Jiē Xuān 揭暄 (zì Zǐxuān 子宣 and Wěishū 緯叔; 1613–1695; native of Guǎngchāng 廣昌 in Jiāngxī) was a late-Míng / early-Qīng natural philosopher, mathematician and military strategist who refused to serve the Qīng after 1644 and devoted his retirement to the synthetic study of cosmology, astronomy and Western (Jesuit-introduced) natural philosophy. He was the close intellectual associate of Fāng Yǐzhì 方以智 (whose son Fāng Zhōngtōng 方中通 incorporated Jiē’s astronomical position into his Shùdù yǎn 數度衍). Author of the Xuánjī yíshù 璇璣遺述 (KR3fa029) on cosmology and stellar mechanics, in 9 juǎn; the Bīngjīng 兵經 (a treatise on military strategy, widely consulted in the late-Qīng); and other works. Jiē anticipated several positions later associated with Jesuit-introduced natural philosophy independently of direct Jesuit teaching — most famously a vortex / spiral-motion theory of celestial mechanics in Xuánjī yíshù that some commentators have compared (with caveats) to Descartes’s vortex cosmology. CBDB id 438183, no dates recorded; lifedates 1613–1695 follow the modern consensus established by Shi Yunli 石雲里 and others.