The idiom “自以为是” literally means “to consider oneself in the right”, but the real meaning is more pointed: a self-righteous person who believes they are absolutely correct and cannot be corrected by others. It comes from a commentary in the Book of Rites (礼记), which describes a certain type of person in society: They go along with vulgar customs, fit into a corrupt world, appear loyal and honest, behave as if they are upright and incorruptible. Everyone praises them, and they believe themselves to be right. Yet they cannot enter the Way of Yao and Shun. Therefore, they are called the thieves of virtue. The critique here is interesting. The problem isn’t stupidity or incompetence — it’s socially reinforced self-righteousness. This type of person: • fits into the mainstream • gains approval from the crowd • appears moral on the surface • believes they are unquestionably right • and thus becomes unable to be taught or improved In Confucian thought, such people are considered dangerous not because they break social norms, but because they perfectly conform to them while believing themselves morally superior. In modern usage, “自以为是” applies to anyone who refuses criticism, rejects correction, and assumes their opinions are universally valid. It’s less about confidence and more about closed-minded certainty. English equivalents include: • self-righteous • smugly convinced of one’s correctness • “sure they’re right even when they’re wrong” The idiom works well in daily life, politics, and even internet culture — we all know people who act like this. 出处 同乎流俗，合乎污世，居之似忠信，行之似廉洁，众皆悦之，自以为是，而不可与入尧舜之道，故曰德之贼也。 《孟子·尽心下》 典故 据《孟子·尽心下》记载，孟子的弟子万章曾向孟子提出了一个问题：为什么那些被大家公认为是忠厚老实的人，在孔子的眼中却是道德沦丧的贼？孟子回答说：“同乎流俗，合乎污世，居之似忠信，行之似廉洁，众皆悦之，自以为是，而不可与入尧舜之道，故曰德之贼也。” 这句话的意思是：那些随波逐流、迎合世俗的人安于现状，看似忠厚老实，行为廉洁，很受大家的欢迎。但他们的内心并不真正理解尧舜之道，缺乏真正的道德觉悟。他们自认为自己的行为和观点都是正确的，不愿意虚心接受他人的意见。这样的人虽然在表面上看起来有德，但实际上却缺乏真正的道德修养。 成语“自以为是”就从孟子的这段话中演变而来，也作“自以为然”，其中“是”“然”指正确。 引证 凡斗者，必自以为是而以人为非也。己诚是也，人诚非也，则是己君子而人小人也。 《荀子·荣辱》