Note 390 — Chapter V

The two writers who have inquired most carefully into the method which political economists ought to follow, are Mr. John Mill (Essays on Unsettled Questions of Political Economy, 1844, pp. 120–164) and Mr. Rae (New Principles of Political Economy, 1834, pp. 328–351). Mr. Rae, in his ingenious work, objects to Adam Smith that he transgressed the rules of the Baconian philosophy, and thus prevented his inferences from being as valuable as they would have been if he had treated his subject inductively. But Mr. Mill, with great force of reasoning, has proved that the deductive plan is the only one by which political economy can be raised to a science. He says, p. 143, political economy is ‘essentially an abstract science, and its method is the method a priori;’ and at p. 146, that the a posteriori method is ‘altogether inefficacious.’ To this I may add, that the modern theory of rent, which is now the corner-stone of political economy, was got at, not by generalizing economical facts, but by reasoning downwards after the manner of geometricians. Indeed, those who oppose the theory of rent, always do so on the ground that it is contradicted by facts; and then, with complete ignorance of the philosophy of method, they infer that therefore the theory is wrong. See, for instance, Jones on the Distribution of Wealth, 8vo. 1831: a book containing some interesting facts, but vitiated by this capital defect of method. See also Journal of Statistical Society, vol. i. p. 317, vol. vi. p. 322; where it is said that economical theories should be generalized from statistical facts. Compare vol. xvii. p. 116, vol. xviii. p. 101.