The Collected Essays of Arthur Schopenhauer (Unexpurgated Edition) (Halcyon Classics)

Subsequently, all the opinions that have sprung from misapplied ideas have to be rectified by a lengthy experience; and it is seldom that they are completely rectified. This is why so few men of learning have such sound common sense as is quite common among the illiterate.

People know, or dimly feel, that if thinking is not kept pure and keen, and if respect for the world of the mind is no longer operative, ships and automobiles will soon cease to run right, the engineer’s slide rule and the computations of banks and stock exchanges will forfeit validity and authority, and chaos will ensue.