This article discusses a case for a different, socio-cultural way of looking at learning progressions as treated in the next generation science standards (NGSS) as described by Ralph Cordova and Phyllis Balcerzak's paper "Co-constructing cultural landscapes for disciplinary learning in and out of school: the next generation science standards and learning progressions in action". The paper is interesting for a number of reasons, and in this response I will identify different aspects of the paper and link the points made to my own research, and that of colleagues, as complementary perspectives. First, the way that the science curriculum is conceived as an expanding experience that moves from the classroom into the community, across subjects, and across time, links to theoretical positions on disciplinary literacies and notions of learning as apprenticeship into the discursive tools, or 'habits of mind' as the authors put it, that underpin disciplinary practice. Second, the formulation of progression through widening communities of practice is a strong feature of the paper, and shows how children take on the role of scientists through this expanding exposure. I will link this approach to some of our own work with school-community science partnerships, drawing on the construct of boundary crossing to tease out relations between school science and professional practice. Third, the demonstration of the expansion of the children's view of what scientists do is well documented in the paper, illustrated by Figure 13 for instance. However I will, in this response, try to draw out and respond to what the paper is saying about the nature of progression; what the progression consists of, over what temporal or spatial dimensions it progresses, and how it can productively frame curriculum processes.