in science. This discussion of talk and argument leads naturally into consideration of the role of cultural habits and values in learning science. Science brings its own norms for both social and cognitive participation, which often differ quite markedly from children’s experiences in everyday settings. Finally, we consider how motivation and identity play a role in science learning and successful participation in science.
According to Bazerman (1988), the central activity of scientists is argumentation in communities of practice for the purpose of persuading colleagues of the validity of one’s own ideas and the ideas of others (see Latour, 1987). The focus of these arguments is on establishing agreement about the truth of symbolic objects. For example, Bazerman (1988) analyzed Newton’s journal articles over a period of years and concluded that experiments are communicated in a way meant to ensure that his interpretations would seem both logical and inevitable to readers. Newton employed a host of rhetorical devices, from the order of experiments reported (which often did not match their actual sequence) to the wording of sentences, all orchestrated to maximize the likelihood that readers would literally come to see things his way.
In spite of its centrality in science, genuine scientific argumentation is rarely observed in classrooms. Instead, most of the talk comes from teachers, and it seems oriented primarily toward persuading students of the validity of the scientific worldview (Ogborn et al., 1996). As Mehan (1979) described in his now-classic analysis of the structure of talk in school, the tacit turn-taking rules that guide the interaction of teachers and students seem guaranteed to preclude argument of any kind, and perhaps even genuine conversation. Mehan reported that the discourse structure he most frequently observed was one he called the initiate-response-evaluate triad. This familiar form of exchange begins with a teacher asking a question, usually one to which the answer is already known. A student is called on and responds, and the teacher then follows up with a comment that communicates an evaluation of the response. These sequences are intended to find out if the student can provide the answer expected by the teacher, not to communicate anything previously unknown, put forth a claim, justify or debate a point, or offer a novel interpretation.
Many teachers are uncomfortable with argument, perhaps understandably, given that many teach in contexts in which much of their time is spent mediating conflict and persuading students of the value of civil exchange. Skill and persistence are required to help students grasp the difference between scientific argument, which rests on plausibility and evidence and has