Certainty

The compulsive quest for certainty is not the expression of genuine faith but is rooted in the need to conquer the unbearable doubt.

— Erich Fromm, Escape from Freedom

The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.

— Bertrand Russell, philosopher, mathematician, author, Nobel laureate (1872-1970)