The philosopher's inner life is an isolated one. It would be very foolish to blurt out all that he believes, thinks, or knows in any and every company. He recognizes the graded character of human mentality. This recognition compels him quite often to listen without dispute and with all tolerance to statements embodying extremely limited conceptions, half-developed ideas, or wholly biased views. A consequence of this attitude is that he usually understands more than anyone guesses.
-- Notebooks Category 20: What Is Philosophy? > Chapter 5: The Philosopher > # 156