Inside the black box of population growth : tracing the roots of unified growth theory

This article traces the roots of Unified Growth Theory, a strand of growth theory that aims at explaining the patterns of economic development over the very long-run, in various attempts to open the black box into which population growth was initially put. Doing so tells a story of longstanding efforts to unify theories of stagnation and sustained growth, the distinct object of study of two fields that parted ways in the mid 20th century, development economics and growth theory, by building a theory of the entire process of development in which population dynamics plays a central role. Unified growth models have become an integral part of growth theory alongside endogenous growth models, and their respective trajectories share similarities, as the treatment of population growth as a black box mirrors that of technological progress in the development of post-war growth economics.