Intelligence; not because you think you know everything without questioning, but rather because you question everything you think you know.

“A wise man makes his own decisions, an ignorant man follows public opinion” 
Chinese Proverb

“The one who follows the crowd will usually go no further than the crowd. The one who walks alone is likely to find himself in places no one has ever been before.” 
Albert Einstein

Also watch an enlightening video from an interesting website (