
Samuel Taylor Coleridge.    
  To write or talk concerning any subject, without having previously taken the pains to understand it, is a breach of the duty which we owe to ourselves, though it may be no offence against the laws of the land. The privilege of talking and even publishing nonsense is necessary in a free state; but the more sparingly we make use of it the better.
Samuel Taylor Coleridge.    
  Rude and unpolished are all the operations of the soul in their beginnings, before they are cultivated with art and study.
John Dryden.    
  Did we but compare the miserable scantness of our capacities with the vast profundity of things, truth and modesty would teach us wary language.
Joseph Glanvill.    
  I respect the man who knows distinctly what he wishes. The greater part of all the mischief in the world arises from the fact that men do not sufficiently understand their own aims. They have undertaken to build a tower, and spend no more labour on the foundation than would be necessary to erect a hut.  5
  Ignorance gives a sort of eternity to prejudice, and perpetuity to error.
Robert Hall: Advantages of Knowledge to the Lower Classes.    
  Obstinate contemners of all helps and arts, such as, presuming on their natural parts, dare deride all diligence, and seem to mock at the terms when they understand not the things, think that way to get off wittily with their ignorance.
Ben Jonson.    
  Things reflected on in gross and transiently carry the show of nothing but difficulty in them, and are thought to be wrapt up in impenetrable obscurity.
John Locke.    
John Locke.    
John Locke.    
  There never was any party, faction, sect, or cabal whatsoever, in which the most ignorant were not the most violent: for a bee is not a busier animal than a blockhead. However, such instruments are necessary to politicians; and perhaps it may be with states as with clocks, which must have some lead weight hanging at them, to help and regulate the motion of the finer and more useful parts.
Alexander Pope.    
  Few consider into what degree of sottishness and confirmed ignorance men may sink themselves.
Robert South.    
  It is impossible to make people understand their ignorance, for it requires knowledge to perceive it; and therefore he that can perceive it, hath it not.
Jeremy Taylor.    
  When complaints are made—often not altogether without reason—of the prevailing ignorance of facts on such or such subjects, it will often be found that the parties censured, though possessing less knowledge than is desirable, yet possess more than they know what to do with. Their deficiency in arranging and applying their knowledge, in combining facts, and correctly deducing, and rightly employing, general principles, will be perhaps greater than their ignorance of facts.
Richard Whately: Pref. to Bacon’s Essays.    
