Although we all have intuitive conceptions of students' "participation" and "engagement," understanding how little we know about these in practice is a crucial step toward better pedagogy. Students are often participating when we think they are not, and likewise, students can appear engaged, when in fact, they are not. In either case, teachers may find themselves encouraging what I call "studenting"-the performance of doing-being-a-student-rather than engaged participation. I argue that teachers and researchers must recognize (1) the complexity of (non-)participation and (dis)engagement, and (2) how much of students' participation and engagement is unknowable.