Ricardo's Volte-Face on Machinery
重新表述了李嘉图用来解释他改变对技术影响劳动看法的数值例子，指出其分析困难源于缺乏明确的需求理论，导致结果不明确。
A formal restatement of the numerical example Ricardo invoked to explain his change of mind on the feasibility of the depressing effect of technology on labor underlines the analytical difficulty that he could not overcome and thus explains his inconclusive results. This difficulty is basically due to the absence of a clearly perceived demand theory--demands for goods, factor services, and money--characteristic of him and of classical economics in general. Since the focus of the technology labor issue is on the expected change of demand for labor in response to technical change, the failure of classical economists and of Ricardo to propose a relevant theory was inevitable.