Concepts which have proved useful for ordering things easily assume so great an authority over us, that we forget their terrestrial origin and accept them as unalterable facts. They then become labeled as 'conceptual necessities,' etc. The road of scientific progress is frequently blocked for long periods by such errors.
Therefore: In dwelling, choose modest quarters, in thinking, value stillness, in dealing with others, be kind, in choosing words, be sincere, in leading, be just, in working, be competent, in acting, choose the correct timing. Follow these words and there will be no error.
In a bull market, one must avoid the error of the preening duck that quacks boastfully after a torrential rainstorm, thinking that its paddling skills have caused it to rise in the world. A right-thinking duck would instead compare its position after the downpour to that of the other ducks on the pond.
The cure of the part should not be attempted without treatment of the whole. No attempt should be made to cure the body without the soul. Let no one persuade you to cure the head until he has first given you his soul to be cured, for this is the great error of our day, that physicians first separate the soul from the body.
For knowing is spoken of in three ways: it may be either universal knowledge or knowledge proper to the matter in hand or actualising such knowledge; consequently three kinds of error also are possible.