About Tan Sima, 司馬談
Sima Tan (Chinese: 司馬談; Wade–Giles: Ssu-ma T'an, c. 165 BC – 110 BC) was an early Chinese historian who worked under the Western Han. He studied astronomy with Tang Du, the I Ching under Yang He and Daoism under Master Huang. He held the position of Grand Historian between 140-110 BC. While Sima Tan had begun the Records of the Grand Historian (Shiji), he died before it was finished. It was left to his son, Sima Qian, to complete.
An essay by him has survived within the Records of the Grand Historian. In this essay, Sima Tan speaks of six philosophical lineages or "schools" (jia): Confucianism (ru jia), Daoism (dao jia), Legalism (fa jia), Mohism (mo jia), School of Names (ming jia), and Naturalism (yin yang jia)--the central figure of this last "school" being Tsou Yen. This organization of the philosophers of the past into six schools was somewhat original. As for his assessment of these schools, it is rather biased towards Daoism as Sima Tan was a follower of Huang Lao, an early Han form of Daoism.