On Erroneous Views and Sanity

However, it is clear that if the mere fact that a man shares erroneous views and acts according to his errors qualifies him as mentally disabled, it would be very hard to discover an individual to which the epithet sane or normal could be attributed. Then we are bound to call the past generations lunatic because their ideas about the problems of the natural sciences and concomitantly their techniques differed from ours. Coming generations will call us lunatics for the same reason. Man is liable to error. If to err were the characteristic feature of mental disability, then everybody should be called mentally disabled.

Source: Ludwig Von Mises, Human Action, Chapter 9, Section 2, The Role of Ideas: World View and Ideology, 1949