The world is awash in more debt than there is money enough in the world to liquidate it.

Reality is a wave function traveling both backward and forward in time.

I think that in the immediate aftermath of a superhuman machine intelligence revealing itself, most people would feel very threatened but take solace in the thought that we can always pull the plug.

System theorists know that it's easy to couple simple-to-understand systems into a "super system" that's capable of displaying behavioral modes that cannot be seen in any of its constituent parts. This is the process called "emergence."

My own guess is that quite quickly the machine intelligence will start dreaming machine dreams and thinking machine thoughts, both of which would totally incomprehensible to us. This would then lead to each species, we and the machines, moving off on to its own separate life trajectory.

If you ask which of the scenarios I think is most dangerous, though, I will give a different answer. In that form of the question, I regard a nuclear attack, terrorist-generated or otherwise, as the most threatening combination of likelihood and long-term damage to modern life today.

In fact, the very nature of an X-event is that it is both rare and surprising. So I would not say that any specific X-event is likely. What I would say, though, is that some X-event is not only plausible, but very likely in a time scale of a few years.