1. The law of comparative advantage has not been repealed. Machines take away some jobs and create others, while producing more output overall.
2. That said, some particular kinds of machines increase the relative return to skilled labor. If the new jobs require working with computers, and working with computers effectively is hard, reemploying lower-skilled workers at good wages may be difficult.
3. Smart software, factor price equalization, and better measurement of value have all boosted income inequality. Returns to working for low-skilled workers have fallen or stagnated in many regions (not North Dakota). Returns for many higher skilled workers have risen, but most of them were working and working hard already.
4. Lower returns to unskilled labor mean (on average) that low-skilled laborers will work less. This effect may interact with government benefits but sometimes people decide to work less or search less hard for a job for reasons unrelated to benefits. These decisions may produce feedback which weakens pro-work norms in the broader culture.
5. The employment to population ratio will be lower than it otherwise would have been, because of “robots” but not only robots. The natural rate of unemployment will be higher too.
6. Many of the new service sectors jobs will be better suited to women rather than the most unruly men. Physical strength will matter less, conscientiousness and teamwork will matter more, and much of the burden of these adjustments will fall on lesser educated men.
7. Facebook makes it easier to get sex and keep friends without having a job.
8. There is good evidence for each of these propositions, although it may be questioned how great is their combined import. In the meantime, yes robots may lower employment, although the catchphrase “robots are destroying jobs” is misleading rather than illuminating.