Will smart machines do to humans what the internal combustion engine did to horses – make them obsolete? If so, can putting people out of work or, at least, good work leave them unable to buy what smart machines produce? Our model's answer is yes. Over time and under the right conditions,...

Several recent theories emphasize the negative effects of an aging population on economic growth, either because of the lower labor force participation and productivity of older workers or because aging will create an excess of savings over desired investment, leading to secular stagnation. We...