So Joy isn't a scientist… so what, exactly, does that mean? Strikes me as not only an ad hominem attack, but a stupid one.

Joy, as an engineer used to working with complex, applied systems, is probably more qualified to project the long-term implications of really mature nanotech (and certainly more qualified to think about AI) than are the materials scientists who are doing the low-level work. He has more of a sense of what you can do with a technology after it "takes off".

It's, well, unscientific to say that scientists have any better chance of predicting how a mature system would act than anybody else, and especially than somebody who's actually worked with complex systems. This is even more true because these guys typically refuse to look at even the most obvious implications of what they're doing beyond the next one or two steps, or outside of their fields of specialty.

… and I say this as somebody who disagrees with practically everything Joy has said about this stuff.

The concept of quantum corrals is incredibly awesome, but are scientists sure that this is not simply an example of wave reflexion. I forget the actual term, but it's when you have say a rope tied to a fixed point, and when you shake your end so that there's a crest-trough thing traveling across the rope, after reaching the point the wave will just return but upside down. Anyway, maybe that's what happened, rather than a surprising and spontaneous reaction on the other side without any traveling done by the disruption in the middle.