Office and intellectual training
The Shiji's autobiographical postface says that Sima Tan studied celestial matters with Tang Du, the Changes with Yang He, and Daoist arguments with Huangzi. He held the office of grand historian during Emperor Wu's reign. Astronomical and calendrical learning stood alongside discussion of political order within his intellectual formation.
The postface distinguishes responsibility for celestial matters from governing the population. Grand historian was an imperial office, not simply an equivalent of the modern occupation of historical author. Sima Tan's duties and learning accompanied an interest in organizing accounts of past and contemporary affairs. The Hanshu later situated this background within the careers of father and son.
A survey of six intellectual traditions
The postface preserves Sima Tan's assessment of yin-yang, Confucian, Mohist, names, legalist and Daoist traditions. He compares advantages and limitations, examining matters such as ritual order, economy of resources, names and realities, and relations between ruler and ministers. His judgments identify useful elements while criticizing rigidity.
He particularly commends a Daoist capacity to adapt to circumstances and incorporate useful insights from other traditions. The survey brings different approaches to politics, society and cultivation into a comparative framework. Its sixfold classification is Sima Tan's analytical arrangement, rather than evidence that all earlier writers identified themselves through those six labels.
References: [1]
The historical project and its textual record
When Emperor Wu performed the feng and shan ceremonies in 110 BCE, Sima Tan was unable to accompany him and subsequently became gravely ill. The postface describes him holding his son's hand and urging him to continue historical work, preserve accounts of people and accomplishments, and fulfill the responsibilities associated with their office.
Sima Qian later succeeded to the office, gained access to imperial records and continued the project. The Shiji's annals, tables, treatises, hereditary houses and biographies resulted from further sustained work. Sima Tan's ambitions and instruction are known through the son's account and its later transmission in the Hanshu; the deathbed dialogue forms part of that authorial self-presentation.