Does modern endogenous growth theory adequately represent Allyn Young?

Endogenous growth theory is now fashionable. It seeks to explainwhy per capita income growth in capital abundant countries isoften faster than in capital poor countries and defies the operationof diminishing returns. This theory, which took off with Romerand Lucas, often makes Allyn Young's concept of increasing returnsand Marshall's distinction between internal and external economiesits starting point but considers their treatment of the subjectas not sufficiently rigorous. The modern endogenous growth theoriststhen claim to explain what they had in mind with greater clarity,rigour and depth. This paper argues that this is not the caseas these theorists actually misrepresent Young in importantways.