The ambition of this two-part article is to argue for immanent critique as a research strategy in sustainability studies. We do this by picking up and developing two central, cross-cutting themes in sustainability research, namely interdisciplinarity and normativity. It is widely suggested that the problem-driven and solution-focused orientation in sustainability studies necessitates interdisciplinarity and an engagement with questions of normativity, each creating problems regarding how science is conducted. For interdisciplinarity, questions remain regarding by what scientific procedure rational (i.e., non-arbitrary) interdisciplinarity can be accomplished. For normativity, it is unclear whether normativity can be addressed scientifically, or only politically; in other words, can normativity be objectively incorporated in sustainability research, and if so, how? Ultimately, the paper asks and answers the following questions: when should a researcher move from one discipline to another in sustainability research and, how do we judge the validity of the normative values that are deemed necessary for sustainability? In Part I, we show the silences, gaps, vagueness and inadequacies of how these themes are currently addressed in sustainability science literature, and from this move to propose immanent critique as a potential strategy for dealing with them in a scientific manner. In Part II, we exemplify our strategy by applying it to re-construct the debate over sustainable development, by far the most prominent topical focus in sustainability science research, producing a novel systematized typology of sustainable development approaches in the process. We conclude with reflections on how this paper amounts to an initial contribution to the construction of a Lakatosian research programme in sustainability studies.