The word philosophy comes from the Greek words philo (which means loving) and sophia (which means wisdom). A philosopher is a seeker of wisdom, and philosophy is the study of ideas, including moral, religious, and scientific ideas. The ancient Greeks gave more than a name to this branch of study. They also created some of the most important early philosophical works and ideas. Early Greek philosophy influenced Hellenistic* scholars, who carried on the Greek tradition in various parts of the Mediterranean world after 300 B.C.

The Greeks developed severed branches of philosophy. One is ethics, the study of moral principles or values. Ethics is especially concerned with the specific moral choices an individual makes in his or her relationship with others. Metaphysics asks questions about the nature of reality and the meaning of existence. Logic, a third branch of philosophy, is the science of reasoning. Logicians study methods of expressing ideas and facts and then linking them together. A fourth branch of philosophy is natural philosophy, the study of nature and the physical world. In modern times, natural philosophy has evolved into various sciences, such as biology and physics.

Over hundreds of years, Greek and Hellenistic philosophers laid the foundations of all these branches of philosophy. They shaped the thinking of people throughout the ancient world, and their influence was long lasting. Even after the end of the Greek and Roman eras, the writings of Greek philosophers were the starting point for much of the literary, intellectual, and scientific activity of the Western world.

* Hellenistic referring to the Greek-influenced culture of the Mediterranean world during the three centuries after Alexander the Great, who died in 323 B.C.

Early Philosophers. The earliest known Greek philosophers were concerned with natural philosophy and metaphysics. In particular, they were interested in cosmology, the study of the nature of the universe. They wanted to understand how the universe and the world around them originated, what they were made of, and what forces or elements were operating in them.

Thinkers in Miletus, a Greek city on the west coast of Asia Minor, attempted to answer these questions in the 500s B.C. The first was Thales, who is sometimes called the father of philosophy. Although Thales left no written records, later writers reported that he believed that all things were made of the same basic element—water. Anaximander and Anaximenes, the next generation of philosophers in Miletus, also thought that everything in the universe came from one original substance. However, they recognized that whatever that original substance was, it must undergo many changes to appear as the great variety of things that exist in the natural world. Their inquiries were directed toward questions that would today be part of physics and chemistry.

Another early philosopher was the mathematician Pythagoras, whose followers kept his teachings alive for centuries. The Pythagoreans not only developed some basic principles of mathematics and astronomy, but they also believed that numbers had mystical* and spiritual meanings. One influential Pythagorean idea was that the soul lived forever. After death, the soul was reincarnated, or reborn in a new body. Pythagoreanism shaped the thinking of Empedocles, who was active in the late 400s B.C. Empedocles believed that all living things were connected. He urged his fellow Greeks to stop making sacrifices* of animals, although such sacrifices were central to many religious rituals*. Empedocles also taught that everything in the universe is made from four elements—earth, air, water, and fire.

Heraclitus of Ephesus and Parmenides of Elea were active around 500 B.C. Only brief, obscure statements remain of Heraclitus’s writings, such as “the way up and down is one and the same.” He warned people not to trust their senses, which can be fooled. His main contribution to philosophy was the idea that everything in the universe is constantly changing and flowing. Nothing is fixed, even if it appears solid. Parmenides inquired into the origin of the universe, asking how it could come into being from nothingness. He decided that the universe did not have a beginning but must have always existed.

Anaxagoras, who lived in the 400s B.C., was interested in natural philosophy. He considered such topics as the qualities of physical matter and the causes of growth and movement. Unlike Heraclitus, Anaxagoras believed that the senses were reliable sources of knowledge. Another philosopher interested in matter was Democritus, who worked in the late 400s B.C. He developed the first atomic theory of matter, claiming that everything in the universe was made of tiny particles, called atoms, that moved about in empty space.

The Athenian Philosophers. Beginning in the mid-400s B.C., Athens became the center of Greek philosophy. About this time, philosophical thinkers shifted their interest from cosmology to human affairs. They concerned themselves with such issues as moral behavior, the relationship between the individual and society, and the nature of wisdom. Philosophy attempted to define and educate good leaders and citizens. Rhetoric, or the art of using words effectively in writing and speaking, became an important part of education. A number of learned men, called Sophists,taught rhetoric and the various branches of philosophy in Athens.

Socrates, one of the key figures in the history of Greek philosophy, attacked the Sophists for claiming to know what moral virtue was and for claiming to be able to teach it. How could they have true understanding, Socrates asked, when each Sophist defined virtue differently? Plato, a student of Socrates and one of the most influential of the Greek philosophers, also criticized the Sophists. According to Plato, the Sophists lacked firm moral values. Although they taught their pupils how to win arguments, Plato reasoned that they did not impart real knowledge and that they explained the workings of the universe in mechanical or physical terms, without moral meaning.

Although Socrates left no writings of his own, most scholars believe that many of his ideas are reflected in the works of Plato. One of Socrates’ most important contributions to philosophy was his method of teaching, which is called dialectic (or the Socratic method). Dialectic takes the form of a conversation or a series of questions and answers. Instead of simply stating his own opinions, Socrates questioned the opinions and ideas of others, trying to expose false thinking and make people discover the truth on their own.

* mystical referring to the belief that divine truths or direct knowledge of God can be experienced through meditation and contemplation as much as through logical thought

* sacrifice sacred offering made to a god or goddess, usually of an animal such as a sheep or goat

* ritual regularly followed routine, especially religious

Plato raised metaphysical and ethical questions that have continued to attract the attention of philosophers ever since. He also established the Academy, a school in Athens that survived for centuries after his death. Many scientists and philosophers of the ancient world received their training there.

Plato’s best-known pupil, Aristotle, determined that the highest goal of human life—the activity that produced the greatest happiness—was the use of reason in the study of philosophy. In using the gift of reason to seek what is good, humans came closest to the divine. Aristotle, who taught the young Alexander the Great, founded a school in Athens called the Lyceum. His philosophy and school of teaching became known as peripatetic (which means “walking around” in Greek), because Aristotle taught while walking around with his students. Aristotle’s boundless curiosity led him into nearly every branch of philosophy and science. He wrote volumes on biology, logic, ethics, poetry, politics, and many other subjects. His writings were studied by later philosophers during the Hellenistic period in Greece and in Rome. During the Middle Ages, Aristotle’s works were highly esteemed by many Christian and Arabic scholars. St. Thomas Aquinas, one of the greatest philosophers of the period, called Aristotle simply “the philosopher.”

Hellenistic Philosophers. In the late 300s B.C., Alexander the Great conquered much of the known world. His conquests initiated a period known as the Hellenistic era, when Greek culture mingled with other cultures of the eastern Mediterranean. Although Athens remained the chief center of philosophical activity, the Egyptian city of Alexandria and other Hellenistic cities also produced important Hellenistic philosophers.

Hellenistic philosophy took a new direction. The spirit of speculation and inquiry gave way to the search for peace of mind, comfort, security, and happiness. Rival schools of philosophy competed for attention, each offering to show followers the way to “the good life.” At the same time, the sciences of geography, medicine, and astronomy flourished as researchers looked for practical results that could be applied to everyday life. Science and philosophy were beginning to have separate identities.

Epicurus founded one of the three main schools of Hellenistic philosophy. His basic idea was that all living creatures seek pleasure and that people can be guided to what is good by seeking in moderation what is pleasurable—and especially by avoiding pain and anxiety. To the Epicureans, human happiness had nothing to do with the gods. Instead, every person had the power to ensure a happy inner life by arranging pleasant circumstances—by living a life of moderation, displaying wisdom, caution, and courage, and through the joys of friendship. A person forced to endure difficult circumstances could achieve happiness by concentrating on pleasant memories.

The chief rival of Epicureanism was Stoicism, a school founded by Zeno of Citium around 280 B.C. While the Epicureans identified good with pleasure, the Stoics identified good with virtue or excellence. The Stoics developed a complex theory of matter, space, and time, but their ideas about physics were less influential than their moral teachings. According to the Stoics, people could achieve wisdom only by eliminating all emotions, passions, and affections. The Stoics believed that by observing nature, people could arrive at universal laws and principles that all reasonable beings should follow in their dealings with one another. The various versions of Stoicism that arose in the last two centuries B.C. had a profound influence on Roman thinkers.

The third major school of Hellenistic philosophy, skepticism, arose during the 300s B.C. and took many forms. Instead of putting forward ideas or beliefs, the skeptics used negative or critical arguments to attack other positions. They claimed that because so many different schools and philosophers had failed to agree on universal truths, such truths did not exist. Because no underlying realities can be known, there is no basis for a system of beliefs. The only thing of which a skeptic can be sure is the evidence of the senses. For example, a skeptic might say that honey tastes sweet to him, but he would not go so far as to say that it is sweet.

A final approach to philosophy, too simple and disjointed to be called a school or a system, was that of the Cynics. Their goal was to be self-sufficient, free of ties to family, community, or society. They saw themselves as reformers whose mission was to point out dishonesty and vice in others—a mission that made them universally unpopular. Their philosophy originated in the 300s B.C., and Cynics were numerous during the Hellenistic and Roman eras. (See also Astronomy and Astrology; Mathematics, Greek; Medicine, Greek; Philosophy, Roman; Science.)


Greek and Hellenistic thinkers were deeply concerned about the relationship between philosophy and poetry. About 380 B.C., Plato referred to "a long-standing quarrel between philosophy and poetry" concerning which field offered greater knowledge and understanding. Yet some philosophers were also poets. Parmenides and Empedocles, for example, set forth their philosophical ideas in poems. Aristotle argued that philosophical writing was superior to poetry, but he admired poetry as an art form that appealed to the emotions as well as to reason. The Stoics, on the other hand, believed that the only good poems were educational poems.

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