Knowledge without practice is useless. Practice without knowledge is dangerous.
To lead uninstructed people to war is to throw them away.
Learning without thought is labor lost; thought without learning is perilous.
What is necessary is to rectify names.
The superior man honors his virtuous nature, and maintains constant inquiry and study, seeking to carry it out to its breadth and greatness, so as to omit none of the more exquisite and minute points which it embraces, and to raise it to its greatest height and brilliancy.
The book salesman should be honored because he brings to our attention, as a rule, the very books we need most and neglect most.