Here's a poser that occurred to us over the summer, and one that we couldn't really come up with any satisfactory solution to. The people who work at the Singularity Institute have a high estimate of the probability that an Unfriendly AI will destroy the world. People who work for http://nuclearrisk.org/ have a very high estimate of the probability that a nuclear war will destroy the world (by their estimates, if you are American and under 40, then nuclear war is the single most likely way in which you might die next year).
It seems like there are good reasons to take these numbers seriously, because Eliezer is probably the world expert on AI risk, and Hellman is probably the world expert on nuclear risk. However, there's a problem - Eliezer is an expert on AI risk because he believes that AI risk is a bigger risk than nuclear war. Similarly, Hellman chose to study nuclear risks and not AI risk I because he had a higher than average estimate of the threat of nuclear war.
It seems like it might be a good idea to know what the probability of each of these risks is. Is there a sensible way for these people to correct for the fact that the people studying these risks are those that have high estimate of them in the first place?
Nuclear weapons have been available on the "black market" (thanks to sloppy soviet handling practices) for decades, yet no terrorist or criminal group has ever used a nuclear fission initiation device. Nuclearrisk.org claims "terrorists may soon get their own button on the vest", citing Al-Qaeda's open desire to acquire nuclear weapons.
I am unable, if I assume fully honest and rational assessments, to rectify these points of fact with one another. They disagree with each other. Given the fact that, furthermore, many of these assessments of risk seem to carry the implicit assumption that if a single nuke is used, the whole world will start glowing in the dark ( see: http://news.stanford.edu/news/2009/july22/hellman-nuclear-analysis-071709.html for an example of this (Martin Hellman himself) ) -- well, it gets further absurd.
In other words; folks need to be careful, when crafting expert opinions, to avoid Déformation professionnelle.