He was now “convinced that the substitution of machines for human labor is often very injurious to the class of laborers,” that the “same cause which may increase the net revenue of the country, may at the same time render the population redundant.” As a result, “the opinion entertained by the laboring class, that the employment of machinery is frequently detrimental to their interests, is not founded on prejudice and error, but is conformable to the correct principles of political economy.”
这就是十九世纪最有影响力的经济学家大卫·李嘉图的最初看法。但在其《政治经济学》第三版（1817年）中，他加入了一章关于机器的内容，改变了看法。他“认为机器取代人力劳动往往会给劳动阶级造成伤害”，“在国家净收入获得提高的同时，可能造成人口过剩。”因此，“劳动阶级所持有的观点，即机器的使用往往不利于他们的利益，并不是建立在偏见和错误的基础之上，反而十分符合政治经济学的正确原理。”