Should-Read: Thomas Robert Malthus: Principles of Political Economy Considered with a View to Their Practical Application: “We cannot too highly respect and venerate that admirable rule of Newton, not to admit more causes than are necessary… but the rule itself implies, that those which really are necessary must be admitted…

…Before the shrine of truth, as discovered by facts and experience, the fairest theories and the most beautiful classifications must fall. The chemist of thirty years ago may be allowed to regret, that new discoveries in the science should disturb and confound his previous systems and arrangements; but he is not entitled to the rank of philosopher, if he does not give them up without a struggle, as soon as the experiments which refute them are fully established…. There are many important propositions in political economy which absolutely require limitations and exceptions…. The frequent combination of complicated causes, the action and reaction of cause and effect on each other, and the necessity of limitations and exceptions in a considerable number of important propositions, form the main difficulties of the science, and occasion those frequent mistakes which it must be allowed are made in the prediction of results.

To explain myself by an instance. Adam Smith has stated, that capitals are increased by parsimony, that every frugal man is a public benefactor, and that the increase of wealth depends upon the balance of produce above consumption. That these propositions are true to a great extent is perfectly unquestionable. No considerable and continued increase of wealth could possibly take place without that degree of frugality which occasions, annually, the conversion of some revenue into capital, and creates a balance of produce above consumption; but it is quite obvious that they are not true to an indefinite extent, and that the principle of saving, pushed to excess, would destroy the motive to production.

If every person were satisfied with the simplest food, the poorest clothing, and the meanest houses, it is certain that no other sort of food, clothing, and lodging would be in existence; and as there would be no adequate motive to the proprietors of land to cultivate well, not only the wealth derived from conveniences and luxuries would be quite at an end, but if the same divisions of land continued, the production of food would be prematurely checked, and population would come to a stand long before the soil had been well cultivated. If consumption exceed production, the capital of the country must be diminished, and its wealth must be gradually destroyed from its want of power to produce; if production be in a great excess above consumption, the motive to accumulate and produce must cease from the want of an effectual demand in those who have the principal means of purchasing.

The two extremes are obvious; and it follows that there must be some intermediate point, though the resources of political economy may not be able to ascertain it, where, taking into consideration both the power to produce and the will to consume, the encouragement to the increase of wealth is the greatest…