There are four chief obstacles in grasping truth … namely, submission to faulty and unworthy authority, influence of custom, popular prejudice, and the concealment of our own ignorance accompanied by an ostentatious display of our knowledge.

Roger Bacon (c.1220–1292) English philosopher and scientist

Opus Majus, Vol 1, “The Causes of Error” (c. 1270 (pub. 1733))

Alt trans: "There are in fact four very different stumbling blocks in the way of grasping the truth, which hinder every man however learned, and scarcely allow anyone to win a clear title to wisdom, namely, the example of weak and unworthy authority, longstanding custom, the feeling of the ignorant crowd, and the hiding of our own ignorance while making a display of our apparent knowledge."