These ideas about capital and unproductive labour are certainly of great importance in the history of economic theory, but they were fundamentally unsound, and were never so universally accepted as is commonly supposed. The conception of the wealth of nations as an annual produce, annually distributed, however, has been of immense value. Like other conceptions of the kind it was certain to come. It might have been evolved direct from Davenant or Petty nearly a century before. We need not suppose that someone else would not soon have given it its place in English economics if Adam Smith had not done so, but that need not deter us from recording the fact that it was he who introduced it, and that he introduced it in consequence of his association with the Économistes .
If we attempt to carry the history of the origin of the Wealth of Nations farther back than the date of the lecture notes in 1763 or thereabouts, we can still find a small amount of authentic information. We know that Smith must have been using practically the same divisions in his lectures in 1759, since he promises in the last paragraph of the Moral Sentiments published in that year, “another discourse” in which he would “endeavour to give an account of the general principles of law and government, and of the different revolutions they have undergone in the different ages and periods of society, not only in what concerns justice, but in what concerns police, revenue and arms, and whatever else is the object of law.” It seems probable, however, that the economic portion of the lectures was not always headed “police, revenue, and arms,” since Millar, who attended the lectures when they were first delivered in 1751–2, says:—