Simon Newcomb

A common mistake is that the conclusions of the plain unlettered man differ from those of economists in being more immediately founded on observed facts and less on deduction. The truth is that the plain unlettered man is more prone to rely on deduction from unproved hypotheses than the economist is. All classes must equally use deduction, because it is only by this logical process that we form any conclusion about the future effect of any present cause. Drawing the conclusion that rain will follow a certain direction of the wind with certain appearances of the clouds is an act of logical deduction. The main point in which men’s logical methods differ lies in the care with which hypotheses are formed by induction from observed facts, and the readiness of men to test them. Now it is the plain man who is most prone to form hasty generalizations from insufficient facts, to consider the conclusions which he thence deduces as final, and to be blind to all facts which do not tally with his theory.

Simon Newcomb, Principles of Political Economy, 1886, p. 40.