Who is Wei Mou 魏牟？ What is his famous "White Horse Not Horse" theory?

Wei Mou（魏牟）, a Daoist philosopher during the Warring States Period, was also known as Lord Mou of Zhongshan and was a native of the State of Wei. His main activities spanned approximately 295–256 BCE. He was on friendly terms with Gongsun Long and firmly believed in his doctrines. When others harshly criticized Gongsun Long and his theories, he strongly defended him, stating: *"Without subjective intention, minds align; without specific reference, all concepts converge. Those who fully grasp the nature of things always exist. The shadow does not move—because it changes continuously. A single hair can suspend a thousand jun [a unit of weight]—when forces are perfectly balanced. A white horse is not a horse—because form and name are distinct. An orphaned calf has never had a mother—for having a mother would make it no longer an orphan."* (from *Liezi · Zhongni Pian*). From the perspective that form and name are separate, he upheld Gongsun Long’s thesis of *"a white horse is not a horse."*  

Admiring Zhuangzi, he leaned toward Daoist philosophy in his view of life, regarding Zhuangzi’s ideas as broad and profound, and Zhuangzi’s words as *"extremely subtle."* He stated, *"A thousand li [a unit of distance] is insufficient to describe its vastness; a thousand ren [a unit of height] is insufficient to fathom its depth."* (from *Zhuangzi · Qiushui Pian*).  

He elaborated on Laozi’s view that *"wealth, honor, and arrogance bring one’s own downfall,"* arguing that wealth and honor naturally lead to fine food, fine food leads to arrogance and extravagance, and arrogance and extravagance inevitably invite disaster and ruin. He said: *"Nobility does not seek wealth, yet wealth arrives; wealth does not seek fine food, yet fine food arrives; fine food does not seek arrogance, yet arrogance arrives; arrogance does not seek death, yet death arrives. Throughout history, many have perished due to this."* (from *Strategies of the Warring States · Zhao Ce San*). Influenced by Daoist philosophy, he practically adopted a passive, world-avoiding attitude: *"He preferred to associate with virtuous scholars and neglect state affairs"* (from *Liezi · Zhongni Pian*), and eventually *"retired to a mountain cave"* (from *Zhuangzi · Rang Wang Pian*). However, he did not entirely disregard worldly affairs, as he was described as *"physically dwelling by rivers and seas, yet mentally focused on the royal court"* (from *Lüshi Chunqiu · Shenwei*). *Xunzi · Feishierzi* criticized him for *"indulging in emotions and behaving recklessly,"* while Han Ying of the Han Dynasty stated that Wei Mou’s ideas and actions *"were insufficient to align with the Grand Dao, improve customs, or govern order, but were enough to deceive and mislead the ignorant."* (from *Han Shi Waizhuan*, Volume 4, Chapter 22).  

Regarding Wei Mou’s identity, one theory claims Lord Mou was a son of Marquis Wen of Wei: *"When Wei conquered Zhongshan, it enfeoffed the territory to Lord Mou, hence the name Lord Mou of Zhongshan."* (Zhang Zhan’s annotation in *Liezi · Zhongni Pian*). According to Sun Yirang’s textual research, this is incorrect. The Zhongshan State of the Xianyu people was initially conquered by Wei; in the 17th year of Marquis Wen’s reign (430 BCE), General Yue Yang besieged Zhongshan and destroyed it three years later, enfeoffing the territory to his son Ji. Later, Ji became crown prince, and the territory was re-enfeoffed to Marquis Wen’s second son, Zhi. After Zhongshan was later restored as a state, it was conquered by Zhao in the 4th year of King Huiwen of Zhao’s reign (295 BCE), as recorded in the *Records of the Grand Historian* in the genealogical histories of Wei and Zhao, as well as the "Biography of Yue Yi." Texts such as *Liezi · Zhongni Pian*, *Zhuangzi · Rang Wang Pian*, *Lüshi Chunqiu · Shenwei Pian*, and *Huainanzi · Daoying Xun* all refer to him as Lord Mou of Wei-Zhongshan. Commentators Gao You and Zhang Zhan claimed that Wei enfeoffed Zhongshan to Lord Mou, but by Wei Mou’s time, Zhongshan had long been annexed by Zhao. How could it still belong to Wei? Thus, it is beyond doubt that the Zhongshan he was enfeoffed with was not the Xianyu Zhongshan. Zhang Zhan’s claim that Lord Mou was a son of Marquis Wen of Wei likely conflates him with Zhi, making this theory even more erroneous. (Quoted from Yang Bojun’s *Collected Annotations on Liezi*, pp. 137–138). The *Hanshu · Yiwenzhi* (Book of Han · Treatise on Literature) lists four chapters of *Gongzi Mou* under Daoist works, which are now lost.