Since March 11 we have heard, seen, and read analyses from countless experts on what is going on at the crippled Fukushima Daiichi plant. That these accounts have often been contradictory is hardly surprising, given the volatile state of affairs, and the different perspectives from which experts view the situation. In a rapidly developing emergency, we expect to see assessments that diverge and evolve quickly. Our lives are chock full of ambiguities, and we live with most of them quite comfortably. Not with this one.