"Scientists have gotten way too fond of invoking their authority to claim that "science" dictates their preferred policy solutions and claiming that any disagreement constitutes an attack on science. But, even assuming that scientists agree on the facts, science can only tell us something about the state of the world. It cannot tell us what policy is the best to adopt. Scientists' preferences are not "science." You cannot go from an "is" (science) to an "ought" (policy). Social science, particularly economics, can tell you something about the likely tradeoffs (hence some of my frustrations at Aspen). But it can't tell you which tradeoffs to make," - Virginia Postrel, making sense as usual.