Economics is haunted by more fallacies than any other study known to man. This is no accident. The inherent diﬃculties of the subject would be great enough in any case, but they are multiplied a thousand fold by a factor that is insigniﬁcant in, say, physics, mathematics or medicine – the special pleading of selfish interests. (…). While certain public policies would in the long run beneﬁt everybody, other policies would beneﬁt one group only at the expense of all other groups. In addition to these endless pleadings of self-interest, there is a second main factor that spawns new economic fallacies every day. This is the persistent tendency of men to see only the immediate effects of a given policy, or its effects only on a special group, and to neglect to inquire what the long-run effects of that policy will be not only on that special group but on all groups. It is the fallacy of overlooking secondary consequences.