The short-run effects are for the most part obvious and seldom escape the notice of a naive observer unfamiliar with searching investigations. What started economic studies was precisely the fact that some men of genius began to suspect that the remoter consequences of an event may differ from the immediate effects visible even to the most simple-minded layman. The main achievement of economics was the disclosure of such long-run effects hitherto unnoticed by the unaffected observer and neglected by the statesman. From their startling discoveries the classical economists derived a rule for political practice. The correctness of this inference is incontestable and indisputable.
Action aims at the substitution of a more satisfactory state of affairs for a less satisfactory.
The reproach is nonsensical. Economics has no means of scrutinizing the results of a change in the data other than to start with its immediate consequences and to analyze, step by step, proceeding from the first reaction to the remoter reactions, all the subsequent consequences, until it finally arrives at its ultimate consequences. It is easy to understand why certain individuals, parties and pressure groups are eager to propagate the exclusive sway of the short-run principle. All that economics has to answer to these passionate critics is that every decision should be based on a careful weighing of all its consequences, both those in the short run and those in the long run. It may sometimes be expedient for a man to heat the stove with his furniture.