Is a singularity just around the corner ? What it takes to get explosive economic growth

Economic growth is determined by the supply and demand of investment capital; technology determines the demand for capital, while human nature determines the supply. The supply curve has two distinct parts, giving the world economy two distinct modes. In the familiar slow growth mode, rates of return are limited by human discount rates. In the fast growth mode, investment is limited by the world's wealth. Historical trends suggest that we may transition to the fast mode in roughly another century and a half. Can some new technology switch us to the fast mode more quickly than this? Perhaps, but such a technology must greatly raise the rate of return for the world's expected worst investment project. It must thus be very broadly applicable, improving almost all forms of capital and investment. Furthermore, investment externalities must remain within certain limits.