Malthus to Solow

摘要

Until very recently, the literature on economic growth focused on explaining features of modern industrial economies while being inconsistent with the growth facts describing pre-industrial economies. This includes both models based on exogenous technical progress, such as Robert M. Solow (1957), and more recent models with endogenous growth, such as Paul M. Romer (1986) and Lucas (1988). But sustained growth has existed for at most the past two centuries, while the millennia prior have been characterized by stagnation with no significant permanent growth in living standards. This paper contributes to a recent literature describing unified growth models that can account for the basic growth facts of both eras, as well as the transition between the two. In particular, our theory predicts that land's share in production should fall endogenously over time, as observed historically, and that there will be an escape from Malthusian stagnation and a transition to modern growth in the sense of Solow. Some caveats are in order. Although it has become popular in the growth literature to model the accumulation of nonrivalrous knowledge as an endogenous feature of the model economy studied, we have chosen to abstract from this and assume exogenous technological progress. We made this choice both because it simplifies our analysis and because we do not believe that there yet exists a theory of knowledge accumulation with the same level of acceptance that is accorded to the standard theory of capital accumulation. For those who disagree, we believe that endogenous growth features can be easily incorporated into our theory in a way that does not alter our main findings. In addition, we have not explored how policy and institutions, by discouraging or preventing the invention and adoption of new ideas, might play an important role in determining when the Solow technology is first used and how quickly the transition from Malthus to Solow is completed. Jones (1999), for example, emphasizes the role that policy and institutions, by affecting the rate of compensation for inventive activity, might play in determining the timing of the industrial revolution. In addition, Stephen L. Parente and Prescott (1997) have studied how policy can affect the level of the total factor productivity parameter in the Solow technology. By keeping this parameter small, policy can affect when equation (8) is satisfied and, hence, when (if ever) the industrial revolution begins. The fact that the industrial revolution happened first in England in the early 19th century rather than contemporaneously or ear- lier in China, where the stock of usable knowledge may have actually been higher, is perhaps due to the institutions and policies in place in these two countries. )