The proverb ‘A little knowledge is a dangerous thing’ expresses the idea that a small amount of knowledge can mislead people into thinking that they are more expert than they really are, which can lead to mistakes being made.

‘A little knowledge is a dangerous thing’ and ‘a little learning is a dangerous thing’ have been used synonymously since the 18th century.

Alexander Pope – A little knowledge is a dangerous thingThe ‘little learning’ version is widely attributed to Alexander Pope (1688 – 1744). It is found in his An Essay on Criticism, 1709 and I can find no earlier example of the expression in print:

A little learning is a dangerous thing;
drink deep, or taste not the Pierian spring:
there shallow draughts intoxicate the brain,
and drinking largely sobers us again.