Qualms On Foreign Trade

"7.5. The idea that the opening of foreign trade bears a close resemblance to technical progress, in that in both cases additional processes of production are made available to the economy, is clearly expressed in Ricardo's Principles in the chapter 'On Foreign Trade'... Ricardo in fact compares the extension of trade to improvements in machinery, and, taking the real wage rate as given, investigates whether trade or improved machinery will have an impact on the general rate of profit. He concludes that if 'by the extension of foreign trade, or by improvements in machinery, the food and necessaries of the labourer can be brought to market at a reduced price, profits will rise,' whereas 'if the commodities obtained at a cheaper rate... be exclusively the commodities consumed by the rich, no alteration will take place in the rate of profits'...

7.6. In recent years the pure theory of trade has been reformulated, using a 'classical' approach to the theory of value and distribution and paying special attention to the fact that capital consists of produced means of production. A start was made by Parrinello (1970), followed by several contributions by Steedman, Metcalfe and Steedman, and Mainwaring... It was shown that several of the traditional trade theorems, derived within the Heckscher-Ohlin-Samuelson model, do not carry over to a framework with a positive rate of profit (interest) and produced inputs (capital goods). (As is well known, the Heckscher-Ohlin-Samuelson model of international trade assumes two countries producing the same two commodities by means of the same constant returns to scale technology, using the same two primary inputs, each of which is taken to be homogeneous across countries.) With a positive rate of interest that is uniform across countries some, though not all, of the standard theorems are undermined (including the 'factor price equalization theorem'), while with different rates of interest in different countries all standard theorems except the Rybczynski theorem turn out to be untenable. The 'gains' from trade for the single small open economy need not be positive. When in the Heckscher-Ohlin-Samuelson theory one of the two primary factors (land) is replaced by a factor called 'capital', the 'quantity' of which is represented in terms of a given total value of capital, then the theory is deprived of its logical coherence..." -- Heinz D. Kurz and Neri Salvadori, Theory of Production: A Long-Period Analysis, Cambridge University Press, 1995.

P.S. Some mainstream economists have recently expressed doubts about the empirical ability of the theory of comparative advantage and its use as a basis for policy. One can add Paul Krugman to the doubters.