Two quite detailed scenarios have emerged, one the Moravec/Kurzweil scenario, which we might call the 'Out to Pasture in the Elysian Fields,' that foresees machines as intelligent as humans, maybe more so, in 50 years and on the whole, a good thing. This leads to questions both Moravec and Kurzweil, to their credit, raise about whether those machines will take over for us (or from us), the basis of the second scenario, Bill Joy's quite opposite and dark vision, which posits the same improvement in machine intelligence, but with a horrifying outcome, the 'NanoGenRoboNightmare.' Some believers in the Elysian fields scenario have been arguing about 'the singularity,' borrowed from science fiction writer Vernor Vinge, the moment AI becomes powerful and ubiquitous enough so that all of the rules change and there's no going back. [...] I don't consider either of these scenarios implausible.