S. Austin Allibone, comp. Prose Quotations from Socrates to Macaulay. 1880.
Some are so close and reserved as they will not shew their wares but by a dark light, and seem always to keep back somewhat; and when they know within themselves they speak of that they do not well know, would nevertheless seem to others to know of that which they may not well speak.
A man who knows the world will not only make the most of everything he does know, but of many things he does not know; and will gain more credit by his adroit mode of hiding his ignorance than the pedant by his awkward attempt to exhibit his erudition.
It is worth noticing, that those who assume an imposing demeanour, and seek to puff themselves off for something beyond what they are (and often succeed), are not unfrequently as much under-rated by some as they are over-rated by others. For, as a man (according to what Bacon says in the essay On Discourse) by keeping back some knowledge which he is believed to possess may gain credit for knowing something of which he is really ignorant, so if he is once or twice detected in pretending to know what he does not, he is likely to be set down as a mere pretender, and as ignorant of what he does know.
Silver gilt will often pass
Either for gold or else for brass.
Richard Whately: Annot. on Bacons Essay, Of Seeming Wise.