Seemingly intuiting my desire for a quick diversion from politics into a more important topic, Kevin Drum links to this post by Stuart Staniford discussing the day, not long in coming, when Planet Earth's robots outnumber its humans, including a semi-serious projection that shows Them outnumbering Us some time in the early 2030s. Should we be worried? Well, yeah, but not because they're going to kill us all. The problem is capitalism.
Keep in mind that even as the number of robots increases dramatically, that doesn't mean there will be millions of self-aware humanoid machines walking around, planning the day when they finally rise up against their meat-sack oppressors. Instead, there will lots and lots of relatively simple robots doing things that now can only be done by humans, and nearly all of them will look nothing like us. Can a robot run a burrito truck? Not now it can't, but some steady advances in speech recognition and mechanical coordination will certainly bring that day before long. Amazon recently bought Kiva Systems,a company that makes robots that bring items to warehouse workers for packing, instead of the workers having to run all over the warehouse finding the items. That's fine for now, but it's pretty obvious that before too long, the robotic systems will become sophisticated enough that you won't need the workers at all (or at least you'll only need a few of them). In a few decades, the idea that we used to actually clean our own toilets and vacuum our own floors will seem ridiculous. Nevertheless, robots meant to look like people are probably going to remain little more than a curiosity for a long time, even as the more functional robots multiply.
It has been pointed out that the primary threat of globalization comes to the jobs in the middle of the work force, while many of the jobs at the top and bottom remain relatively (though not entirely) safe. You can outsource a call center or a factory, but you can't have a low-paid worker in Vietnam clean out hospital bedpans or do neurosurgery in Michigan. We could be heading for a similar situation with automation, where robots hollow out the middle, and if you're a highly educated knowledge worker you're OK, while everyone else has to take the increasingly crappy jobs that still require a human. Over time, the capabilities of robots could press outward toward both top and bottom, until eventually they actually are able to both do the neurosurgery and clean the bedpans.
And that may be the real crisis point. It's one thing when a robot turns out to be just as good at legal research as a lawyer; the lawyer it displaces may have a rough time, but she'll probably find some other kind of gainful employment. But once robots take the low-skill jobs, the people who now do them will have few other options for employment.
The laziest techno-utopian visions often assume that once robots are doing all the work, the rest of us will be able to devote ourselves to creative endeavors and generally pursue our happiness, free of the crushing demands of work. The problem is, that assumes we'd be living in some kind of post-capitalist society, like on Star Trek, where we never really learn what people on Earth do with their days, but it certainly doesn't seem to involve labor. But that's unlikely to be our future, so we're all still going to have to find ways to get people to pay us for doing stuff. Otherwise we won't have the money to purchase the fruits of all those robots' labors. As Staniford says, "Depending on how good the roboticists get how quickly, there's going to become a point where there really isn't enough in it for a sufficiently large fraction of humanity. I simply see no way this trend can continue without eventually rendering almost all of us irrelevant. People's basic survival instincts will not tolerate that. However, by that point, there may very well be no easy way back, and all hell will break loose." In other words, the problem won't be that the robots will kill us, but that the rise of robots will disintegrate our society, none of us will be able to make a living, and we'll kill each other. On the other hand, wouldn't it be nice if a robot cleaned your toilet for you?