Back to classic theosophy quotes

Friends and foes! Criticism is the sole salvation from intellectual stagnation. It is the beneficent goad which stimulates to life and action - hence to healthy changes - the heavy ruminants called Routine and Prejudice, in private as in social life. Adverse opinions are like conflicting winds which brush from the quiet surface of a lake the green scum that tends to settle upon still waters. If every clear stream of independent thought, which runs through the field of life outside the old grooves traced by Public Opinion, had to be arrested and to come to a standstill, the results would prove very sad. The streams would no longer feed the common pond called Society, and its waters would become still more stagnant than they are. Result: it is the most orthodox "authorities" of the social pond who would be the first to get sucked down still deeper into its ooze and slime.

H.P. blavatsky Col. Wr. Vol. XIII, p. 244
More on this subject