The problem is more general. The primary way to lower costs is to eliminate human workers. That is progressing rapidly as automation becomes more flexible and capable.

Already there have been successful robot waitresses, and as robot costs drop we'll see that last resort low-paid job begin to disappear too.

And truck drivers will probably be out within 20 years, as autonomous vehicles become widely available and accepted. Google has demonstrated them already, as have various university research groups. Nevada has licensed them. The military wants them. I want them--when I'm no longer able to drive safely, or when I'd rather read a book while going somewhere, I want an autonomous car.

So we face a much more serious problem as a society: there are not going to be nearly enough jobs. But we need consumers, everyone needs money. How will people get money, and health insurance, if there are no jobs for them?

Stop progress to preserve jobs? That's going to seem like make-work, not very satisfying.

Expand welfare?

The only writer I'm aware of who has seriously dealt with this issue is James Albus, a roboticist, who wrote "People's Capitalism". It's an unfortunate choice of title, kind of turns people off, but a good thoughtful book.

His basic idea is to acknowledge the common ownership of our system and infrastructure by giving everyone a literal share in it, like a grand mutual fund, when they turn 18. The shares generate dividends, and the fund promotes progress in technology, giving everyone a vested interest in making things better. He estimated that about 20 years after starting this system, the dividends would amount to enough to survive on and by combining two or more people one could live reasonably.

He also figures this income would enable marginal creative enterprises, like "hobby" leatherwork, so people could spend time doing things they enjoy but mostly supported by their investment in this fund.

The virtue is it's living like the rich do now, off investment income. There's no welfare stigma associated with that.

Seems to me we need to start thinking seriously about some such solution to the oncoming joblessness problem.

The ridges tilt when there are sideways components of force, resulting in pressure differences between the two sides of each ridge. The skin has only pressure force sensors, no tangential force sensors, so the ridges allow sensing tangential forces without needing some new kind of nerve/sensor system. That is important for gentle gripping, for example, so you can tell when a tighter grip is needed to prevent slipping. So the pressure sums or averages give the total normal force, and the local differences give the tangential components of the force. Useful.