Humans tend to underestimate the likelihood of outcomes that can come about through many different paths (Tversky and Kahneman 1974), and we believe an intelligence explosion is one such outcome.
This sentence feels awkward to me. I'd rather see it replaced by something like "We focus on convergent outcomes because they are typically underestimated relative to detailed scenarios (Tversky and Kahneman 1974)."
Anyhow, great article!
Anna Salamon and I have finished a draft of "Intelligence Explosion: Evidence and Import", under peer review for The Singularity Hypothesis: A Scientific and Philosophical Assessment (forthcoming from Springer).
Your comments are most welcome.
Edit: As of 3/31/2012, the link above now points to a preprint.