The odds of computers becoming thoughtful enough to decide they want to take over the world, hatch a nefarious plan to do so, and then execute said plan remain exquisitely small. Yes, it’s in the realm of the possible. No, it’s not in the realm of the probable. If you want to worry about existential threats, I would suggest that the old-school Biblical ones — flood, famine, pestilence, plague, war — are still the best place to set your sights.
I would not argue with Carr about probable versus possible — he may well be right there. But later in the post, quoting from an interview he gave to help promote his book, he implicitly acknowledges that there are people who think that machine consciousness is a great idea and who are working to achieve it. He thinks that their models for how to do so are not very good and that their aspirations “for the near future” are ultimately based on “faith, not reason.”
Second, what he does not pause to notice is that everyone agrees that “flood, famine, pestilence, plague and war” are bad things. We spend quite a serious amount of time, effort, and money trying to prevent them or mitigate their effects. But at the same time, there are also people attempting to develop machine consciousness, and while they may not get the resources or support they think they deserve, the tech culture at least seems largely on their side (even if there are dissenters in theory). So when there are people saying that an existential threat is the feature and not the bug, isn’t that something to worry about?