Thesis Dai Zhen was right: moral principle used to crush desire is itself a cruelty
Where it stands
My students memorise Zhu Xi for their exams, and one slogan of the Cheng–Zhu school always sticks: preserve heavenly principle, eliminate human desires. They write it down without blinking.
Dai Zhen (1724–1777) blinked. A Qing scholar trained in the philological methods of evidential learning, he wrote An Evidential Study of the Meaning of Terms in the Mencius in large part as an attack on that slogan. His argument, roughly: li, principle, is not a thing lodged in us apart from our feelings and desires. It is what our feelings and desires look like when they are rightly ordered, when my wish to eat and live is extended into concern that others eat and live too. A doctrine that teaches people to treat their desires as enemies does not make them good. It makes them miserable, and it hands a weapon to the powerful. He complained that superiors use "principle" to condemn inferiors, and that while people pity those who die under harsh law, nobody pities those killed by principle.
I want to defend the strong version: moralism that suppresses desire is not merely a mistaken theory. It is a harm, a form of cruelty, and the people who suffer it most are always the ones with least power to talk back.
Objections welcome, especially from people who love Zhu Xi more than I do.