The influences of philosophy, however hard to see, are far-reaching and of great importance.

In fact, written philosophy began at about the same time civilizations began to keep written records. The history of writing and the history of philosphy often, in fact, have gone hand in hand: when the nature of writing has changed, there have been major changes as well in philosophy, from handwriting to mass production of books and then to the computer age.
Though the cultures that first developed philosophy were not in close contact with each other at the time, most of them developed philosophy at about the same time in history: the 5th-7th centuries B.C.
In the West, the Greeks developed the first major philosophical systems starting about 600 B.C. Towering figures in philosophy--Socrates, Plato, and Aristotle (ca. 470-322 B.C.)--soon followed.
Socrates was put to death by his fellow Greeks for influencing the youth of his country with too much questioning and doubt, for he encouraged everyone to question all their beliefs, no matter how sacred or important.

Plato developed orderly systems of philosophy for moral, political, aesthetic (the arts), intellectual, and spiritual behavior. He especially developed a belief in Ideas: eternal, perfect forms, invisible but understood by the soul.
For example, a baseball is but an imperfect earthly version of the eternal Idea of Roundness or Spheroid Nature.
Aristotle, though Plato's pupil for twenty years, developed a different philosophy that emphasized human reasoning, de-emphasized belief in souls or eternal forms, and was more interested in analyzing and classifying what already exists in reality.
In the nearby Middle East, Jewish religious writers were creating the Hebrew Scriptures--what would become for Judaism its foundation and Bible, for Christianity the Old Testament, and for Islam important teachings and history.
The first written Greek references to Jews refers to them as a race of thinkers. As philosophy, the Hebrew Scriptures have in them a consistent belief in a single divine being, one who can be personally contacted and who helps humanity by ethical codes and divine intervention.
In addition, later books such as Proverbs and Ecclesiastes contain philosophical reflections, and the book of Job is a profound meditation on the meaning of life and suffering.

The Song of Solomon also is sometimes given importance as a philosophical meditation on the meaning of beauty and love.
Another scholarly Islamic philosopher and one of the towering minds of the both the Middle East and the West in medieval times was Averroes (Ibn-Rushd), 1126- 1198.
He was perhaps the most important medieval commentator on Aristotle. Averroes tried to show how both belief in religion and belief in Aristotelian science could exist together.
Averroes suggested, as do some people today, that there are two realms of truth: one governed by spirituality and one governed by science. Averroes not only profoundly influenced his Muslim followers but also deeply affected some of Christianity and Judaism's greatest thinkers at that time.
In Judaism, the scholarly use of Greek philosophy to help explain religion began early. Philo (ca. 20 B.C.-50 A.D.), an Alexandrian Jewish leader, and other Jewish commentators started this process in the same time period when Christianity was being born.
One of the people whom the Muslim philosopher Averroes especially influenced was the great Jewish philosopher Moses Maimonides (Moses ben Maimon), 1135-1204. Maimonides, a Jewish rabbi (minister and teacher), codified Jewish scriptures and writings to make study of them easier.

He also developed Averroes' work with Aristotle by turning Aristotle on his head and showing how Aristotle's methods of philosophy were the best means by which to understand God and prove God's existence-- though Aristotle had denied the existence of a creator.
In the West, great scholars of the Christian Church arose. These philosophers, people such as Augustine (354-430), Albertus Magnus (ca. 1206-1280), Roger Bacon (ca. 1214-1294), and Thomas Aquinas (1225-74), made Plato and Aristotle fit into Christian philosophy, a molding process that gave Christian Catholicism a rich intellectual heritage it still possesses today.
In all three Western and Middle Eastern cultures, competing mystical strains of semi-philosophical, semi-religious, and semi-spiritualist schools of thought also arose during the Medieval Ages. In Islam, Sufism developed. In Judaism, interest in the mystical Kabalah grew.
And in the West, alchemy--an occult and spiritual art that only incidentally was related to chemistry--developed. All three schools of thought, though mysterious and requiring special knowledge of some kind for participation, counted among themselves some of their cultures' most important religious and political leaders.
In India, China, and Japan, philosopher-scholars were at work, too. In India, Vedanta--from older Hindu scriptures--came to dominate while Buddhism and Jainism declined.

The philosopher Ramanuja (12th cent.) and others who followed him gave India the Vedanta movement that emphasized the existence of one primary Being or God.
In China, Buddhism briefly found more fertile ground, and two forms of it developed: T'ien-T'ai, and Meditation--known better by its Japanese name of "Zen" Buddhism.
These two forms of Chinese Buddhism co-existed with popular Taoist and Confucian religions until Confucianism--the religion of the upper classes--slowly absorbed the other religions into itself.
Confucianism developed three strains: the Schools of Principle (Reason), Mind (Idealism), and Practical Learning (Empiricism). These three schools were most powerfully developed in the philosophies of, respectively, Chu Hsi (1130-1200), Wang Yang-ming (1472--1529), and Tai Chen (1724- 77).

In Japan, Zen Buddhism and Confucianism overshadowed the native religion called Shinto. The Japanese teacher Kukai (Kobo Daishi), 774-835, brought all three religions together in a philosophical and religious system that made Buddhism dominant.