Ji Xianlin, a famous paleographer , historian, and writer, was born in 1911. In 1930, Ji was admitted to Tsinghua University as a major in Western literature. In 1935, he went to Germany as an exchange student to study ancient languages, receiving his PhD degree in 1941.  Ji returned to China in 1946, and in the autumn of the same year, became a professor in Peking University. Ji Xianlin believes, "Cultural exchange is the main drive for humankind's progress. Only by learning from each other's strong points to make up for shortcomings can people constantly progress, the ultimate  _ of which is to achieve a kind of Great Harmony. " Over the past ten years, Ji has actively participated in discussions on the cultural problems between the East and the West, based on the same ideology. According to him, human culture is divided into four parts: Chinese culture, Indian culture, Arabic-Islamic culture and European-American culture,  with the former three making up the Eastern cultural system and the last the Western one. With his achievements in the history of Sino-Indian cultural relations, Buddhism history,  Indian literature, and comparative literature, Ji Xianlin is known as a master of Eastern studies both at home and abroad. What is the main idea of the passage?
The brief introduction of Ji Xianlin. Ji Xianlin's ideology. Ji Xianlin's achievements. Ji Xianlin's discussions on the cultural problems between the East and the West.