自以為是

From Xunzi (《荀子·榮辱》):

自以為是

1. to consider oneself in the right; to regard oneself as infallible; self-righteous

   • 只有那些主觀地、片面地和表面地看問題的人，跑到一個地方，不問環境的情況，不看事情的全體（事情的歷史和全部現狀），也不觸到事情的本質（事情的性質及此一事情和其它事情的內部聯繫），就自以為是地發號施令起來，這樣的人是沒有不跌交子的。 [MSC, trad.]
     只有那些主观地、片面地和表面地看问题的人，跑到一个地方，不问环境的情况，不看事情的全体（事情的历史和全部现状），也不触到事情的本质（事情的性质及此一事情和其它事情的内部联系），就自以为是地发号施令起来，这样的人是没有不跌交子的。 [MSC, simp.]

     From: 1937, 毛澤東 (Mao Zedong), 《實踐論》 (On Practice), 《毛澤東選集》. English translation based on the Foreign Languages Press edition

     Zhǐyǒu nàxiē zhǔguān de, piànmiàn de hé biǎomiàn de kàn wèntí de rén, pǎo dào yī gè dìfang, bù wèn huánjìng de qíngkuàng, bù kàn shìqing de quántǐ (shìqing de lìshǐ hé quánbù xiànzhuàng), yě bù chù dào shìqing de běnzhì (shìqing de xìngzhì jí cǐ yī shìqing hé qítā shìqing de nèibù liánxì), jiù zìyǐwéishì de fāhàoshīlìng qilai, zhèyàng de rén shì méiyǒu bù diē jiāozi de. [Pinyin]

     Only those who are subjective, one-sided and superficial in their approach to problems will smugly issue orders or directives the moment they arrive on the scene, without considering the circumstances, without viewing things in their totality (their history and their present state as a whole) and without getting to the essence of things (their nature and the internal relations between one thing and another). Such people are bound to trip and fall.