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."