In today's increasingly "flat" world of globalization (Friedman 2005), the need for a scientifically literate citizenry has grown more urgent. Yet, by some measures, we have done a poor job at fostering "scientific habits of mind" in schools. Recent research on informal games-based learning indicates that such technologies and the communities they evoke may be one viable alternative--not as a substitute for teachers and classrooms, but as an alternative to textbooks and science labs. This paper presents empirical evidence about the potential of games for fostering scientific habits of mind. In particular, we examine the scientific habits of mind and dispositions that characterize online discussion forums of the massively multiplayer online game "World of Warcraft". Eighty-six percent of the forum discussions were posts engaged in "social knowledge construction" rather than social banter. Over half of the posts evidenced systems based reasoning, one in ten evidenced model-based reasoning, and 65% displayed an evaluative epistemology in which knowledge is treated as an open-ended process of evaluation and argument.