Meaningfully engaging students in the NGSS scientific practices requires that student ideas become the driving force of classroom activity. However, in order for student ideas to take on this new role, teachers must engage in responsive teaching in which they elicit, notice, and respond to the substance of student thinking. In this work, we explore a variety of types of responsive teaching and elaborate a specific type of responsive teaching--what we call "epistemologically responsive science teaching." Using arguments drawn from existing literature on how to support the scientific practices, we present a theoretical argument that "epistemologically responsive science teaching" has the potential to scaffold student participation in the scientific practices. We present data from elementary-school pre-service teachers (PSTs) in science methods classes to demonstrate their abilities for engaging in this type of responsiveness and use this data to lend intuitive plausibility to our theoretical argument. This work has implications for how we support PSTs in learning about and enacting the scientific practices.