Meditation on any theme, if positive and honest, inevitably separates him who does the meditating from the opinion prevailing around him, from that which … can be called “public” or “popular” opinion. What is Philosophy? 

I have always thought that clarity is a form of courtesy that the philosopher owes; moreover, this discipline of ours considers it more truly a matter of honor today than ever before to be open to all minds … This is different from the individual sciences which increasingly [interpose] between the treasure of their discoveries and the curiosity of the profane the tremendous dragon of their closed terminology. History as a System

Books are the training weights of the mind. The Art of Living

"When we see men of a contrary character, we should turn inwards and examine ourselves." The Analects of Confucius