Aristotle

Aristotle was a Greek philosopher and scientist, a student of Plato and the teacher of Alexander the Great. He wrote on an extraordinary range of subjects, including logic, metaphysics, ethics, politics, biology, and poetics, and his work shaped Western thought for more than two thousand years.

Life

Aristotle was born in 384 BC in Stagira, in northern Greece. His father was physician to the king of Macedon, and Aristotle may have been exposed to medicine and biology from an early age.

He joined Plato's Academy in Athens at about the age of seventeen and remained there for some twenty years, until Plato's death. He later tutored Alexander, the son of Philip II of Macedon, and founded his own school, the Lyceum, in Athens.

He died in 322 BC in Chalcis. His writings that survive are largely the notes and treatises used in teaching, rather than the polished works he published in his lifetime.

Logic

Aristotle is regarded as the founder of formal logic. He developed the theory of the syllogism, in which a conclusion follows necessarily from two premises, and he analysed the forms of argument and the sources of error.

His logical works, known as the Organon, established the framework for reasoning that dominated until the development of modern logic in the nineteenth and twentieth centuries.

Metaphysics

In metaphysics, Aristotle developed the theory of substance and of the four causes. He distinguished the material, the efficient, the formal, and the final causes, and he argued that the understanding of a thing requires the knowledge of all four.

He also developed the concepts of potentiality and actuality, and he argued for a prime mover as the source of motion. His metaphysics provided the framework for much of medieval philosophy and theology.

Natural Science

Aristotle wrote on biology, physics, and cosmology, and his observations of animals were extensive and influential. He classified animals and described their anatomy and behaviour, and his work remained a source of knowledge for centuries.

Some of his physical theories, including the view that heavier bodies fall faster, were later corrected. His emphasis on observation and on the classification of knowledge influenced the development of science.

Ethics and Politics

In ethics, Aristotle argued that the good life consists in the exercise of virtue, and that virtue is a mean between extremes. He emphasised the role of habit and of practical wisdom, and he analysed the nature of happiness and of friendship.

In politics, he analysed the constitutions of many city-states and argued that the best constitution depends on the circumstances. He held that the state exists for the sake of the good life and that the citizen is defined by participation in rule.

Legacy

Aristotle's influence on philosophy, on science, and on theology is immense. His works were preserved and studied in the Islamic world and in medieval Europe, and they provided the framework for scholastic philosophy.

His ideas were challenged by the scientific revolution and by later philosophy, but his questions and his methods continue to shape the disciplines he founded.

The Organisation of Knowledge

Aristotle organised knowledge into disciplines and wrote treatises on each. His works were arranged by later editors into the corpus that has come down to us, including the logical works, the physical works, the metaphysical works, and the ethical and political works.

He distinguished the theoretical sciences, which aim at knowledge for its own sake, from the practical sciences, which aim at action, and from the productive sciences, which aim at making. This division of knowledge influenced the organisation of the university curriculum.

He also developed a method of inquiry that began with the observation of particular cases and proceeded to general principles. His method influenced the development of empirical science.

Physics and Cosmology

Aristotle's physics held that the natural state of terrestrial bodies is rest, and that motion requires a cause. He explained motion in terms of the actualisation of potential, and he distinguished natural motion from violent motion.

His cosmology placed the earth at the centre of the universe, surrounded by spheres that carried the heavenly bodies. The motion of the spheres was eternal and circular, and it was caused by the prime mover.

Some of these theories were later corrected, but his framework dominated the study of nature for centuries.

Biology and Classification

Aristotle's biological works are among his most original contributions. He observed and described many species, and he classified animals according to their characteristics, including their mode of reproduction and their habitat.

He distinguished animals with blood from those without, a division that corresponds roughly to vertebrates and invertebrates. He also studied the development of embryos and the behaviour of animals.

His biological work was based on observation, and it was influential for centuries. It was superseded by later research, but his approach influenced the development of the biological sciences.

Rhetoric and Poetics

Aristotle wrote on rhetoric, the art of persuasion, and on poetics, the analysis of literature. His Rhetoric analyses the means of persuasion and the structure of argument, and it influenced the teaching of rhetoric for centuries.

His Poetics analyses tragedy and epic, and it introduced the concepts of mimesis, of catharsis, and of the unity of the plot. It is the source of much of the later theory of drama and of literature.

Summary

Aristotle's work covers the whole range of knowledge and shaped the disciplines he founded. His philosophy, his science, and his logic provided the framework for Western thought for more than two thousand years.

See also

• Plato
• Socrates
• Alexander the Great