Writers upon Political Economy have brought much metaphysical acumen to bear upon definitions of Capital, and have reached very widely divergent conclusions as to what the term ought to mean, ignoring the clear and fairly consistent meaning the term actually possesses in the business world around them. The business world has indeed two views of Capital, but they are consistent with one another. Abstractly, money or the control of money, sometimes called credit, is Capital. Concretely, capital consists of all forms of marketable matter which embody labour. Land or nature is excluded except for improvements: human powers are excluded as not being matter; commodities in the hands of consumers are excluded because they are no longer marketable. Thus the actual concrete forms of capital are the raw materials of production, including the finished stage of shop goods; and the plant and implements used in the several processes of industry, including the monetary implements of exchange. Concrete business capital is composed of these and of nothing but these.[1] In taking modern industrial phenomena as the subject of scientific inquiry it is better to accept such terminology as is generally and consistently received by business men, than either to invent new terms or to give a private significance to some accepted term which shall be different from that given by other scientific students, and, if we may judge from past experience, probably inferior in logical exactitude to the current meaning in the business world. § 3. The chief material factor in the evolution of Capitalism is machinery. The growing quantity and complexity of machinery applied to purposes of manufacture and conveyance, and to the extractive industries, is the great special fact in the narrative of the expansion of modern industry.