Huán Tán 桓譚 (c. 23 BCE – c. 56 CE), zì Jūnshān 君山. Native of Pèiguó Xiāng 沛國相 (modern Sùzhōu 宿州, Ānhuī). Held office as láng under Chéngdì 成帝 (r. 33–7 BCE), Āidì 哀帝, and Píngdì 平帝; Zhǎngyuè dàfū (Grand Master of Court Music) under Wáng Mǎng 王莽 (r. 9–23 CE); after the Eastern-Hàn restoration, Yìláng 議郎 under Guāngwǔdì 光武帝 (r. 25–57 CE).
One of the leading rationalist and historical-critical thinkers of the Western-Hàn / Eastern-Hàn transition. His refusal to confirm the chènwěi (prognostication-apocrypha) predictions in front of Guāngwǔdì — the famous incident recorded in the HòuHàn shū biography (juàn 28) — led to his demotion to Liùān chéng; he died of distress on the road.
His principal work, the Xīn lùn 新論 (KR3j0192) in 17 juàn, is preserved only in fragments. His other surviving compositions include the Wàng xiān fù 望仙賦 (Daoist immortality satire) and various memorials. Huán’s articulation of the body-flame / spirit-wax analogy in the xíngshén (body-spirit) debate is the foundational Chinese statement of the materialist position, taken up by Wáng Chōng 王充 in the Lùn héng and developed by Fàn Zhěn 范縝 in the 5th–6th c.
Treated in Timoteus Pokora, Hsin-lun (New Treatise) and Other Writings by Huan T’an, Michigan, 1975 — the definitive English-language fragment-translation and biographical study.