人口論
In addition to Adam Smith's legacy, Say's law, Malthus theories of population and Ricardo's iron law of wages became central doctrines of classical economics. Jean Baptiste Say challenged Smith's labour theory of value, believing that prices were determined by utility and also emphasised the critical role of the entrepreneur in the economy. However, neither of those observations became accepted by British economists at the time. Thomas Malthus wrote "An Essay on the Principle of Population" in 1798, becoming a major influence on classical liberalism.