This paper proposes a theory for the evolution of knowledge diffusion and growth over the very long run. A feedback mechanism between capital accumulation and knowledge spillovers creates a unified growth theory that explains a long epoch of (quasi-) stasis and an epoch of high growth linked by...

A core mechanism of unified growth theory is that accelerating technological progress induces mass education and, in interaction with child quantity-quality substitution, a decline in fertility. Using unique new data for 21 OECD countries over the period 1750-2000, we test, for the first time,...