"Natural" and "Improved" Land in Marx's Theory of Rent
探讨马克思价值理论中自然产物与人类劳动产物在土地租金计算中的关系，分析如何区分土地的自然属性与改良属性对产出价值的贡献。
Marxian value theory has always had some difficulty with incorporating the products of nature into the calculation of value. Right at the start of Capital, Marx ([1894] 1976) insists that it is not the purpose of his theory to explain the contribution of all phenomena to the value of output. This may be satisfactory as a general proposition of the objectives of Marxian value analysis, but it faces difficulty in the understanding of ground rent, for here the relationship between natural and (human) phenomena must be addressed directly. It is not sufficient to isolate nature as outside the value sphere. Specifically, the question must be posed: how, within Marxist theory, do we understand the relationship between and produced attributes of land; for example, how do we compare the contribution of a man-made dam and a naturally occurring dam to the value of output produced on land?