A brilliant CHI paper by Steven Jackson and Sarah Barbrow. How many papers presented at CHI cite St. Augustine of Hippo and, to boot, succeed in drawing out relevant reflections on scientific modelling tools in ecology. Seeing ecology through the lens of both infrastructure and the ‘vocational calling’ provides a productive view onto what ecologists do and how their practices are changing. Jackson and Barbrow illustrate this nicely by writing of the changing notion of ‘the field’ for ecologists. I see a strong parallel here between ecology and biology. Biology is a field very much in transition and the changes have much to do with the material encounters in biological work — with for example the changing nature of biologists’ work at ‘the bench’ and with experimental apparatus. The turn to machines, computation and algorithms is not only reshaping the practices but also refiguring what biologists know and how they see their phenomena (something we also tried to get across in At the interface of biology and computation at CHI). A similar conclusion is being drawn out in this papers as it captures the entangled relations between the tools, practices and ways of knowing in ecology.