It is accordingly not the aim of this paper to set aside the time-honored classification of factors, or even to formulate an iconoclastic amendment, but rather to indicate how and why this classification has proved inadequate for certain purposes of theory which were not contemplated by the men who elaborated it. To this end a bit of preface may be in place as regards the aims which led to its formulation and the uses which the three-fold classification originally served. * * * * * The economists of the late eighteenth and early nineteenth centuries were believers in a Providential order, or an order of Nature. How they came by this belief need not occupy us here; neither need we raise a question as to whether their conviction of its truth was well or ill grounded. The Providential order or order of Nature is conceived to work in an effective and just way toward the end to which it tends; and in the economic field this objective end is the material welfare of mankind. The science of that time set itself the task of interpreting the facts with which it dealt, in terms of this natural order. The material circumstances which condition men's life fall within the scope of this natural order of the universe, and as members of the universal scheme of things men fall under the constraining guidance of the laws of Nature, who does all things well. As regards their purely theoretical work, the early economists are occupied with bringing the facts of economic life under natural laws conceived somewhat after the manner indicated; and when the facts handled have been fully interpreted in the light of this fundamental postulate the theoretical work of the scientist is felt to have been successfully done.