Treatise on Sitting in Oblivion 坐忘论

Written by Sima Chengzhen, a patriarch of the Shangqing School in the Tang Dynasty, this work was recorded as one volume in both Book of Tang·Bibliography and History of Song·Bibliography, and as three volumes in Comprehensive Records·Bibliography of Literature. The existing version, in one volume, is included in the Taixuan Section of The Daozang.

It is also included in Volume 94 of Yunji Qiqian (Seven Slips of the Cloud Satchel). The book is divided into seven chapters in the first part, in sequence: Respect and Faith, Severing Attachments, Gathering the Mind, Simplifying Matters, True Observation, Peaceful Stability, and Attaining the Dao. At the end of the book, The Pivot and Wings of Sitting Forgetting is appended to summarize its essence.

Treatise on Sitting in Oblivion

Based on Laozi and Zhuangzi’s theories of purity, tranquility, and sitting forgetting, the book absorbs the Buddhist tenet of dual cultivation of samatha-vipasyana (calming and insight) and prajna (wisdom), expounding the philosophical connotations and methods of Taoist mind and spirit cultivation to align with truth and unite with The Dao. Its core purport lies in "no things, no self" and "not arising a single thought".

It states that practitioners must first uphold sincerity, trust, and reverence, sever mundane attachments, gather the mind and depart from external circumstances, not chase after material things or fame, and maintain an empty and peaceful heart—then the Dao will naturally reside within. Secondly, they must simplify matters and practice true observation, realizing that the self and all things are empty, eliminating mental afflictions and physical desires, accepting one’s destiny, and being content with circumstances.

It is claimed that long-term practice of this way can lead to "a body like withered wood, a mind like dead ashes—no sensations, no desires, extreme tranquility and detachment. Being mindless yet thoroughly stable, hence called 'Peaceful Stability'".

The book also states: "Diligently practice an empty mind and the spirit of the valley, and only the Dao will gather. The Dao possesses profound power, gradually transforming the body and spirit; the body follows the Dao to perfection, uniting with the spirit as one—this unity of body and spirit is called a 'divine person'". It further states: "Concentrate the spirit and cherish Qi, practice the Dao without attachment, and unite the spirit with the Dao—this is called attaining the Dao".

Those who attain the Dao have an eternal and unchanging body, transform their essence into spirit, refine the spirit to subtlety, and merge indistinguishably with the Dao. "Dissolve one’s body into all dharmas, blend all dharmas into one’s body, with boundless wisdom and illumination, and a form transcending all limitations. Unify form and emptiness for use, contain creation and transformation to achieve success"—this is the highest realm of cultivating truth and aligning with the Dao.

Concise in language yet profound in meaning, this book is a famous work of Chongxuan (Double Mystery) philosophy in Taoism during the Tang Dynasty, exerting a significant influence on later Taoist cultivation thought.