Due to the absence of any signs of intelligence out there, especially paper-clippers burning the cosmic commons, we might conclude that unfriendly AI could not be the most dangerous existential risk that we should worry about.

I view this as one of the single best arguments against risks from paperclippers. I'm a little concerned that it hasn't been dealt with properly by SIAI folks - aside from a few comments by Carl Shulman on Katja's blog.

I suspect the answer may be something to do with anthropics - but I'm not really certain of exactly what it is.