Also, one thing that struck me in Our Final Invention (which I reviewed here) was a quote in it from philosopher Nick Bostrom: "Our approach to existential risks cannot be one of trial-and-error. There is no opportunity to learn from errors. The reactive approach--see what happens, limit damages, and learn from experience--is unworkable." So I'll be reading the McArdle book with some thought as to what are the limits, as well as the power, of trial-and-error empiricism.
UPDATE 1/27: My review.