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

Conventional R&D-based growth theory argues that productivity growth is driven by population growth but the data suggest that the erstwhile positive correlation between population and productivity turned negative during the 20th century. In order to resolve this problem we integrate R&D-based...

We set up a simple overlapping generation model that allows us to distinguish between life expectancy and active life expectancy. We show that individuals optimally adjust to a longer active life by educating more and, if the labor supply elasticity is high enough, by supplying less labor. When...