Prior to the decline of the whaling industry in the 1960s, scientific uncertainty issues often were raised in the International Whaling Commission to argue against lower Antarctic quotas. But by the1970s, many of the same uncertainty issues were being reinterpreted by former whaling nations (and others) as good reasons for adopting a moratorium on all commercial whaling. This article argues that because science is unable to provide certainty, due to fundamental problems in its epistemology, the treatment of scientific advice by policy makers in the commission and elsewhere should be understood in relation to the utility it is believed to provide rather than simple claims of science's ability to provide truth or accuracy about the "real" world.