Ricardo’s Discovery of Comparative Advantage Revisited

In an influential paper entitled “David Ricardo’s Discovery of Comparative Advantage”, which was published in HOPE (Vol. 34, 2002), Roy J. Ruffin attempted to reconstruct the circumstances of Ricardo’s discovery of the law of comparative advantage. Ruffin’s article has inspired a number of further contributions (see, e.g., Aldrich 2004, Maneschi 2004, 2008, Ruffin 2005, Morales-Meoqui 2011) on the precise nature, logical structure, and analytical significance of Ricardo’s formulation of the law of comparative advantage in international trade theory. The present paper shows that Ruffin’s reconstruction of Ricardo’s discovery of the law of comparative advantage, and in particular his interpretation of Ricardo’s letters to Malthus and James Mill of October 1816, encounters a number of serious problems. When the context of Ricardo’s statements is properly taken into account, and the premises and implications of Ruffin’s hypothesis, according to which those statements refer to international prices, are carefully scrutinized, his novel interpretation is seen to lack plausibility. Moreover, it is shown that Ruffin’s contention that modeling assumptions and analytical results of neoclassical trade theory such as “factor price equalization”, the “Lerner symmetry theorem”, or the “Stolper-Samuelson theorem” can be discerned in Ricardo’s chapter “On Foreign Trade” cannot be sustained.