of demonstrative science), Topics (dialectical argumentation), and Sophistical Refutations (fallacies). The syllogistic — a system for determining which argument forms are valid — remained the dominant logic in the West until Frege's revolution in the late 19th century.

Metaphysics

Aristotle's Metaphysics investigates 'being qua being' — the most general features of reality. His central metaphysical concepts include:
- Substance (ousia): The primary category of being. Individual things (this horse, this person) are primary substances.
- Form and matter (hylomorphism): Every physical substance is a composite of form (morphē) and matter (hylē). Form makes a thing what it is; matter is the stuff it is made of.
- Actuality and potentiality (energeia/dynamis): Aristotle's solution to the Parmenidean problem of change. Change is not something coming from nothing but the actualization of a pre-existing potentiality.
- The Four Causes: Every complete explanation requires material cause (what it's made of), formal cause (what it is), efficient cause (what brought it about), and final cause (what it's for — its telos).
- The Unmoved Mover: At the pinnacle of Aristotle's metaphysics stands a necessary, eternal, immaterial being — pure actuality (energeia) with no potentiality — that moves the cosmos by being the object of desire and thought. This concept profoundly influenced medieval theology.

Natural Philosophy and Biology

Aristotle was the greatest biologist of antiquity and arguably until Darwin. He personally dissected and described hundreds of animal species, classified them systematically, and developed foundational concepts in embryology, anatomy, and ecology. His biological works (History of Animals, Parts of Animals, Generation of Animals) represent a staggering achievement of empirical observation and theoretical synthesis. He emphasized teleological explanation in biology: the parts of organisms are best understood in terms of their functions.

Ethics

The Nicomachean Ethics is the most influential work of ethics in Western history. Aristotle argues that the highest human good is eudaimonia (happiness, flourishing, living well) — activity of the soul in accordance with virtue over a complete life. Virtue (aretē) is a disposition to choose the mean (mesotēs) between extremes of excess and deficiency: courage is the mean between cowardice and rashness, generosity between stinginess and prodigality. Practical wisdom (phronēsis) is the intellectual virtue that enables right judgment in particular circumstances. The life of philosophical contemplation (theōria) represents the highest form of happiness.

Political Philosophy

The Politics begins with the famous claim that 'man is by nature a political animal' (zōon politikon). The city-state (polis) is the natural community within which human beings can fully realize their nature. Aristotle classifies constitutions by number of rulers and orientation toward common or private good, analyzes the causes of political stability and revolution, and develops his theory of distributive justice. He defends a mixed constitution and the rule of law over the rule of individuals.

Final Years

When Alexander the Great died in 323 BCE, a wave of anti-Macedonian sentiment swept Athens. Aristotle, with his Macedonian connections, was charged with impiety. He reportedly fled to Chalcis in Euboea, saying he would not allow Athens 'to sin twice against philosophy' (alluding to the execution of Socrates). He died there in 322 BCE, at the age of 62.

Legacy

Aristotle's influence has been immense and varied across cultures and centuries. In late antiquity, Neoplatonists harmonized his philosophy with Plato's. Arabic and Islamic philosophers (Al-Kindi, Al-Farabi, Avicenna, Averroes) made him 'The Philosopher' (al-muʿallim al-awwal, 'the first teacher'). Medieval Christian theology, especially through Thomas Aquinas, synthesized Aristotelian philosophy with Christian doctrine. The scientific revolution of the 17th century defined itself partly in opposition to Aristotelian physics, but Aristotle's logic, biology, ethics, and political thought remain foundational.