Eastern philosophy
The "Dao De Jing" ("Tao-Te-Ching," c. 4th century BCE), traditionally attributed to Laozi, and the "Nan Hua Jing" ("Zhuang Zi") are considered the key texts of the tradition. The first organized form of Taoism, the Tianshi (Celestial Masters') school arose in the 2nd century CE. Xuanxue ("deep learning", also "Neo-Taoism") was a major philosophical movement influenced by Confucian scholarship, which focused on the interpretation of the "Yijing," "Daodejing," and "Zhuangzi" and which flourished during the third to sixth centuries CE. The most important philosophers of this movement were He Yan, Wang Bi, the Seven Sages of the Bamboo Grove, Ge Hong and Guo Xiang. Thinkers like He Yan and Wang Bi focused on the deep nature of Tao, which they saw as being best exemplified by the term "Wu" (nothingness, non-being, negativity).
Middle Eastern philosophy
The teachings of Zarathustra (Zoroaster) appeared in Persia at some point during the period 1700-1800 BCE. His wisdom became the basis of the religion Zoroastrianism, and generally influenced the development of the Iranian branch of Indo-Iranian philosophy. Zarathustra was the first who treated the problem of evil in philosophical terms. He is also believed to be one of the oldest monotheists in the history of religion. He espoused an ethical philosophy based on the primacy of "good thoughts (pendar-e-nik), good words (goftar-e-nik), and good deeds (kerdar-e-nik)."