Philosophy, Western

I

Introduction

Philosophy, Western (Greek philosophia, “love of wisdom”), rational and critical inquiry into basic principles. Philosophy is often divided into four main branches: metaphysics, the investigation of ultimate reality; epistemology, the study of the origins, validity, and limits of knowledge; ethics, the study of morality and the good; and aesthetics, the study of the nature of beauty and art. The two distinctively philosophical types of inquiry have been described as analytic philosophy, the logical study of concepts, and synthetic philosophy, the arrangement of concepts into a unified system.

As used originally by the ancient Greeks, the term “philosophy” meant the pursuit of knowledge for its own sake. Philosophy comprised all areas of speculative thought and included the arts, sciences, and religion. As special methods and principles were developed in the various areas of knowledge, a specific philosophical aspect separated one from another, with each concerned to answer the most basic questions about the field. This gave rise to the philosophy of art, of science, and of religion. The term “philosophy” is often popularly used to indicate a set of basic values and attitudes towards life, nature, and society—thus the phrase “philosophy of life”. Because the lines of distinction between the various areas of knowledge are flexible and subject to change, the definition of the term “philosophy” remains a subject of controversy.

Western philosophy from Greek antiquity to modern times is surveyed in the remainder of this article. For information about philosophical thought in the East, see Buddhism; Chinese Philosophy; Confucianism; Daoism; Indian Philosophy; Islamic Philosophy.

II

Greek Philosophy

Western philosophy is generally considered to have begun in ancient Greece as speculation about the underlying nature of the physical world. In its earliest form it was indistinguishable from natural science. The writings of the earliest philosophers no longer exist, except for a few fragments cited by Aristotle and by other writers of later times.

A

The Ionian School

The first philosopher of historical record was Thales of the city of Miletus, on the Ionian coast of Asia Minor (now Turkey), who practised about 580 bc. Thales was interested in astronomical, physical, and meteorological phenomena, and his scientific investigations led him to speculate that all natural phenomena are different forms of one fundamental substance (an early form of monism). He believed this substance to be water, because he thought evaporation and condensation to be universal processes. Anaximander, a disciple of Thales at Miletus, maintained that the first principle from which all things evolve is an intangible, invisible, infinite substance that he called apeiron, “the boundless”. This substance, he maintained, is eternal and indestructible. Out of its ceaseless motion the more familiar substances, such as warmth, cold, earth, air, and fire, continuously evolve, generating in turn the various objects and organisms that make up the recognizable world. The idea of the “boundless” represented the insight that if everything is to be made of one substance then it cannot be identified with any of the particular substances in the world, such as water or air, or share any of their particular characteristics. It also anticipates the modern notion of an unbounded universe.

The third great Ionian philosopher Anaximenes was also from Miletus, and may have been a pupil of Anaximander. He returned to Thales’s assumption that the primary substance is something familiar and material, but he claimed it to be air rather than water. He believed that the changes that objects undergo could be explained in terms of rarefaction and condensation of air. Thus, Anaximenes was the first philosopher to explain qualitative differences between different substances, such as water, fire, and stone, in terms of purely quantitative differences (here, in the degree of condensation of a single substance), a method fundamental to physical science.

In general, the Ionian school made the initial radical step from mythological to scientific explanation of natural phenomena; it discovered the important scientific principles of the permanence of substance, the natural evolution of the world, and the reduction of quality to quantity.

B

The Pythagorean School

About 530 bc the philosopher Pythagoras founded a school of philosophy, at Croton, in southern Italy, that was more religious and mystical than the Ionian school. It fused the ancient mythological view of the world with the developing interest in scientific explanation. The system of philosophy that became known as Pythagoreanism combined ethical, supernatural, and mathematical beliefs into a spiritualistic view of life. The Pythagoreans taught and practised a way of life based on the belief that the soul is a prisoner of the body, is released from the body at death, and is reincarnated in a higher or lower form of life, depending on the degree of virtue achieved. The highest purpose of human beings should be to purify their souls by cultivating intellectual virtues, refraining from sensual pleasures, and practising various religious rituals. The Pythagoreans, having discovered the mathematical laws of musical pitch, inferred that planetary motions produce a “music of the spheres”, and developed a “therapy through music” to bring humanity into harmony with the celestial spheres. They were the first to see mathematics as the key to understanding the world, maintaining that all things can be explained purely in terms of numbers and geometrical figures rather than in terms of a fundamental substance. Thus, the Pythagoreans were the distant forerunners of modern mathematical physicists.