This paper offers a perspective on the relationship between communities that conduct research on teaching and learning in higher education, focusing on Higher Education Studies (HES) and science Discipline-Based Education Research (DBER). The paper responds to HES debates about the strength of its epistemological base and who belongs to that community, and to a perception that DBER is marginalized in the higher education research context. To explicate our perspective, we describe the origins and trajectories of Physics Education Research and Engineering Education Research, as exemplars of DBER. Using Turnbull, we conceptualize HES and these two exemplars as distinct "knowledge spaces," with different histories, orthopraxes and participants, and hence different unifying principles, research foci and trust mechanisms. We conclude that HES, DBER and other higher education research communities stand to benefit from multidisciplinary engagement with each other, because of their different perspectives on the problems of higher education.